Genetic Analysis of Effect of Heat Stress on Genomic DNA from Cowpea ( Vigna unguiculata (L) Walp.)

Aims: Genetic analysis was used to study the effect of heat st ress on young seedlings of cowpea ( Vigna unguiculata (L) Walp.). Study Design: Four different colors of cowpea seeds (white, dirty w hite, deep brown and light brown) were obtained from GeneBank of International Institute of Tropical Agriculture (IITA) Ibadan, Nigeria. Seeds from each of the cowpea four colors we re first pre-germinated and young seedlings subjected to DNA extraction. Extracted DNA subjected to different temperature treatments at 75°C and 100°C for one hour and control not heated. Place and Duration of Study: Department of Chemical Sciences Afe Babalola University Ado Ekiti, Nigeria between January 2015 and June 2015. Methodology: UV wavelength absorption spectrum analysis (A 200 – A 960 ) was carried out on control DNA and DNA heated at 75°C and 100°C respectively. Cl uster analysis of optical density (OD) data was carried out to establish the relationship between co ntrol DNA and heat treated DNA (75°C and 100°C). Results: DNA concentrations of Vigna unguiculata (L) Walp. were between 0.40 to 1.15 mg/ml, 0.33 to 0.84 mg/ml, and 0.26 to 0.89 mg/ml for control a nd heat treatments of 75°C and 100°C respectively. DNA UV absorption spectra of control and heat treatments of 75°C and 100°C were generally different due to differential UV wavelengt h absorption. Cluster analysis revealed three different clusters (cluster 1, cluster 2 and cluster 3) among control DNA and heat treated DNA. Cluster 1 comprised of V1-control, V1-75°C and V1-10 0°C, with V1-75°C and V1-100°C having similar characters. Cluster 2 was made up of V4-control, V4-75°C and V4-100°C, with V4-75°C and V4-100°C having the same characters. Cluster 3 was largel y characterized by dissimilar DNA extracts of V3-75°C, V2-control, V3-100°C, V2-100°C, V 3-control and V2-75°C. Conclusion: Genetic diversity among individual Vigna unguiculata (L) Walp. accession DNA as obtained in this study could possibly be as a result of variations in heat tolerance among dissimilar cowpea genomic composition

Effects of biofertilizer containing N-fixer, P and K solubilizers and AM fungi on maize growth: A greenhouse trial.

An in vitro study was undertaken to evaluate the compatibility of indigenous plant growth promoting rhizobacteria (PGPR) with commonly used inorganic and organic sources of fertilizers in tea plantations. The nitrogenous, phosphatic and potash fertilizers used for this study were urea, rock phosphate and muriate of potash, respectively. The organic sources of fertilizers neem cake, composted coir pith and vermicompost were also used. PGPRs such as nitrogen fixer; Azospirillum lipoferum, Phosphate Solubilizing Bacteria (PSB); Pseudomonas putida, Potassium Solubilizing Bacteria (KSB); Burkholderia cepacia and Pseudomonas putida were used for compatibility study. Results were indicated that PGPRs preferred the coir pith and they proved their higher colony establishment in the formulation except Azospirillum spp. that preferred vermicompost for their establishment. The optimum dose of neem cake powder

Identification and potential use of RAPD markers linked to yam mosaic virus resistance in white yam (Dioscorea rotundata)

Resistance to Yam mosaic virus (YMV) in tetraploid white yam (Dioscorea rotundata) is inherited differentially as a dominant and recessive character. Elite D. rotundata breeding lines with durable resistance to YMV can be developed by pyramiding major dominant and recessive genes using marker assisted selection (MAS). The tetraploid breeding line, TDr 89/01444, is a source of dominant genetic resistance to yam mosaic disease. Bulked segregant analysis was used to search for random amplified polymorphic DNA (RAPD) markers linked to YMV resistance in F1 progeny derived from a cross between TDr 89/01444 and the susceptible female parent, TDr 87/00571. The F1 progeny segregated 1:1 (resistant: susceptible) when inoculated with a Nigerian isolate of YMV, confirming that resistance to YMV in TDr 89/01444 was dominantly inherited. A single locus that contributes to YMV resistance in TDr 89/01444 was identified and tentatively named Ymv-1. Two RAPD markers closely linked in coupling phase with Ymv-1 were identified, both of which were mapped on the same linkage group: OPW18850 (3.0 centiMorgans [cM]) and OPX15850 (2.0 cM). Both markers successfully identified Ymv-1 in resistant genotypes among 12 D. rotundata varieties and in resistant F1 individuals from the cross TDr 93-1 ´ TDr 87/ 00211, indicating their potential for use in marker-assisted selection. OPW18850 and OPX15850 are the first DNA markers for YMV resistance and represent a starting point in the use of molecular markers to assist breeding for resistance to YMV