GENETIC VARIABILITY AMONG LIMA BEAN (PHASEOLUS LUNATUS L.) LANDRACES COLLECT IN PIAUI STATE

摘要

The lima bean (Phaseolus lunatus L.) is one of the main legumes cultivated in tropical countries, performing better in the humid tropics and warm (RACHIE et al., 1980). According to Rodrigues et. al. (2002) there is a high genetic diversity in genus Phaseolus, and this can be used in breeding programs. The most important step in a breeding program is the choice of parents with good performance and wide genetic base. Genetic diversity is one of the criteria of parent selection in the hybridization program. Thus measures of the genetic divergence may help breeders to concentrate their efforts only on the most promising combinations. The availability of transgressive segregant in any breeding program depends upon the diversity between the parents involves. The divergence analysis has a definite role to play in an efficient choice of divergent parents for hybridization to exploit maximum heterosis. Some studies have permitted to establish genetic relationships among cultivars and landraces from different origins and also to link the diversity observed in different geographic regions and other elements of the physical environment. The aim of this work was to estimate the genetic divergence of 70 landraces of lima bean in Piaui State and correlation between genetic distance and geographical distance.