Heritability and Interrelationships of Pod Length and Seed Weight in Guar

This study was undertaken to estimate heritability of pod length and seed weight in guar, Cyamopsis tetragonoloba (L.) Taub., and to determine genetic relationships between the two traits. Narrow-sense heritability (h²) estimates ranged from 0.63 to 0.68 for pod length and from 0.54 to 0.57 for seed weight. An additive-dominance model was adequate to explain gene action involved in the inheritance of both traits. Estimates indicate a minimum of 5 loci or chromosome segments control pod length and 2 control seed weight. Phenotypic correlations between pod length and seed weight were highly significant and positive. Genotypic correlations between the two traits were low and positive. Moderate to high heritability values for the two traits indicate that selection for improvement in either trait should be fairly rapid. Low genotypic correlations between the traits should not pose a significant barrier in developing large seed, grain-type cultivars.