EVALUATION OF PROVENANCE VARIATION ON EARLY GROWTH AND SURVIVAL OF NEEM (<em>AZADIRACHTA</em> <em>INDICA</em>) IN BANGLADESH AND INDIA

Abstract

Twenty provenances of neem (Azadirachta indica A.Juss.) were studied at three sites of the international provenance trials in Bangladesh and India after a growing period of about seven months in the field. Significant differences were observed between provenances in height and collar diameter. Mean plant heights, collar diameters and survival rates were 52.56 cm, 8.13 mm and 68.53% at site I; 42.19 cm, 6.72 mm and 89.02% at site II; and 36.07 cm, 4.78 mm and 45.50% at site III respectively. Variations in collar diameters and survival rates were detected at sites I and II and were associated with latitudinal clines. Positive correlations between heights and survival rates and between collar diameters and survival rates were detected at all three sites. Regression analyses indicated significant amounts of variation for collar diameter at sites I and II due to the effect of latitude. The data on height, collar diameter and survival rate of trees at the individual sites were subjected to principal component analysis (PCA). The first principal component accounted for 83% (site I), 86% (site II) and 72% (site III) of variation. The second principal component accounted for 16% (site I), 12% (site II) and 28% (site III) of
variation. PCA revealed distinct population differentiation associated with variations in height and survival rate of neem populations at the three sites. Ecoclimatic attributes played an important role in the differentiation of neem populations and thereby affected their growth and survival during the early stages of establishment.