Comparative analysis of seed morphometric and allozyme data among four populations of neem (Azadirachta indica)

The objectives of this study were to determine the patterns of variability and to compare genetic distance between seed morphometric and allozyme data of neem (Azadirachta indica). Phenotypic variation from open pollinated seed materials at 12 isozyme loci was examined using starch gel electrophoresis for four populations from Thailand, Bangladesh and Kenya. All four populations exhibited high levels of variation for seed parameters and isozymes. UPGMA cluster analysis of Nei's genetic distance when based on isozymes revealed two genetic groups. The population from Kenya showed a close genetic relationship with the Bangladeshi populations. The population from Thailand exhibited a distant relationship with the other three populations. This result suggests that the Kenyan population was introduced from the Indian subcontinent. In contrast, cluster analysis of seed morphometric data indicated three different groups of populations. The population from Kenya showed a distant relationship with all other populations. The study demonstrates that allozyme data may not correspond with morphometric traits when measuring genetic distance. It is suggested that this controversy may depend on environmental influence on morphometric traits, possibly also on the enzyme patterns.