April 2012

April 2012 [6(4) 2012]

Table of Contents

Southern Cross Publishing Group©2012

Protective role of glycinebetaine in maize against drought-induced lipid peroxidation by enhancing capacity of antioxidative system

Shakeel Ahmad Anjum, Muhammad Farrukh Saleem, Long-chang Wang, Muhammad Faisal Bilal, Asif Saeed

College of Agronomy and Biotechnology, Southwest University, Engineering Research Center of South Upland Agriculture, Ministry of Education, P. R. China
Department of Agronomy, University of Agriculture, Faisalabad, Pakistan
Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad, Pakistan

A pot-culture study was performed to investigate the efficacy of glycinebetaine (GB) for drought tolerance in two contrasting maize cultivars. Progressive drought stress noticeably reduced the relative  leaf water content (RLWC) but increased protein and proline concentrations in both cultivars. The reduction in RLWC in DD-60 was lower than ND-95, whereas, the accumulation of protein and proline  was substantially higher in DD-60 over ND-95 during experimental period. Nonetheless, GB-treatment led to increase in RLWC, protein and proline accumulation in DD-60 than ND-95. Prolonged  drought stress induced the membrane lipid peroxidation, which was more severe in ND-95 than DD-60. GB-treatment substantially ameliorated the lipid peroxidation in DD-60 over ND-95 under drought  stress. The activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were substantially enhanced in DD-60 than ND-95 with the prolongation of drought stress at beginning and  then declined subsequently. These results possibly suggest that the DD-60 showed a better protection mechanism against water-induced lipid peroxidation by maintaining higher constitutive activities of  antioxidant enzymes than ND-95. Nevertheless, GB-treated plants maintained higher antioxidant enzymes activity during drought stress than non-GB treated plants, which ultimately enhanced the  growth, yield and yield components. The foliar application of glycinebetaine only considered advantageous when applied under drought and exhibit pronounced effects when applied at flowering.  Drought tolerance can be improved in maize by the foliar GB-treatment through enhancing the antioxidants capacity.

Pages 576-583 | Full Text PDF
Influence of drying methods on activation energy, effective moisture diffusion and drying rate of pomegranate arils (Punica Granatum)

Saeid Minaei, Ali Motevali, Gholamhassan Najafi, Seyed Reza Mousavi Seyedi

Department of Agricultural Machinery Engineering, Tarbiat Modares University, Tehran, Iran  
Department of Mechanic of Agricultural Machinery, Sari Agricultural Science and Natural Resources University, Sari, Iran

In this investigation, thin layer drying behavior of sour pomegranate arils using microwave, vacuum, and infrared methods as well as convection drying (three treatments including control and microwave pretreatments at 100 and 200 W) was studied. Effect of these drying methods on drying rate, effective moisture diffusion and activation energy was analyzed. It was observed that microwave pretreatment increases drying rate and effective moisture diffusion while it decreases activation energy. The highest values of drying rate and effective moisture diffusion were 0.965 g/min and 7.709×10-10 m2/s obtained with pretreatment power of 200 W at air temperature and velocity of 70 °C and 1.5 m/s. while the lowest values were 0.082 g/min and 0.856×10-10 m2/s for the control samples at 45 °C temperature and 0.5 m/s air velocity. Effective diffusion coefficient of pomegranate arils was in the range of 6.77×10-10 to 52.5×10-10 m2/s, 3.43×10-10 to 29.19×10-10 and 4×10-10 to 32×10-10 m2/s for vacuum, microwave and IR dryers, respectively. Activation energy for pomegranates in the vacuum dryer was 52.83 kJ, while in the microwave dryer it was 23.563(W/g). Activation energy in the microwave dryer was calculated using the Arrhenius exponential model. A comprehensive comparison of the various dryers revealed that microwave pretreatment combined with convective drying performed best for the drying of pomegranate arils taking into consideration the drying rate, effective moisture diffusion and activation energy.

Pages 584-591 | Full Text PDF
Investigating energy consumption and quality of rough rice drying process using a grain heat pump dryer

Mehdi Torki Harchegani, Morteza Sadeghi, Mohsen Davazdah Emami and Ahmad Moheb

Department of Farm Machinery, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran
Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, Iran
Department of Chemical Engineering, Isfahan University of Technology, Isfahan, Iran

In this study, energy consumption and quality of rough rice drying process were investigated using a laboratory designed and fabricated grain heat pump dryer. Designing of the heat pump dryer was carried out based on a newly developed non-equilibrium model for the numerical simulation of rough rice drying in a deep-bed mode. For this purpose, the partial differential equations of rough rice drying were solved in MATLAB software. After solving the governing drying equations and heat pump simulation in HYSYS software, a 184 W compressor, an evaporator, an expansion valve and two condensers, were used to fabricate the heat pump system. Rough rice was selected as the material for evaluation of the setup. The rough rice fissuring difference before and after drying decreased about 40% in heat pump dryer mode in comparison with conventional dryer (6 vs. 10%). Moreover, despite of consuming power by compressor in heat pump dryer mode, the total power consumption reduced about 10% compared to the hot air dryer alone. Therefore, it is concluded that the fully closed loop heat pump dryer system could be applied for rough rice drying.

Pages 592-597 | Full Text PDF
Effect of water regimes on germination of weed seeds in a Malaysian rice field

Abdul Shukor Juraimi, M.S. Ahmad-Hamdani, A.R. Anuar, M. Azmi, M.P. Anwar, and M. Kamal Uddin

Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
Pusat Penyelidikan Tanaman Makanan & Industri, MARDI Seberang Perai, Peti Surat 203, 13200 Kepala Batas, Pulau Pinang, Malaysia
Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

The effect of different water regime treatments on the viability of weed seeds in direct-seeded rice field was evaluated. Five water regime treatments were used namely, continuous flooding condition until maturity, early flooding until 55 DAS (day after sowing) followed by saturated condition until maturity, early flooding until 30 DAS followed by saturated condition until maturity, continuous saturated condition until maturity, and continuous field capacity condition throughout the experimental period. Total weed seed population in soil sampled from March-May. The results showed that weed population dominated by broadleaved weeds (90625 seeds m-2), mainly Hedyotis corymbosa, Monochoria vaginalis and Ludwigia hyssopifolia, followed by sedges (34257 seeds m-2), mostly F. miliacea and Cyperus iria. The grasses, predominantly Leptochloa chinensis, recorded the lowest number in all water regime treatments (20647 seeds m-2). In soils sampled from September-November, sedges (53041 seeds m-2) mainly Fimbristylis miliacea along with broadleaved weeds (54624 seeds m-2), predominantly Monochoria vaginalis and Ceratopteris pteridoides, dominated in most of the water regime treatments, while grasses, mainly Leptochloa chinensis and Panicum repens, recorded the lowest number (24935 seeds m-2). Ten weed species, which were not observed in the field trials, were recorded from the same soils used in the weed seedbank study. The results showed that differences in water regime treatments did not significantly reduce the viability of weed seeds in the soil. However, a small reduction in seed viability (approximately 8%) was observed in soil samples during the September-November period.

Pages 598-605 | Full Text PDF
Marker validation in recombinant inbred lines and random varieties of rice for drought tolerance

Sanjay Singh, S.K.Pradhan, A.K.Singh and O.N.Singh

Sanjay Singh, Senior Scientist, Division of Genetics, Indian Agricultural Research Institute, Pusa, New Delhi-110012, India
Sharat Kumar Pradhan, Senior Scientist, Central Rice Research Institute, Cuttack, Orissa, India
Onkar Nath Singh, Head, Crop Improvement Division, Central Rice Research Institute, Cuttack, Orissa, India
Ashok Kumar Singh, N.D. University of Agricultural & Technology, Kumarganj, Faizabad, Uttar Pradesh, India

Water stress, one of the devastating abiotic stresses in rainfed rice ecosystems causes huge loss to rice yields. Enhancement of production as well as productivity in rainfed areas requires development of improved varieties for such regions. Slow progress in drought breeding is an impediment in this way. Marker assisted approach is an alternative for fast track improvement of crops for drought. Validation of QTLs associated with drought related traits across the populations would add value to their application. In the present study, two SSR markers RM60 and RM252 reported earlier for root thickness were evaluated for their association with a set of DH lines derived from the cross of CT9993 × IR68766 and recombinant inbred lines (RILs) derived from cross of IR66366 × IR66876 as well as on a set of twenty cultivars / landraces of rice adapted to the rain fed lowland and upland ecosystems. The marker RM252 was consistently associated with the root thickness in all these cultivars and populations, and is therefore suitable for adoption in marker assisted selection for the root thickness and penetrating ability. The other marker, RM60 distinguished the thick-rooted and thin-rooted parents, CT9993 and IR68566, showing higher and lower molecular weight alleles, respectively, but it did not show one to one association with the thick and thin rooted phenotypes among the RILs. Besides, RM60 could not be validated in the RILs of IR66366 and IR66876 because it did not show polymorphism. The association of RM252 was much stronger than that of RM60. Marker assisted improvement through this approach can be applied for QTL transfer in multiple genetic backgrounds.

Pages 606-612 | Full Text PDF | Supplementary data
Absorption and accumulation characteristics of nitrogen in different wheat cultivars under irrigated and dryland conditions

SUN Min, GAO Zhi-Qiang, YANG Zhen-Ping, HE Li-Heng

College of Crop Science, Shanxi Agricultural University, Taigu, 030801, China

To investigate the N absorption and accumulation characteristics of different wheat cultivars, twelve wheat cultivars with different drought tolerance were planted under both irrigated and dryland conditions. Compared with the irrigated condition, wheat N accumulation was significantly decreased at each growth stage under dryland cultivation, with the maximum decline in weak drought-resistant cultivars (more sensitive) (SN129, SN9-1, 40081, and CZ9578), secondly the moderately-tolerant (40345, 40035, SN121, and ZM175) and then strong drought-resistant cultivars (040521-135, JM47, 9801-C, and ND189). Furthermore, dryland condition decreased the N absorption ratio at anthesis-maturity stage, post-anthesis N accumulation and its contribution to grain N content. On the contrary, the N absorption ratio at jointing-anthesis stage and the contribution of pre-anthesis N translocation to grain N content were increased. Therefore, under dryland condition, we suggest that strong drought-resistant wheat cultivars should be popularly cultivated. These cultivars could significantly improve pre-anthesis N absorption and the translocation from pre-anthesis vegetative organs to post-anthesis grain, resulting in higher N use efficiency and high wheat yield.

Pages Pages 613-617 | Full Text PDF | Supplementary data
Early assessment of genetic fidelity in sugarcane (Saccharum officinarum) plantlets regenerated through direct organogenesis with RAPD and SSR markers

R.N. Pandey, S.P. Singh, J. Rastogi, M.L. Sharma and R.K. Singh

Sugarcane Research Institute, UP Council of Sugarcane Research, Shahjahanpur, U.P. India

Early assessment of genetic fidelity of micropropagated plants aids in fine tuning protocol parameters and gauge suitability of regeneration protocol for large scale applications. Induction of direct organogenesis leading to reduced duration in vitro can lead to production of genetically stable plantlets. The present work describes early assessment of clonal fidelity in Sugarcane plants regenerated through direct organogenesis using RAPD and SSR markers. Analysis of RAPD banding patterns generated by PCR amplification using 20 random primers gave no evidences for somaclonal variation and the percent of polymorphic bands in a total of 110 amplicons was 0.02%. RAPD patterns of the plantlets were identical with the original mother plant, indicating that direct adventitious organogenesis did not induce somaclonal variation that can be detected by RAPD.  Mean while SSR banding pattern analysis generated with 15 primers (112 amplicons) also gave no evidences for somaclonal variation. The genetic fidelity testing of micro-shoots, based on a RAPD and SSR analysis indicated a strong genetic purity like the parent genotype. Lack of variation confirms the genetic purity of tissue culture plants of sugarcane raised through direct organogenesis in young whorl leaf roll explants and confirms to the suitability of overall regeneration protocol.

Pages 618-624 | Full Text PDF
Classification of genetic variation in garlic (Allium sativum L.) using SSR markers

Man Hyun Jo, In Ki Ham, Kyaw Thu Moe, Soon-Wook Kwon, Fu-Hao Lu, Yong-Jin Park, Woon Seob Kim, Mi Kyoung Won, Tae Il Kim, Eun Mo Lee

Chungcheongnam-do Agricultural Research & Extension Services, Yesan 340-861, Republic of Korea
Department of Plant Resources, College of Industrial Science, Kongju National University, Yesan, 340-702, Republic of Korea
Legume Bio-Resource Center of Green Manure (LBRCGM), Kongju National University, Yesan 340-702, Republic of Korea

Garlic bulb is an important seasoning ingredient in many of the world's cuisines. However, clonal lineages within this species show a remarkably high degree of phenotypic diversity in bulb size and color. Present study classified the genetic variations of garlic. Seven selected simple sequence repeats (SSRs) revealed a total of 37 alleles across 120 garlic accessions, with an average of seven alleles per locus. The values for observed heterozygosity ranged from 0 to 0.99 (mean = 0.71). The average genetic diversity and polymorphic information content values were 0.586 and 0.518, respectively. Based on the 37 alleles obtained from the seven SSRs, a phylogram was constructed to understand the relationships among the 120 accessions. The garlic accessions were clustered into four main groups (G1-G4) in the phylogram. Group 1 consisted of accessions of ‘Aomori’, Group 2 consisted of 64 accessions, Group 3 consisted of 25 accessions, and Group 4 consisted of 20 accessions. Our results indicate that genetic diversity is correlated with geographical region. There may have been local selection pressure and differences in adaptability of the garlic to different geographical conditions. All of the tested loci deviated significantly (P < 0.01) from Hardy-Weinberg equilibrium. Thus, a number of disturbances occurred in the garlic population tested, including natural selection. Our findings will help explain the genetic relationships and population structure of garlic accessions.

Pages 625-631 | Full Text PDF | Supplementary data
Differential response to elevated NaCl by antioxidant enzymes and gene transcripts in two contrasting lettuce genotypes

Hela Mahmoudi, Mouhiba Ben Nasri, Olfa Baâtour, Jun Huang, Imen Tarchoun, Nawel Nasri, Kaddour Rym, Margaret Gruber, Mokhtar Lachaâl, Abdelali Hannoufa and Zeineb Ouerghi

Physiologie et Biochimie de la Tolérance au Sel des Plantes, Faculté des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar, Tunisia
Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, SK, Canada S7N 0X2
Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, Canada N5V 4T3

Enzyme activities and transcript profiles of major antioxidant enzymes in two contrasting cultivars of lettuce seedlings (Lactuca sativa L.) were profiled after a 15 day period growing in 100 mM and 200 mM NaCl. Total superoxide dismutase activity (SOD) was enhanced in the more saline-tolerant‘Verte de Cobham’ cultivar in response to NaCl, and this was accompanied by increased expression of Fe-SOD and Mn-SOD genes at the two salt concentrations. Transcripts for these two genes were limited in the more salt sensitive ‘Romaine’ cultivar, while CuZn-SOD transcription remained consistent across all salinity levels in both cultivars. Ascorbate peroxidase (APX) enzyme activity was more than 1000-fold lower than total SOD activity in both cultivars in roots and leaves, even though APX enzyme activity increased with salinity in ‘Verte’ leaves. Catalase (CAT) and gaiacol peroxidase (GPX) enzyme activity were ~100-fold lower than total SOD enzyme activity in both leaves and roots, but did not appear to be limiting in salt-sensitive ‘Romaine’ at the lower NaCl concentration. The pattern of root activity for these two latter enzymes differed between the two cultivars, and CAT transcripts disappeared in ‘Romaine’ roots at the higher salt concentration. Our findings suggest that lettuce could benefit from enhancement of antioxidant enzymes through molecular or traditional plant breeding, although clearly such an effort would be of greater benefit to ‘Romaine’.

Pages 632-640 | Full Text PDF
Tolerance for cadmium pollution in a core-collection of the model legume, Medicago truncatula L. at seedling stage

Ghodratollah Saeidi, Martina Rickauer, Laurent Gentzbittel

Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan  University of Technology, Isfahan 84156-83111, Iran
Université de Toulouse, INP, UPS, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), ENSAT, 18 chemin de Borderouge, 31326 Castanet Tolosan, France
CNRS, EcoLab, 31326 Castanet Tolosan, France

Development of cadmium (Cd) tolerant cultivars in legumes is important for crop production in contaminated soils. This research was carried out to quantify Cd-tolerance of 27 accessions from a core-collection of the model legume, Medicago truncatula. Root growth, relative root growth (Cd-treated /untreated seedlings) and tolerance index (difference of root growth between Cd-treated and untreated seedlings) were considered as the indices of tolerance to this toxic metal. Cadmium significantly and considerably decreased root growth, root fresh weight, root and shoot dry weight, but increased shoot water content and root diameter. Root growth was most affected by Cd and decreased to 59, 57 and 60% of control treatment after 2, 4 and 6 days, respectively. The accessions significantly differed for seedling root growth in Cd-stress condition, tolerance index and relative root growth. These indices varied from 4.33 to 12.51 mm, 3.58 to 18.92 mm and 0.25 to 0.64 with broad-sense heritabilities of 61, 73 and 57%, respectively. Based upon the results of root growth in Cd-stress condition, accessions L144  (originated from Jordan) and L648 (originated from France) were recognized as the most tolerant and susceptible genotypes, respectively. In conclusion, the results indicated the existence of genetic variation for Cd- tolerance at seedling stage and root growth can be rapidly and simply used as a good index of tolerance in breeding programs.

Pages 641-648 | Full Text PDF
Molecular cloning and expression of 12-oxophytodienoic acid reductase gene from barley

Saeid Abu-Romman

Department of Biotechnology, Faculty of Agricultural Technology, Al-Balqa’ Applied University, Al-Salt, 19117, Jordan

The 12-oxophytodienoic acid reductases (OPRs) are flavin mononucleotide-dependent oxidoreductases that catalyse the reduction of double bonds in
a,ß-unsaturated aldehyde and ketones and some of them are part of the octadecanoid pathway leading to jasmonic acid biosynthesis. In this paper, a member of the OPR gene family (HvOPR1) was isolated from barley, the full length cDNA of HvOPR1 was 1298 bp containing a 1089 bp ORF encoding 362 amino acids. Bioinformatic analyses revealed that the deduced HvOPR1 has considerable homology with other plant OPRs. Phylogenetic analysis showed that HvOPR1 codes for OPR of subgroup I, containing enzymes which are not required for jasmonic acid biosynthesis. Expression of HvOPR1 during development and in response to abiotic stresses and hormonal treatments was analyzed by semi-quantitative reverse-transcription PCR. HvOPR1 expression was differentially regulated during primary leaf development and up-regulated in response to drought, hydrogen peroxide and wounding. Moreover, the accumulation of HvOPR1 mRNA was increased in response to jasmonic acid, salicylic acid and abscisic acid. The results suggested that HvOPR1 might play an important role during development and in response to abiotic stresses and signaling molecules.

Pages 649-655 | Full Text PDF
Molecular and farmer-based comparison of a wild-weed and landrace complex of watermelon in Zimbabwe

Claid Mujaju, Gun Werlemark, Larisa Garkava-Gustavsson, Marinus J. M. Smulders, Hilde Nybom

Department of Plant Breeding and Biotechnology - Balsgård, Swedish University of Agricultural Sciences, Fjälkestadsvägen 459, 291 94 Kristianstad, Sweden
Wageningen UR Plant Breeding, P.O. Box 16, NL-6700 AA Wageningen, The Netherlands
Seed Services, Department of Research and Specialist Services, Ministry of Agriculture, Mechanization and Irrigation Development, Box CY550, Harare, Zimbabwe

Traditional farming systems have been associated with the occurrence of intervarietal and interspecific natural crosses in many crop plants, thus contributing to the genetic diversity of the crop through genetic exchange. In this study, a combination of farmer-preferred morphological traits and RAPD markers were used to evaluate the dynamics of genetic diversity in 43 watermelon accessions collected at a single village level with a traditional farming system. The molecular variability assessed with RAPD markers and analyzed with multidimensional scaling and cluster analysis, demonstrated a substantial differentiation among the accessions. Population structure analysis also demonstrated the existence of three major forms of watermelon, identified by a set of alleles predominant within each form. Dendrograms based on RAPD data and on farmer-preferred traits data were positively correlated according to a Mantel test. Although cultivated cow-melons were genetically most similar to wild-weedy plants at molecular level, they grouped more similar to sweet watermelons based on farmer-preferred traits. The present study revealed limited gene flow between three forms of watermelon and provides insight into how the genetic differentiation corresponds to farmers’ classification of watermelons.

Pages 656-661 | Full Text PDF
The effects of irrigation and nitrogen application rates on yield of spring wheat (longfu-920), and water use efficiency and nitrate nitrogen accumulation in soil

Qi Wang, Fengrui Li, Enhe Zhang, Guan Li, Maureen Vance

College of Grassland Science, Gansu Agricultural University, Lanzhou, Gansu Province 730070, China
Cryosphere Research Station on the Qinghai-Tibet Plateau and State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu Province 73000, China
Linze Inland River Basin Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu Province 73000, China
Agronomy College, Gansu Agricultural University, Lanzhou, Gansu Province 730070, China
College of Information Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
The Adult Reading Assistance Scheme, Christchurch, New Zealand

In the middle reaches of Heihe River Basin, the environmental deterioration caused by excessive nitrogen (N) and irrigation application in agricultural ecosystems has received much attention in recent years. A combination of careful irrigation and N management is needed to improve N uptake efficiency and to minimize potential nitrate (NO3--N) leaching. A field experiment was designed to investigate the effects of different irrigation and N application rates on grain yield, water use efficiency (WUE) and soil nitrate-N (NO3--N) accumulation on a recently reclaimed sandy farmland at the margin of the Gobi Desert in 2006 and 2007. The experiment followed a completely randomized split-plot design, taking the various irrigation treatments (0.6, 0.8 and 1.0 of the estimated evapotranspiration-ET) in the main-plots and N supply treatments as split-plot (with five levels of 0, 79, 140, 221 and 300 kg N ha-1). The results indicated a wide annual variability in grain yield, kernel numbers and straw yield, mainly due to greater rainfall and irrigation rates in the second year. A significant irrigation effect was observed on grain yield, kernel numbers and straw yield. The highest levels were achieved with a high irrigation supply, although WUE generally decreased linearly with increasing seasonal irrigation rates in 2 years. The low irrigation treatment (0.6 ET) produced significantly lower grain yield (20.7 %), kernels number (9.3 %) and straw yield (12.2 %) than high irrigation treatment (1.0 ET). The low irrigation treatment had a higher WUE (4.25 kg ha-1 mm-1) than that of 3.25 kg ha-1 mm-1 with high irrigation over the 2 years. On contrary to the irrigation, the N application rate of 221 kg ha-1 had the highest values of grain yield, kernel numbers, straw yield and WUE under the 3 irrigation regimes. The average grain yield of 221 kg N ha-1 were found to be 99.1, 45.1, 20.0 and 7.4 % higher than those of 0, 79, 140 and 300 kg N ha-1, respectively over the 2 years. The 221 kg N ha-1 had the highest WUE (4.75 kg ha-1 mm-) among all N treatments. No more NO3--N accumulation was found in the 200 cm soil profiles under the medium (0.8 ET) and low irrigation, when the N application was below 221 kg ha-1, at harvesting stage and there was a little potential for NO3--N leaching. High irrigation led to a high NO3--N leaching and a high plant N-uptake, resulting in lower NO3--N accumulation at the harvest stage compare to the sowing or soil preparation stage. This was within the 200 cm soil profiles and over the 2 wheat growing seasons. The N application rate of 221 kg N ha-1 produced a high grain yield of spring wheat, but the N application rate was lower than that of 221 kg N ha-1 as concerned NO3--N accumulation at harvesting stage under deficit irrigation. The optimum economic N rates ranged from 174 to 226 kg ha-1.

Pages 662-672 | Full Text PDF
Development of Sea Island cotton (Gossypium barbadense L.) core collection using genotypic values

Yongjun Mei, Jiaping Zhou, Haiming Xu and Shuijin Zhu

College of Plant Science and Technology, Tarim University, Alar, Xinjiang 843300, PR China
Institute of Bioinformatics, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China
Department of Agronomy, College of agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, PR China

A core collection usually provides an effective entry to access to entire genetic resource. It could simplify screening potential of breeding materials in a manageable size. In order to phenotypic evaluations, a completely randomized block designed experiment was carried out in 265 Sea Island cotton varieties. A mixed linear model approach was employed to predict genotypic values of two fiber quality traits and eight agronomic traits. Based on the genotypic values, some candidate core subsets were constructed using five hierarchical clustering methods combined with preferred and deviation sampling at three sampling proportions. The genetic variations captured by the subsets were compared in means, variances, ranges and coefficients of variation. The result revealed that core subset of 27 accessions, based on UPGMA clustering method combined with the deviation sampling strategy at 10% proportion (C4S2-10), exhibited maximum VR%, VD% and invariant MD% and CR%. Therefore, this subset was determined as the core collection of the Sea Island cotton. The representative and validation of the core collection was further examined by the accession distribution pattern plotted by the first two principal components, as well as the correlation coefficients. The core accessions with high fiber quality of lint cotton and yield of pre-frost cotton, being as important potential materials for quality or yield improvement, are worthy to be further studied.

Pages 673-680 | Full Text PDF
Phenolic content and antioxidant capacity of fruits of plum cv ‘Stanley’ (Prunus domestica L.) as influenced by maturity stage and on-tree ripening

Nemanja Miletic, Branko Popovic, Olga Mitrovic, Miodrag Kandic

Department for Fruit Processing Technology, Fruit Research Institute, Kralja Petra I/9, 32000 Cacak, Serbia

Fruits of plum ‘Stanley’ were analysed for total anthocyanins, total phenolics and antioxidant capacity over three successive harvest years. Fresh fruits were harvested five times per year. The total anthocyanins content ranged from 5 to 57 mg/100 g, expressed as cyanidin-3-glucoside equivalents, on a fresh-weight basis. The anthocyanin concentrations were higher in fruits of successive harvesting dates, meaning that anthocyanin accumulation seemed to occur constantly during fruit development and ripening. The total phenolic content was within the range of 70 to 214 mg gallic acid equivalents/100 g fresh weight. The highest concentrations of anthocyanins and phenolics were observed in plum fruits harvested in 2009, which is most likely due to the favourable weather conditions. The free radical galvinoxyl was used to evaluate antioxidant capacity of plum fruits. The total antioxidant capacity of fresh fruits, expressed as the rate constant k1’, ranged from 0.950 to 3.010 s-1. Antioxidant capacity also strongly depended on ripening stage, showing completely opposite trend compared to that of total phenolics. Since total phenolics and antioxidant capacity performed nearly ‘object and its reflection in the mirror’ trend, consequently the lowest antioxidant capacity was observed in plum fruits harvested in 2009.

Pages 681-687 | Full Text PDF
Biphasic effect of copper on growth, proline, lipid peroxidation and antioxidant enzyme activities of wheat (Triticum aestivum cv. Hasaawi) at early growing stage

Mohamed M. Azooz, Mona F. Abou-Elhamd, Mohamed A. Al-Fredan

Biological Sciences Department, Faculty of Science, King Faisal University, Saudi Arabia
Botany Department, Faculty of Science, South Valley University, 83523 Qena, Egypt

The biphasic effects of Cu+2 on the growth and some biochemical parameters of Hassawi wheat were studied. Hassawi wheat seeds were grown in various copper (Cu+2) levels (0, 2, 10, 20, 40, 80 and 100 mM) for 30 days. Cu+2 was applied on soil as Cu2SO4.5H2O. The results showed that Cu+2 concentration at 2 mM level promotes the growth and tested biochemical parameters of Hassawi wheat plants and can be considered as optimal dose. However, the studied parameters did not significantly change when Cu+2 applied more than the above mentioned concentration up to 10 mM, and thereafter the growth and biochemical parameters were significantly reduced, compared to untreated control plants. Furthermore, the activity of antioxidant enzymes such as, catalase, peroxidase, ascorbate peroxidase and superoxide dismutase were also increased. The results support the biphasic effect of copper on Hassawi wheat growth. The stimulatory effect of Cu+2 on the biosynthesis of free amino acids, proline and antioxidant enzyme activities could serve as important components of antioxidative defense mechanism against Cu2+ toxicity.

Pages 688-694 | Full Text PDF
Evaluation of biocontrol potential of Pseudomonas and Bacillus spp. against Fusarium wilt of chickpea

K. Karimi, J. Amini, B. Harighi, B. Bahramnejad

Department of Plant Protection, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran
Department of Agronomy, Faculty of Agriculture, University of Kurdistan, Iran

In this study, antagonistic effects of 6 isolates of Pseudomonas and 6 isolates of Bacillus genera isolated from rhizosphere of chickpea were evaluated against Fusarium oxysporum f. sp. ciceris as potential biocontrol agents in vitro and in vivo. Fungal inhibition tests were performed using plate assay. Each isolate were tested for the production of protease, siderophore, cyanide hydrogen, indole acetic acid, antifungal volatile and extracellular compound. Twelve isolates were selected according to their high antagonistic efficiency in in vitro which was shown as inhibition zones in the dual-culture assay. According to phenotypic properties, selected isolates were identified as Bacillus subtilis (B1, B6, B28, B40, B99, and B108), Pseudomonas putida (P9 and P10) and P. aeuroginosa (P11, P12, P66 and P112). The ability of bacterial isolates was varied in production of cyanide hydrogen, siderophore, protease and indole acetic acid (IAA). Biocontrol activity and plant growth promotion of bacterial strains were evaluated under greenhouse conditions, in which P. aeuroginosa (P10 and P12), B. subtilis (B1, B6, B28 and B99) and P. aeuroginosa (P12 and B28) provided better control (P = 0.05)  than untreated control (15.8…44.8%) in seed treatment and soil-inoculation, respectively. The growth parameters (plant height, fresh and dry weight of plants) were significantly increased by B28, P12 and P112 isolates in both tests compared to the untreated control. Our results indicate that PGPR improve growth parameters in this plant and can help in the biocontrol of pathogen.
Pages 695-703 | Full Text PDF
Effects of ear shading on the anthocyanin contents and quality of kernels in various genotypes of maize

Lina Cui, Rongqi Gao, Shuting Dong, Jiwang Zhang, Peng Liu, Haiyan Zhang, Jiajia Meng, Deyang Shi

State Key Laboratory of Crop Biology / Agronomy College of Shandong Agricultural University, Tai’an 271018, Shandong, P.R. China
Dezhou Agriculture Bureau, Dezhou 253000, Shandong, P.R. China

This study aimed to investigate anthocyanin accumulation and the effects of shading on the quality and anthocyanin contents of kernels in various genotypes of maize (Zea mays L.). The ears of four differently-colored cultivars of maize,  (Xixingheinuo NO. 1 [black], Zinuoxiang [purple], Xixingchinuo NO. 1 [red] and Yuxiangnuo [white]) were shaded after anthesis using opaque bags. Changes in grain colors of maize seeds during development under shading treatment and the location of coloration were observed. Anthocyanin, total phenolic compounds, starch, soluble protein and sugar contents, as well as phenylalanine ammonialyase (PAL) activity, were also measured. Over 99% of the anthocyanin content determined in Xixingchinuo NO. 1 was found in its pericarp and seed coat; in Zinuoxiang and Xixingheinuo NO. 1, over 99% of their anthocyanin contents were found in the aleurone layer. Shade treatment (The ears shaded after anthesis using opaque bags from anthesis until harvest) decreased the intensity of the kernels’ apparent color. Shade treatment significantly reduced anthocyanin production during the early grain filling stage of growth, but the difference in percentage of reduction between the control and shade-treated plants decreased during development. In contrast, differences of total phenolic contents between the control and shade-treated plants were increased, except Yuxiangnuo, Shade treatment decreased anthocyanin and total phenolic contents by 68.6%, 68.8%, 60.0% 56.1% and 20.6%, 3.6%, 6.6%, 10.0%, respectively, in Yuxiangnuo, Xixingchinuo NO. 1, Zinuoxiang, and Xixingheinuo NO. 1 15 d post-anthesis (DPA). Further decreases to 9.7%, 15.8%, 31.7%, 37.0% and 8.3%, 12.6%, 13.7%, 20.4%, respectively, were observed in the same plants at 50 DPA. These findings show significant differences in anthocyanin and total phenolic syntheses in maize. Shade treatment decreased PAL activity, soluble sugar and starch contents but increased soluble protein contents compared with control kernels. The results of this study indicate that fresh ears could be picked at about 35 DPA, at which point anthocyanin contents would be at maximum levels. Dissimilar farina pollination, as well as ensuring that plants receive good lighting, ears are not shaded, and the grain filling is good, could improve anthocyanin contents in maize

Pages 704-710 | Full Text PDF
Effects of calcium on eliminating the negative effects of salinity in pistachio (Pistacia vera L.) seedlings

F. Hojjat Nooghi and V. Mozafari

Department of Soil Science, College of Agriculture, Vali-e-Asr University of Rafsanjan, Iran

The effects of four salinity levels (0, 30, 60, and 90 mM NaCl) and three Ca levels (0, 0.5, and 1 mM Ca as Ca(NO3)2.4H2O) on chemical composition of pistachio seedlings Cv. Badami were studied in a completely randomized design (CRD) with four replications under greenhouse conditions. After 170 days, shoot and root Na, Ca, Fe, Mn, Cu, and Zn concentrations were measured. Results showed Ca applications increased shoot and root Ca concentrations. Salinity stress decreased shoot Ca concentration, while increased shoot and root total sodium uptake. It was found that the effects of salinity on the concentrations of Fe, Mn, Cu and Zn in pistachio seedlings were complex. The changes in Fe, Mn, Cu and Zn concentrations under saline conditions depended on the levels of salinity and the plant's organs. However, Ca had a significant effect on pistachio seedlings. The Ca application increased roots Fe, shoots Zn and shoots and root Cu concentrations in pistachio seedlings. The results suggest that supplementary Ca can reduce some adverse effects of high salinity on chemical composition of pistachio seedlings.

Pages 711-716 | Full Text PDF
Genetic diversity and population structure of wild rice, Oryza rufipogon from Northeastern Thailand and Laos

Preecha Prathepha

Department of Biotechnology, Faculty of Technology, Mahasarakham University, Khamriang sub-District, Kantarawichai District, Mahasarakham Province 44150, Thailand     

Northeastern Thailand and Laos are two most important habitats of the wild, (Oryza rufipogon). To examine the genetic diversity of this wild rice species, seven rice microsatellite markers were used to evaluate the genetic diversity of 94 accessions. In the entire sample a total of 83 alleles were detected, with an average of 11.85 allele per locus. The total gene diversity was an average of 0.733.  The Laos  population showed higher measures of genetic diversity (i.e., mean of allele number per locus, mean of genetic diversity, and mean of PIC value) than the northeastern Thailand population. Clustering analysis, using STRUCTURE to determine the true number of populations (k), reveals occurrences of different gene pools of wild rice among the examined populations. This observation support the hypothesis of the presence of subgroups in wild rice from northeastern Thailand and Laos.

Pages 717-723 | Full Text PDF
Regulation of ion homeostasis in rice subjected to salt and alkali stresses

Chunwu Yang, Na Zhao, Chunming Xu, Bao liu and Decheng Shi

Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun, Jilin Province, 130024 China

Alkali stress has shown a strong effect on K+/Na+ homeostasis than salt stress in many plants. In this study, rice seedlings were subjected to salt stress (NaCl:Na2SO4 = 9:1; pH 5.45) or alkali stress (NaHCO3:Na2CO3 = 9:1; pH 9.05). The contents of Na+, K+, and inorganic anions and organic acids in the stressed seedlings were then measured. Then, the expression of some genes related to K+/Na+ metabolism such as OsHKT, OsNHX and OsHAK families, the SOS pathway and OsAKT1 were assayed to investigate ion homeostasis and the regulative functions of these genes in rice alkali-tolerance. The results indicated that, alkali stress clearly reduced the contents of inorganic anions in rice, induced the massive influx of Na+ and a deficiency of K+ in roots, and disrupted Na+/K+ homeostasis and charge balance compared with salt stress (NaCl:Na2SO4 = 9:1; pH 5.45). Salt stress only has small effects on the OsHAK, OsNHX and OsHKT families and the OsAKT1 and SOS pathways in rice, but alkali stress strongly stimulated their expression in roots and shoots. These findings suggested that the rice OsHKT family, OsNHX family and SOS pathway might play important roles in protecting shoots from high-Na+ injury caused by alkali stress, especially in controlling Na+ transport from roots to shoots. Under alkali stress, the overexpression of OsHAKs and OsAKT1 might contribute to the release of K+ from roots to shoots or the K+ uptake by roots and maintain the potassium nutrition supply of shoots. The responses of these genes to alkali stress indicated that they might play important roles in rice alkali tolerance. Therefore, we propose that these genes have the potential for use in alkali tolerance and should be investigated further.

Pages 724-731 | Full Text PDF
Phenotypic and molecular marker distance as a tool for prediction of heterosis and F1 performance in sunflower (Helianthus annuus L.) under well-watered and water-stressed conditions

R. Darvishzadeh

Department of Agronomy and Plant Breeding, Urmia University, Urmia, Iran 
Institute of Biotechnology, Urmia University, Urmia, Iran

The aim of this study was to determine phenotypic and genotypic distances in parental lines of diallel population of sunflower, and to identify correlation between both distances with F1 performance, specific combining ability (SCA) and absolutely mid-parent heterosis. The morphological distance (Euclidean distance; EDs) and genetic distance (Jaccard`s distance; JD) among five sunflower parental lines were calculated based on 12 morphological traits and 160 amplified fragment length polymorphism (AFLP) markers in either well-watered and water-stressed conditions. The un-weighted pair-group method using arithmetic average (UPGMA) clustering algorithm, based on Euclidean and Jaccard distances, classified the studied parental lines into 3 groups. In both water treatment conditions, the high values of JD were correlated with high values of ED. Correlation results revealed that both of ED and JD had significant relation with F1 performance, SCA and heterosis for some traits in both water treatment conditions. Therefore, depending upon target trait, ED and JD could effectively be utilized in order to identify heterosis. Among studied genotypes, LR25 will be regard as a permanent parent in all possible pairwise crosses with other genotypes, to achieve optimum yield in both well-watered and water-stressed conditions.

Pages 732-738 | Full Text PDF
Influence of light and salt on the growth of alien invasive tropical weed Ageratum conyzoides

Peng Sun, Nitin Mantri, Michael Möller, Jinbo Shen, Zonggen Shen, Bo Jiang, Cuiqin Chen, Qin Miao, Hongfei Lu

College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004, China
School of Applied Sciences, Health Innovations Research Institute, RMIT University, Melbourne, Australia
Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh EH35LR, Scotland, UK
Department of Biological and Food Engineering, Changshu Institute of Technology, Changshu, Jiangsu 215500, China

The study reports the effects of salinity and light on growth of tropic ageratum, an annual invasive weed that is widespread in South China and Southeast Asia. Independent effect of light on leaf gas exchange and chlorophyll fluorescence, and combined effects of light and salinity on plant height, leaf area, chlorophyll content, soluble sugar, malondialdehyde (MDA), soluble protein and proline were measured over the growth period of ageratum. Low light availability decreased the light compensation point (LCP), maximum net photosynthetic rate (Pmax) and electron transport rate (ETR), but increased apparent quantum yield (AQY). High salinity combined with high light intensity reduced plant height, leaf area and chlorophyll content, and increased soluble sugar, MDA, soluble protein and proline contents. Factor analysis revealed that shade could alleviate the damage of salinity stress, but moderate and heavy shade have different effects depending on treatment duration. We conclude that light and salt are important factors controlling the growth of ageratum, and our results partly explain the distribution pattern of this species in the mudflat reclamated for agriculture in the southeast China coast. Further, this weed acclimatizes well to the various light and salinity environments, even high light intensity and severe salinity stresses. Thus, effective management should be taken to prevent further distribution and spread of this weed by environmentalists, ecologists and farmers.

Pages 739-748 | Full Text PDF
Physiological response of bread wheat (Triticum aestivum L.) to high temperature and moisture stresses

M. Ahmed, F.U. Hassan and M. Asif

Department of Agronomy, PMAS Arid Agriculture University Rawalpindi-46000, Pakistan
Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Centre, University of Alberta Canada

Water scarcity and temperature variability are major constraints of wheat productivity and food security in the context of climate change. The impact of temperature and water variability at anthesis of spring wheat was studied in field experiments conducted during 2008-09 & 2009-10. Five wheat cultivars viz; Chakwal-50, Wafaq-2001, GA-2002, NARC-2009 (NR-268 line in 2008) and Tatara were sown in a randomized complete block design with three replications. Physiological parameters i.e. net photosynthesis (An), transpiration rate (E), stomatal conductance (gs), intercellular carbon dioxide concentration (Ci) and stomatal resistance (rs) were recorded. The results indicate a reduction in An, gs, Ci and rs and an increase in E due to high temperature and moisture stress. Among genotypes, NARC-2009 produced highest grain yield and exhibited maximum photosynthetic rate which was positively related to gs, Ci and inversely related to rs and E. Rise in temperature and moisture stress at anthesis led to the reduction in photosynthesis, thereby, reducing biomass and grain yield. Therefore, genotypes having better physiological performance under abiotic stresses need to be considered for cultivation under changing environmental conditions. In our study, NARC-2009 performed best and we recommend its cultivation for areas having high temperature and moisture stresses. The values of all physiological attributes (An, E, gs, Ci and rs) were higher during the first year (2008-09) as compared to the second (2009-10) which was mainly due to the relatively low temperature and higher moisture availability during the first year.

Pages 749-755 | Full Text PDF
Respiratory enzyme activity and regulation of respiration pathway in seashore mallow (Kosteletzkya virginica) seedlings under waterlogging conditions

Jian Zhou, Xueliang Tian, Lifang Qiao, Pei Qin

Henan institute of science and technology, 453003 Xinxiang, China
Halophyte Research Lab of Nanjing University, 210093 Nanjing, China

We determined the enzyme activities involved in the aerobic and anaerobic respiration of Kosteletzkya virginica on the 0th, 10th, 20th, and 30th d of waterlogging to understand its respiratory characteristics. We also determined the enzyme activities on the 10th and 20th d of recovery after water drainage. Non-waterlogged seedlings were regarded as control during this experiment. All waterlogged seedlings were averagely divided into two parts after the formation of adventitious roots. The first and second treatment groups contain seedlings with retained and removed adventitious roots, respectively. The activities of mitochondrial enzymes, including pyruvate dehydrogenase, isocitrate dehydrogenase,
a-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, and cytochrome c oxidase, were lower in the two seedling groups than in the control. Furthermore, the adventitious root-removed seedlings exhibited the lowest mitochondrial enzyme activities during waterlogging. By contrast, an increase in the activity of fermentation enzymes, including alcoholic dehydrogenase (ADH), pyruvate decarboxylase (PDC), and lactate dehydrogense (LDH), was observed in the two treatments compared with the control. However, the activities of ADH, PDC, and LDH were higher in the adventitious root-removed seedlings than those in the adventitious root-retained seedlings. Subsequently, all enzyme characteristics in waterlogged seedlings were restored gradually during the recovery period. Enzyme activity was analyzed to calculate the amount of released electrons. The contribution of the tricarboxylic acid (TCA) cycle to the survival of stressed plants decreased, whereas that of lactic and alcoholic metabolisms increased during waterlogging. The contributions of TCA (27.8%) and alcoholic fermentation (36.3%) were obviously different from their corresponding control (36.1% and 31.0%, P ? 0.05) on the 30th d of waterlogging. The contribution rate of the TCA cycle in the adventitious root-retained seedlings was 6.7% and 5.9% higher (P ? 0.05) than that in the adventitious root-removed seedlings during this experiment. In conclusion, adventitious roots can sustain aerobic respiration in the mitochondria to help K. virginica overcome waterlogging.

Pages 756-762 | Full Text PDF
Development of sequence characterized amplified region (SCAR) marker for identifying drought tolerant sugarcane genotypes

Manoj Kumar Srivastava, Chang-Ning Li and Yang-Rui Li

Guangxi Crop Genetic Improvement and Biotechnology Lab, Guangxi Academy of Agricultural Sciences, Nanning 530007, Guangxi, P.R. China
College of Agriculture, Guangxi University, Nanning 530004, Guangxi, P.R. China

A sequence characterized amplified region (SCAR) marker was developed for screening drought tolerant genotypes in sugarcane. Of 150 RAPD decamer primers, used to identify polymorphism amongst five sugarcane genotypes (3 drought tolerant and 2 drought sensitive), 12 were found to be polymorphic. A 724 bp DNA fragment was amplified through PCR with primer OPAK 12 in drought tolerant genotypes ROC22 and GT 18, while it was absent in both sensitive genotypes. The DNA fragment was purified, cloned and sequenced. The DNA sequence of the RAPD marker OPAK 12724 was used to generate SCAR marker, which was used for screening 23 genotypes, of which 13 were tolerant and 10 were susceptible to drought stress. SCAR amplification in 12 tolerant sugarcane genotypes, including one tolerant wild species, showed 92% specificity of marker and confirmed its location at the same loci as that of RAPD marker OPAK 12724. The amplified fragment showed 91% homology with Saccharum officinarum cDNA sequences identified in SUCEST project. However, no other known gene sequence in GenBank was found to show 100% similarity with this sequence. Possibly, it might be related to some conserved sequences of sugarcane genome, still unidentified for their genetic function. High effectiveness in the detection of drought tolerant genotypes, as well as wild species of sugarcane, showed that this marker is appropriate in assisting selection of genotypes with drought tolerance.

Pages 763-767 | Full Text PDF
Australian Journal of Crop Science (AJCS)