Muhammad Bashir

Genetic relationship in Vigna mungo (L.) Hepper and V. radiata (L.) R. Wilczek based on morphological traits and SDS-PAGE

Thirty seven diverse genotypes of Vigna mungo and three of V. radiataresembling to V. mungo for seed characters were studied to determine the extent of genetic variation based on morphological characters. In addition, 4black seeded genotypes in each species and8 green seeded V. radiata genotypes were included for SDS-PAGE analysis. Seed proteins were analyzed through slab type SDS-PAGE. High variance was observed for plant height, days to flowering, days to maturity, number of branches/plant, number of pods/plant, pod length, seeds per pod,biomass yield/plant, grain yield/plant and harvest index (%) during 2 consecutive years. First four components of PCA with eigenvalues >1 contributed 78.7 and79.1% of the total variance amongst 40genotypes during 1998 and 1999. The populations with high PC1 values were expected to be high yielding characterised by earlyness, high seed weight and harvest index, all traits strictly related to reproductive phase. Four clusters of genotypes were observed during both the years and genetic diversity was in association for both the years. Based on SDS-PAGE, specific bands were suggested to be used for identifying Vigna radiatafrom mixed germplasm with Vigna mungo. The SDS-PAGE proved to be a powerful tool for differentiating Vigna radiata and Vigna mungo, whereas a low level inter-specific genetic diversity was observed and no clear differentiation was observed both for agronomic characteristics and for geographical origin.

Cowpea aphid-borne mosaic potyvirus: a review

Cowpea aphid-borne mosaic potyvirus (CABMV) is a cosmopolitan, economically significant seed-borne virus of cowpea. It can cause a yield loss of 13 - 87% under field conditions depending upon crop susceptibility, virus strain and the environmental conditions. CABMV has spread world-wide through the exchange of virus-infected germplasm material. The virus-infected seed provides the initial inoculum and aphids are responsible for the secondary spread of the disease under field conditions. The virus symptoms vary with the cowpea genotype and virus strain. Excellent sources of resistance are available for the breeding of resistant cultivars. Resistance in cowpea is conferred by either a dominant or a recessive gene. Enzyme-linked immunosorbent assay (ELISA) is the most appropriate method for the detection of the virus in the seed or plant tissue for seed certification programmes. Production of virus-free seed is another control option. Given the significance of the disease and the large area under cowpea cultivation in the world, we review knowledge of various aspects of the disease.

Diseases of major pulse crops in Pakistan—a review

Abstract The major pulse crops of Pakistan are chickpea, lentil, mungbean, and urdbean. Diseases are a constant threat and often a limiting factor in the cultivation of pulse crops. Chickpea is attacked mainly by blight, wilt and root rot complex. The main diseases of mungbean and urdbean are yellow mosaic virus (YMV), leaf crinkle virus (LCV), cercospora leaf spot, bacterial blight and charcoal rot. Lentil is attacked by rust, wilt and blight. Details are given of the symptoms, distribution and control of the diseases of economic importance.

Sources of genetic resistance in cowpea (Vigna unguiculata (L.) Walp.) to cowpea aphid-borne mosaic potyvirus

Fifty-one cowpea (Vigna unguiculata (L.) Walp.) genotypes were tested by mechanical inoculation with seven geographically diverse isolates of cowpea aphid-borne mosaic potyvirus to identify resistant sources. Of 51 genotypes three, TVu-401, TVu-1582 and TVu-1593 were found immune to all the seven isolates. Forty-five genotypes gave different reactions to individual isolates. Several immune, resistant and tolerant genotypes against each isolate were identified. A considerable evidence of pathogenic variability among the virus isolates was also observed.