ACTA BIOLOGICA CRACOVIENSIA Series Botanica 47/2: 69–75, 2005 DIVERSITY OF AGRONOMIC TRAITS AND TOTAL SEED PROTEIN IN BLACK GRAM VIGNA MUNGO (L.) HEPPER ABDUL GHAFOOR AND ZAHOOR AHMAD National Institute of Agri Biotechnology and Genetic Resources, National Agricultural Research Centre, Islamabad, Pakistan Received July 29, 2004; revision accepted June 27, 2005 This study evaluated agronomic traits of 111 genotypes of black gram Vigna mungo (L.) Hepper, mainly from Pakistan, to determine the extent of genetic diversity. Seed proteins were analyzed by SDS-PAGE. High genetic variance was observed for days to flowering, days to maturity, number of branches/plant, number of pods/plant, biomass/plant, grain yield/plant and harvest index, whereas low genetic variance was observed for pod length, seeds/pod and 100-seed weight in both years studied. SDS-PAGE of seed proteins showed low inter-accession diversity and no clear differentiation on the basis of origin or source. The genotypes in one cluster with similar agronomic characters did not necessarily belong to the same origin or source. The lack of a geographic pattern of germplasm collected from Pakistan was probably due to exchange of germplasm between neighbouring regions, or because germplasm represented progenies of the same ancestors. Clustering of advanced breeding lines along with an approved variety in one group revealed that only a portion of the genetic diversity has been exploited for improvement of black gram. It is suggested that the genetic base of cultivated black gram should be broadened by involving diverse parents in the breeding programme. Expansion of the genetic base for black gram breeding might be accomplished by systematic use of germplasm that differs in protein profiles and has better quantitative traits. Key words: Black gram, Vigna mungo (L.) Hepper, cluster analysis, gel electrophoresis, genetic diversity, SDS-PAGE. INTRODUCTION Knowledge of genetic diversity is a useful tool in gene- bank management and in planning experiments, as it facilitates efficient sampling and utilization of germ- plasm by identifying and/or eliminating duplicates in the gene stock, and helps in the establishment of core collections. One practical application of knowledge of genetic diversity is in the design of populations for genome mapping experiments (Kaga et al., 1996). Characterization of germplasm using biochemical tech- niques (fingerprinting) has received attention because of the increased recognition of germplasm resources in crop improvement and in selection of desirable geno- types to be used in breeding programmes. Genetic markers are useful for screening germplasm with the minimum cost in time and labour (Nakajima, 1994). Seed protein patterns obtained by electrophoresis have been successfully used to resolve the taxonomic and evolutionary relationships among crops and their wild relatives (Rao et al., 1992; Das and Mukarjee, 1995). They can also be used for distinguishing cultivars of particular crop species (Jha and Ohri, 1996). However, a few studies indicated that cultivars could not be identified by the SDS-PAGE method, as the electro- phoretic patterns of proteins were similar between cultivars (Ahmad and Slinkard, 1992; de Vries, 1996). Among the biochemical techniques, sodium dode- cyl sulphate polyacrylamide gel electrophoresis (SDS- PAGE) is widely used due to its simplicity and effectiveness for describing the genetic structure of crop germplasm. Seed storage proteins have been used as genetic markers in four major areas: (1) analysis of genetic diversity within and between accessions, (2) plant domestication in relation to genetic resource con- servation and breeding, (3) establishing genome rela- tionships, and (4) as a tool in crop improvement. SDS-PAGE is considered to be a practical and reliable method because seed storage proteins are largely inde- pendent of environmental fluctuations (Gepts, 1989, 1990; Murphy et al., 1990; Javaid et al., 2004; Iqbal et al., 2005). Researchers can use information on genetic simi- larity to make decisions regarding selection of superior genotypes for improvement or for use as parents for the development of future cultivars through hybridization. This type of study has not yet been carried out for black gram Vigna mungo (L.) Hepper, although it is an PL ISSN 0001-5296 © Polish Academy of Sciences, Cracow 2005