November 2008 issue
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November 2008

Table of Contents

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Isolation and characterization of o-acetylserine (thiol) lyase, an enzyme of the cysteine biosynthetic pathway of vetch (Vicia sativa L.)

Annabelle U. Novero, Paul W.J. Taylor and Rebecca Ford
                                                                                           

Abstract
A putative o-acetylserine (thiol) lyase (OAS-TL; EC 2.5.1.47) gene was successfully cloned and characterized from vetch, Vicia sativa L. cv. Blanche Fleur.  The gene, named Voas-tl5 (GenBank Accession No. DQ456491) had a cDNA  length of 871 bp  with its open reading frame coding for a polypeptide of 68 amino acid residues. In semi-quantitative RT-PCR, mRNA transcription patterns revealed that the Voas-tl5 gene was highly transcribed in leaf, pod and seed tissues. Southern blot analysis indicated that Voas-tl5 was a single-copy gene.  Phylogenetic analysis revealed that the gene belonged to the Bsas 5 sub-group.  Further, the function of the gene was indicated by over-expression in the E. coli NK3 mutant strain, lacking the ability to synthesize cysteine.  The resultant transformed bacteria were able to grow on minimal media lacking cysteine. Understanding the molecular and biochemical properties of enzymes involved in the plant sulfate assimilation pathway, such as OAS-TL, can be applied to the future development of crops with greater agricultural productivity.

Keywords: Cysteine , vetch, amino acid biosynthesis, plant sulfur metabolism.

(Pages 96-104) Full text PDF



Asessment of genetic variation and relationships within the varieties of four Brassica species by RAPD markers


Sanchita Saha, Md. Rezwan Molla, Dulal Chandra  and Lutfur Rahman

                                                                                       
                      

Abstract:
This investigation was aimed at exploring the genetic diversity and relationship among nine Brassica varieties of four different species using Random Amplified Polymorphic DNA (RAPD) markers. In total, 59 reproducible DNA bands were generated by four arbitrarily selected primers, of which 58 bands were proved to be polymorphic. These bands have had range from 212 to 2272 bp in size. The highest proportion of polymorphic loci (37.29 %) was found in BARI sarisha-12 (B. rapa) and the lowest was 8.47 % for both in BINA sarisha-4 (B. napus) and Rai-5 (B. juncea). The highest intra-varietal similarity index was found in Alboglabra while the lowest value was found in BARI sarisha-12 which suggested that the former one is the least diversified variety and the later is the most diversified variety among the studied varieties. UPGMA cluster analysis indicated that nine accessions were capable of being classified into two major groups. One group consists of BARI sarisha-12, Agrani and Sampad of B. rapa (2n =20, AA); Daulot and Rai-5 of B. juncea (2n =36, AABB) and Alboglabra (B. oleracea, 2n =18 CC) where Daulot and Rai-5 showed the lowest genetic distance of 0.049. Another group contains BINA sarisha-4, BINA sarisha-5 and BARI sarisha-13 all of which represent B. napus where BINA sarisha-5 and BARI sarisha-13 showed genetic distance of 0.071. The highest level of genetic distance was found between the varieties of BINA sarisha-4 and Rai-5 followed by the varietal pairs BINA sarisha-4 and Daulot.

Key words: Brassica, genetic distance, genetic variation, RAPD markers relationship.

(Pages 105-114) Full text PDF

                                                                                                                                                                       
Integrating host plant resistance and chemical control in the management of Cowpea pests

Paul B Tanzubil, M Zakariah and A Alem

Abstract
Studies were conducted at Manga in the Sudan Savanna zone of Ghana to evaluate the potential of integrating host plant resistance with chemical control in the management of key insect pests of cowpea, Vigna unguiculata. None of the improved varieties tested showed significant and consistent resistance to the key pests and there were no significant interaction effects between varieties and spray regime. The local varieties, Omondaw and Bengsogla however supported relatively fewer Megalurothrips sjostedti  and pod sucking bug (PSB) populations and thus suffered significantly lower damage (shriveled pods) and produced better  yields under no insecticide protection than the improved varieties. This was particularly evident in 2005 when the pest population was very high. Spraying the crop with Karate during the reproductive phase produced better results than with neem extracts. Nevertheless, applying neem seed extracts twice and four times increased grain yield by 45 - 54 % and 126 - 144 % respectively over the control, confirming their potential in cowpea Integrated Pest Management.

Key words : Cowpea, Vigna unguiculata, chemical control, host plant resistance, Neem extracts.

(Pages 115-120) Full text PDF   


                                                                                                               
Comparative study on the induction of defense related enzymes in two different cultivars of chickpea (Cicer arietinum L) genotypes by salicylic acid, spermine and Fusarium oxysporum f. sp. ciceri

S. Raju, S.K. Jayalakshmi, K. Sreeramulu

Abstract 
Induction of some defense related enzymes and phenolics in roots and shoots of two different genotypes of chickpea cultivars which were susceptible (L550) and resistant (ICCV10) to wilt disease treated  with salicylic acid, spermine (Spm), SA+Spm and Fusarium oxysporum f. sp. ciceri was investigated. Higher levels of polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL), -1, 3-glucanase (PR-2) and phenolics were observed in roots and shoots of resistant cultivar than that of susceptible cultivar on treatment with elicitors and pathogen. However, no major changes were observed in susceptible cultivar after the treatments. -1, 3-glucanase is constitutively present and is further induced in roots and shoots of resistant  cultivar by F. oxysporum f. sp. ciceri. No induction of -1, 3-glucanase was observed in susceptible cultivar. The structural changes during disease progression were observed by histochemical staining. However, the pathogen invasion was more in susceptible cultivar compared with resistant cultivar. Further, the invasion was restricted in roots of resistant cultivar treated with SA. These results suggest that induction of defense proteins and accumulation of phenolics might have contributed to restrict the invasion of F.oxysporum f. sp. ciceri, in resistant cultivar ICCV10.

Keywords:
Polyphenoloxidase, phenylalanine ammonia-lyase, salicylic acid,   spermine, chickpea, Fusarium oxysporum f. sp. ciceri. 

(Pages 121-140) Full text PDF

                                                                                                               
Hybrid authentication in upland cotton through RAPD analysis

Muhammad Amjad Ali, Muhammad Tahir Seyal, Shahid Iqbal Awan, Shahid Niaz,
Shiraz Ali and Amjad Abbas

Abstract
The investigation pertaining to the hybrid identification in Gossypium hirsutum L. through Random amplified polymorphic DNA (RAPD) analysis was conducted on 3 genotypes (CIM-511, SLS1 and Paymaster) and their hybrids (SLS1 CIM-511, Paymaster CIM-511, Paymaster SLS1) at University of Agriculture, Faisalabad, Pakistan during 2007. Sixteen RAPD markers developed by Genelink, Company were utilized for this purpose. DNA was extracted from young leaves of the plants and quantified by spectrophotometer and subjected to RAPD analysis. These 16 primers amplified a total of 518 fragments in the parents and hybrids and out which 76 loci were polymorphic. On an average of 7.13 bands per primer were observed with maximum of eight bands and minimum of six. The primer GLG-17 was found to produce 87.5 % polymorphic fragments. The lowest polymorphism (42.85%) was seen in primer GLH-2. Comparison of the RAPD banding pattern of the parents with the respective hybrids clearly identified genuine hybrids. The cluster dendrogram based on similarity matrix obtained by unweighted pair group method using arithmetic average (UPGMA), also revealed the same results. This study suggested that RAPD analysis can be utilized for both reliable and less time consuming identification of hybrids.

Key words: Gossypium hirsutum; Hybrid authentication; RAPD analysis

(Pages 141-149) Full text PDF
                                                                                                                
Assessment of different crop nutrient management practices for yield improvement


Sajid Ali, A. Riaz Khan, Ghazal Mairaj, M. Arif, Mehwish Fida and Saiqa Bibi


Abstract
Food security could only be attained with increasing crop productivity. One of the major crop productivity constraints is the unavailability of crop nutrients. Both macro and micro nutrient deficiencies have been reported in most of the soils, which could be provided through various nutrient management practices. Different nutrient application measures were studied for their impact on crop yield and yield-related parameters in a series of experiments, conducted at agricultural research farm, NWFP Agricultural University Peshawar, Pakistan from 2004 through 2007. FYM application was observed to improve crop growth and yield of different wheat cultivars. Nutrient seed priming resulted in better early growth of maize. At field level, nutrient seed priming improved performance of wheat. Similarly for maize crop, nutrient seed priming resulted in more number of cobs plot-1, grains cob-1, 1000-grain weight and biological yield of maize crop even at lower soil application. Soil application of P improved yield and yield components. Better results were obtained from combined use of priming and soil P application.  Foliar application of macro and micro nutrients also produced better crop yield and yield components. Similarly, foliar application of micro nutrients (zinc and boron) improved yield over two years. Our results show that all of these crop nutrients management practices has a positive impact on crop performance and call for an integrated approach of crop nutrient management. Such integrated approach must be evaluated at farm level for their economic impact. Adoption of integrated crop nutrient management techniques could be more economical and environmental friendly to achieve higher yields and thus food security.
                        
(Pages 150-157) Full text PDF

                                                                                                               
Plant characteristics, growth and leaf yield of Aloe vera as affected by organic manure in pot culture

Mirza Hasanuzzaman, Kamal Uddin Ahamed, 3K.M. Khalequzzaman, A.M.M. Shamsuzzaman and Kamrun Nahar


Abstract
A pot experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka, Bangladesh to evaluate the effect of different amount of manures on the leaf and plant characteristics as well as yield of Aloe vera. There were 8 different treatments viz., T1 = 100% soil (control), T2= 50% cowdung + 50% soil, T3= 25% cowdung + 75% soil, T4= 10% cowdung + 90% soil + urea, T5= 10% cowdung + 90% soil, T6=5% cowdung + 95% soil + urea, T7= 5% cowdung + 95% soil, T8=soil + urea. It was observed that the plant produced highest number of leaves and maximum leaf weight, maximum leaf breadth, total leaf area as well as length and breadth of largest leaves with application of 50% cowdung + 50% soil (T2). Different plant characters such as weight of tiller, stem and root as well as root length was also found to be highest with T2 treatment over control (100% soil). The growth rate of leaves also significantly affected by different manure treatments where maximum effect was noticed at early stages with all the treatment. It was revealed that urea had a little effect on plant character of Aloe vera over organic manure (cowdung).

Key words
:
Aloe vera, cowdung, urea, leaf growth
                                                                                                       
(Pages 158-163) Full text PDF

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