GEOGRAPHIC AND GENETIC VARIATION OF GROWTH AND BIOMASS PRODUCTION IN COCOITE (Gliricidia sepium) UNDER TWO SOIL MOISTURE CONDITIONS

Abstract

An open-pollinated provenance-progeny test was established under two soil moisture conditions, in order to evaluate the variation in plant height and biomass production among and within nine populations of Gliricidia sepium (Jacquin) Kunth ex Walpers (cocoíte), as well as to identify the effects of water deficit on the structure of the phenotypic variation. Variation in height and biomass production was significant (p£0.05) among and within populations, even though their joint contribution to total phenotypic variation was less than 10 %. Interaction of moisture levels with populations and with families within populations accounted for an additional 10 and 3 % of total variation, respectively. Water deficit reduced height growth and biomass production of plants and modified the variance structure. Thus, under favorable moisture conditions, provenance variation contributed with 11 % of total variation, and families within populations added 4 %; however, under restricted moisture conditions, provenance variation was strongly reduced while the family-within-population variation was increased.