HERITABILITY AND GENETIC CORRELATION OF SOLUBLE SOLIDS, BULB SIZE AND SHAPE IN WHITE SWEET SPANISH ONION

Abstract

Heritability of size, shape and soluble solids content of bulbs in a White Sweet Spanish onion cultivar (Allium cepa L.) was estimated in two ways: (1) by calculating regressions of half-sib offspring on female parent, and (2) by calculating half-sib family intra-class correlations. Heritabilities of bulb weight and diameter were low (0 and 28%; 0 and 27%); bulb height, intermediate (45 and 48%); shape index and solids, high (89 and 62%; 79 and 82%). Phenotypic correlations among five variables were separated into additive genetic and environmental correlations. The data contain negative genetic correlations between solids and bulb size; if confirmed, such a relationship would be of concern to plant breeders when selecting onions for higher solids content.