CONTRASTING GENETIC-VARIATION AMONGST LENTIL LANDRACES FROM DIFFERENTGEOGRAPHICAL ORIGINS

Lentil landraces from South Asia exhibit a low diversity and discordan ce with landraces from other countries according to a combination of q ualitative and quantitative agromorphological characters. They exhibit specific phenological adaptation to the South Asian environment which precludes the direct use of alien germplasm in breeding programs in S outh Asia. An understanding of the genetic relationships and diversity of South Asian lentil landraces, in relation to landraces from other countries, is important in attempting to widen the genetic base of ger mplasm in the region. The objectives of this study were to investigate the genetic relationships between lentil landraces from 3 South Asian countries (India, Nepal and Pakistan) and those from 13 other countri es and to determine their relative genetic diversities, using both iso zyme electrophoresis and random amplified polymorphic DNA (RAPD) analy sis. Polymorphisms were observed for 7 isozyme loci (16 alleles) and 2 2 RAPD loci. According to Nei's genetic distance, germplasm from Afgha nistan clustered with that from the South Asian countries. The germpla sm from these countries was striking different to that from the other countries studied. Based on genetic distance estimates from RAPD analy sis, the countries with the lowest diversity were Pakistan, Afghanista n and Nepal. These data support evidence at the morphological level of a genetic bottleneck in lentil landraces from South Asia. Genetic rel ationships between countries outside the South Asian group are discuss ed. Classification into macrosperma and microsperma types did not refl ect overall country relationships.