Australian Journal of Crop Science

Characterization of a gene encoding for dihydrodipicolinate synthase from rice

Fri, 20 Aug 2010 19:18:04 GMT

Md.Shafiqul Islam Sikdar, Jung-Sup Kim

Abstract

Dihydrodipicolinate synthase (DHDPS, EC 4.2.1.52) is a key enzyme in lysine biosynthesis in the aspartate family pathway of plants
and microorganisms. The dapA gene encoding for DHDPS has been reported in many bacteria and plants and was utilized to enhance
the level of lysine in cereal crops. In this study, we describe the functional analysis and characterization of a gene encoding for
DHDPS from rice (OsDHDPS). Analysis of the OsDHDPS sequence showed a full-length open reading frame consisting of 380 amino
acids, which encoded for a protein of approximately 41.4 kDa. The predicted amino acid sequence of OsDHDPS is highly homologous
to those of other DHDPS enzymes from bacteria and plants. The OsDHDPS expression in a dapA mutant of Escherichia coli showed
that the gene was functionally capable of complementing the mutant. These results indicated that the OsDHDPS encoded for a protein
in dihydrodipi- colinate synthase in rice.

Isolation and characterization of some important fungi from Echinochloa spp. the potential agents to control rice weeds

Fri, 20 Aug 2010 19:17:36 GMT

Mohammad Reza Safari Motlagh

Department of Plant Pathology, Faculty of Agriculture, Islamic Azad University, Rasht Branch, Rasht, Iran

Abstract

Barnyard grass (Echinochloa spp.) is the most important weeds in rice fields. Some fungal pathogens can potentially be used as
biological agents for the control and management of these weeds. For this reason, two pathogenic fungal species were isolated and
characterized from naturally infected Echinochloa species. Morphological characters of isolates were studied in order to identify the
taxonomy. According to the results, isolates were belonged to Alternaria alternata (Fries) Keissler, and Fusarium equiseti (Corda)
Saccardo. Pathogenicity test of isolates was done in desiccators, and revealed the pathogenicity level of the species and their ability
to cause leaf blight on Echinochloa spp. The results indicated that not only the symptoms but also the virulence of these two fungi are
significantly different.

Prediction of banana quality during ripening stage using capacitance sensing system

Fri, 20 Aug 2010 19:16:47 GMT

M. Soltani, R. Alimardani, M. Omid

Abstract

Capacitive property of banana fruit was studied in order to develop a rapid and non-invasive ripening assessment method to control
their ripening treatment. A sine wave frequency generator with parallel plates capacitor sample was used to span the difference in
capacitance caused by the introduction of a banana fruit into the sensor. Banana fruits were submitted to measurement before
ethylene treatment on first day and after treatment for five days. Relative permittivity was correlated with quality parameters of
banana fruit. Green-ripe banana fruits have larger permittivity than the full-ripe ones, the permittivity of which was decreased as a
result of the ripening stage. Quadratic regression had higher prediction power of the equations than linear regression. Experiments
indicated that the best frequency of sine wave was1 MHz. Permittivity at this frequency changed from 1.7433 for green-ripe banana
fruits to 1.6431 for full ripe ones after a five-day period.

The influence of osmotic concentration of media on the growth of Sago Palm (Metroxylon sagu Rottb.) in vitro

Fri, 20 Aug 2010 19:16:26 GMT

Annabelle Novero, Aileen Grace Delima, Joan Acaso and Leah Mae Baltores

Abstract

This study investigated the role of osmotic potential of media on the early growth stages of sago palm in vitro. There were significant
effects on the growth rate of explants after four weeks of culture under different sucrose and D-sorbitol combinations. A modified
Murashige and Skoog (MS) medium supplied with 22.5 g sucrose and 7.5 g sorbitol which created a low osmotic potential environment
(-0.457 MPa) had significant effects on the increase in weight of explants. This osmotic potential was found optimal for the initial
growth of sago palm explants in vitro. In contrast, explants cultured in intermediate osmotic potential media (-0.380 MPa) obtained
little increase in weight. Results suggested that owing to the sago palm’s ecology where it is highly adapted to flooding even by saline
water, explants likewise prefer a low osmotic potential in in vitro culture.

Fracture resistance of wheat grain as a function of moisture content, loading rate and grain orientation

Fri, 20 Aug 2010 19:15:14 GMT

A.Gorji, A. Rajabipour, H. Tavakoli

Abstract

In this research, fracture resistance of wheat grain was measured in terms of grain rupture force and energy. The wheat grains were
quasi-statically loaded in horizontal and vertical orientations with moisture content in three levels: 7.8%, 15%, and 20%; and loading
rate in two levels: 5 and 10 mm min-1. Based on the results obtained, the force required for initiating grain rupture decreased from
77.68 to 35.7 N and 152.11 to 63.99 N, and the energy absorbed at grain rupture increased from 17.8 to 24.34 mJ and 19.32 to 28.35
mJ, with increase in moisture content from 7.8 to 20% d.b., for vertical and horizontal orientations, respectively. This showed that
grains are more flexible in horizontal orientation. Rupture force requires less energy under vertical loading than horizontal loading.
Maximum energy absorbed was found to be 32.40 mJ for grain with 20% moisture content under horizontal loading and 5 (mm min-1)
loading rate. The highest mechanical strength (162.61 N) is related to grain with a moisture content of 7.8% under horizontal loading
and 5 (mm min-1) loading rate. Energy absorbed by the seeds decreased as increased loading rate.

Management of Phelipanche aegyptiaca Pomel. using trap crops in rotation on tomato (Solanum lycopersicom L.)

Fri, 20 Aug 2010 19:14:10 GMT

Sirwan Babaei, Hassan Alizadeh, Mohammad Reza Jahansouz, Hamid Rahimian Mashhadi and Mehdi Minbashi Moeini

Abstract

One of the most susceptible hosts of the Phelipanche aegyptiaca (pers.) Pomel is tomato. Broomrape causes yield loss in tomato due
to severe infestations in many regions of Iran. A study was conducted to evaluate the effect of some trap crop on reducing Ph.
aegyptiaca damage in tomato. Trap crops consisting of Egyptian clover, sesame, mungbean, common flax, brown Indianhemp,
cotton, pepper and black-eyed pea were studied during 2008 and 2009. Through the first year, trap crops were cultivated in pots and
in the next year, tomato was transplanted into those pots. Sesame, brown Indianhemp, common flax and black-eyed pea decreased
broomrape biomass by 86, 85.3, 75.2, and 74.4%, respectively. Reducing broomrape biomass caused increases in the tomato yield.
Meanwhile, sesame, brown Indianhemp, Egyptian clover and mungbean increased total biomass of tomato by 71.4, 67.5, 65.5, and
62.5 %, respectively. It was found that these plants have a great potential to reduce broomrape damage and they can be used in
rotation in broomrape infested fields.

Expression of a gene encoding acetolactate synthase from rice complements two ilvH mutants in Escherichia coli

Fri, 20 Aug 2010 19:13:40 GMT

Md. Shafiqul Islam Sikdar, Jung-Sup Kim

Abstract

Acetolactate synthase (ALS) is a thiamine diphosphate-dependent enzyme in the biosynthetic pathway leading to isoleucine, valine
and leucine in plants. ALS is the target of several classes of herbicides that are effective to protect a broad range of crops. In this
study, we describe the functional analysis of a gene encoding for ALS from rice (OsALS). Sequence analysis of an EST from rice
revealed that it harbors a full-length open reading frame for OsALS encoding a protein of approximately 69.4 kDa and the N-terminal
of OsALS contains a feature of chloroplast transit peptide. The predicted amino acid sequence of OsALS is highly homologous to those
of weed ALSs among plant ALSs. The OsALS expression showed that the gene was functionally capable of complementing the two ilvH
mutant strains of Escherichia coli. These results indicate that the OsALS encodes for an enzyme in acetolactate synthase in rice.

Agrobacterium tumefaciens-mediated transformation of the isopentenyltransferase gene in japonica rice suspension cell culture

Fri, 20 Aug 2010 19:13:10 GMT

Alina Wagiran, Ismanizan Ismail, Che Radziah Che Mohd Zain, and Ruslan Abdullah

Abstract

The global population is expected to grow from 6 to 8 billion people and rice consumers are projected to increase by 1.8% annually
until 2020. Hence, rice production must be increased between 25-45% to fulfill the growing need. Efforts to genetically improve rice
for high quality grains are extensively being carried out. The cloning vectors containing the ipt gene driven by the glutenin high
molecular weight promoter were successfully constructed in pCAMBIA1305.2 and transformed into A. tumefaciens LBA4404, which
were then used in the genetic transformation of a japonica suspension cell culture. The highest percentage of transformation
frequency based on GUS activity was 93% in the variety Hayahishiki and 77% in Nippon Bare when 200 µM AS was included in the
inoculation media. The highest percentage of GUS activity was 30% in the variety Fujisaka 5 in the presence of 100 µM AS. There was
no difference in terms of GUS expression when different inoculation times were tested. A twenty minute post-dehydration treatment
led to the highest GUS activity in all varieties tested. The inclusion of AS is critical and very important to obtain successful
transformation. The sensitivity and response of suspension cells to different hygromycin concentrations was varied among the
varieties tested. Selection of transformed cells in N6 liquid media containing 25 mg/L hygromycin proved to be easy and facilitated
the removal of non-transformed cells. PCR analysis has shown that 2.3% of the putatively transformed rice variety Nippon Bare
contained the ipt gene, while only 2.0% for the Hayahishiki variety. The finding of this research shows the potential for rice
suspension cells in regeneration and genetic transformation systems by providing continuous explants and could be used as tools to
obtain large scale transformation of rice plants via Agrobacterium tumefaciens.

Predicting hybrid performances from interploidy crosses in Musa species

Fri, 20 Aug 2010 19:12:33 GMT

Oselebe, H.O., I.U. Obi and M.I. Uguru

Abstract

Models for predicting hybrid performance of progenies from crosses have been developed and genetic parameters for different Musa
populations would have to be estimated from experimental data. Determination of these parameters would be dependent on defining
the relationships of progeny to parents in different crosses and identifying parental contributions to offspring. The objective of this
work was to estimate genetic relationships based on meiotic mechanisms in parents, and redefine models for predicting hybrid
performance for different inter-ploidy crosses in Musa. The study was carried out at the High Rainfall Station of the International
Institute of Tropical Agriculture in Onne (4º43’ N, 7º01’E, 10 m above sea level). A breeding population of approximately 2150
individuals was developed from crosses involving tetraploid (4x) and diploid (2x) parental lines. The diameter of pollen grains from
parental lines was measured under a light microscope, while the ploidy status of the breeding populations was determined by flow
cytometry (FCM) analysis. Tetraploid lines had a higher mean pollen diameter than diploids. However, there were no differences
between the diameter of “n” pollen of the 4x and 2x lines. 4x - 2x crosses produced predominantly 3x progenies, whereas 2x – 4x
crosses gave mostly 2x progenies, suggesting a pattern of unequal contribution of the parents with respect to 3x progeny from 4x –
2x crosses, but equal parental contribution to 2x progeny from 2x – 4x crosses. The knowledge of parental contributions to progeny
was used to redefine models for predicting hybrid performance from interploidy crosses in Musa.

Saline irrigation water management strategies for better yield of safflower (Carthamus tinctorius L.) in an arid region

Fri, 20 Aug 2010 19:12:00 GMT

Mohammad Feizi, Mohammad A. Hajabbasi and Behrouz Mostafazadeh-Fard

Abstract

To determine the effects of irrigation water salinity and irrigation management on Safflower yield, a field experiment was conducted
in Isfahan province, central part of Iran. Three irrigation water salinity levels of 3.4, 8.8 and 11.2 dS m-1, two irrigation water
managements and two leaching levels of without leaching and with leaching including leaching levels of 6, 17, and 28.5 %, were used
in a completely randomized block design, arranged as Split-Split plots with four replications for each treatment. The results showed
that as the irrigation water salinity increases the yield components such as seed yield, biomass yield (dry weight), number of plant
per hectare, 1000- seed weight, plant height, number of capitula per plant and capitula weight per plant decreases significantly. The
irrigation water management treatment of irrigating with water salinity of 3.4 dS m-1 up to plant emergence, thereafter, applying the
high irrigation water salinity levels significantly increased the yield components. Also, Leaching application caused a significant
increase in the yield and yield components. The salinity threshold value of 6.4 dS m-1 was obtained for safflower seed yield.

Determining the most important features contributing to wheat grain yield using supervised feature selection model

Fri, 20 Aug 2010 19:11:28 GMT

Ehsan Bijanzadeh, Yahya Emam, Esmaeil Ebrahimie

Abstract

A supervised feature selection algorithm was applied to determine the most important features contributing to wheat grain yield. Four
hundreds seventy two fields (as records) from different parts of Iran which were different in 21 characteristics (features) were
selected for feature selection analysis. Selection of the wide range of features, including location, genotype, irrigation regime,
fertilizers, soil textures, physiological attitudes, and morphological characters, provided the opportunity of precise simultaneous study
of a large number of factors in wheat grain yield topic by hand of data mining. The grain yield of each record assumed as target
variable. The feature selection algorithm selected 14 features as the most effective features on grain yield. These features included
culture type, location, soil texture, 1000 kernel weight, nitrogen supply, irrigation regime, biological yield, organic content of the soil,
the amount of rainfall, genotype, plant height, and spike number per unit area. Interestingly, growing season length and plant density
were the second most important features for wheat grain yield. Based on the feature selection model, culture type, as dryland
farming or irrigated, severely affected wheat grain yield. The soil pH had a marginal effect on wheat grain yield. The results of this
investigation demonstrated that feature classification using feature selection algorithms might be a suitable option for determining the
important features contributing to wheat grain yield, providing a comprehensive view about these traits. This is the first report in
identifying the most important factors on wheat grain yield from many fields using feature selection model.

Effects of methanol on sugar beet (Beta vulgaris)

Fri, 20 Aug 2010 19:10:56 GMT

Nadali, F. Paknejad, F. Moradi, S. Vazan, M. Tookalo, M. Jami Al-Ahmadi, Alireza Pazoki

Abstract

In order to evaluate the effects of methanol on sugar beet quality and yield, a field study was conducted at Research Station of
Islamic Azad University of Karaj, Iran, during 2008-2009. Aqueous methanol solutions with 0 (control), 7, 14, 21, 28 and 35% (v/v)
concentrations were sprayed on foliage parts of sugar beet three times during growth season with two week intervals. The first foliar
application was done at 80 days after planting. After 190 days, plants were harvested, and the fresh weight of root and leaf, sugar,
and white sugar yields, the relative content of molasses, sugar and white sugar, and the content of Na, K, and N in roots were
measured. Results indicated that there was a significant difference (p<0.01) between control plants and plants with methanol
treatment in the fresh weight of root, leaf, sugar, and white sugar. Foliar application of 21% methanol solution increased root and leaf
fresh weights and sugar yield. The plants with 14% (v/v) methanol application had the maximum white sugar yield (9.28 ton/h). The
other parameters were not affected by methanol application. This study indicates that foliar application of 14-21% (v/v) methanol
increase sugar yield of sugar beets.

Heterosis and combining ability analysis for oil yield and its components in rapeseed

Fri, 20 Aug 2010 19:10:24 GMT

N. Sabaghnia, H. Dehghani1, B. Alizadeh, M. Mohghaddam

Abstract

The occurrence of heterosis for oil percent, oil yield and some yield components has been studied in 36 F1 combinations derived from
nine parental genotypes (from France, Denmark, Sweden, Germany and Iran) of rapeseed according to a diallel design. In the 2008
and 2009 seasons the Fl hybrids and the parental genotypes were sown according to simple lattice design. In both years, the mean
squares due to general combining ability (GCA) and specific combining ability (SCA) were also highly significant. SCA genetic
variances were greater than GCA and more important for the traits, showing the predominance of non-additive gene action. The
results of combined analysis over year indicated SCA × year interactions were significant sources of variation in the inheritance of all
traits while GCA × year interactions were significant only for number of seeds per pod of plant and oil percent. Significant positive
heterotic effects including mid-parent and high parent heterosis were observed for all the triats studied but for different number of
crosses. Parental genotypes with best GCA (Opera and Talaye) and its utilization as one of the parents produced excellent hybrid
combinations having valuable SCA determination for oil yield. F1 hybrids like Orient × Zarfam, Orient × Talaye, Opera × Talaye
performed well in GCA and SCA determination and heterosis. This outcome could be a good indicator to identify the most promising
genotypes to be utilized either as F1 hybrids or as a resource population for further selection in rapeseed improvement.

Effect of organic and inorganic fertilizers on grain yield and protein banding pattern of wheat

Fri, 20 Aug 2010 19:09:47 GMT

Tayebeh Abedi, Abass Alemzadeh and Seyed Abdolreza Kazemeini

Abstract

In order to evaluate the effects of different levels of inorganic (0, 80, 160 and 240 kg Nitrogen ha-1) and organic (30 and 60 Mg
municipal waste compost ha-1) fertilizers on wheat grain yield, gluten content, protein variability and protein banding pattern on
polyacrylamide gel in different growth stages of irrigated wheat, a field experiment was conducted at research station of the School of
Agriculture, Shiraz University at Bajgah in 2007. Results indicated that the highest wheat grain yield was achieved when the plants
were fertilized with 160 kg N ha-1 and 30 Mg compost ha-1. Among yield components, spikes plant-1, seeds spike-1 and 1000 kernels
weight were significantly increased with increasing the level of nitrogen. However, there was no significant difference between 160
and 240 kg N ha-1. There was no significant effect of N fertilization on seed protein and gluten content, however the highest amount
of seed protein was obtained in 60 Mg compost ha -1 at all levels of nitrogen. The SDS-PAGE was performed to investigate
differences between proteins banding pattern in different growth stages under different levels of N and compost. Protein banding
pattern showed no polymorphism in tillering and stem elongation stages. However, in ear emergence in 160 kg N ha-1 and in the all
compost levels, density of a 50 kDa band was increased specifically in 60 Mg compost ha-1. Furthermore, seed water soluble
proteins, Albumin and Globulin, showed no polymorphism. All in all, it is possible to obtain maximum grain yield, protein and gluten,
just in 160 kg ha-1 nitrogen level. Thus, it shows the positive impact of compost application on reduction of chemical fertilizer use.

Stress induced phosphate solubilization by Arthrobacter sp. and Bacillus sp. isolated from tomato rhizosphere

Fri, 20 Aug 2010 19:09:04 GMT

Samiran Banerjee, Rakhi Palit, Chandan Sengupta, and Dominic Standing

Abstract

The importance of rhizospheric microbial phosphate solubilization has now been well documented. However, the performance of these
microbes is greatly affected by various environmental stresses such as salt stress, pH stress, temperature stress etc. In this study,
two stress tolerant phosphate solubilizing rhizobacteria Arthrobacter sp. and Bacillus sp. have been isolated from tomato rhizosphere
and characterized with various morphological and biochemical tests. Phosphate solubilizing bacteria were screened on the basis of
their phosphate solubilization and strains with high phosphate solubilizing ability were then tested against wide range of temperature,
pH, and salt stresses. Their ability to solubilize other insoluble phosphates, such as ferric phosphate (FePO4) and aluminum phosphate
(AlPO4) was also studied. In addition to phosphate solubilizing ability these strains also demonstrated various plant growth promoting
and biocontrol activities including indole acetic acid (IAA) production. These two strains have the potential to be used as plant growth
promoting rhizobacteria (PGPR).