Variation and heritability of seed mass in chia (Salvia hispanica L.)

Variation and heritability of seed mass in the Mesoamerican crop chia, Salvia hispanica L. was studied to examine the feasibility of selection for the trait. Genotypic variation in seed mass in wild/ cultivated and domesticated accessions of chia from different origins was assessed. Broadsense heritability of seed mass was estimated using variances associated with parental and F-2 generations derived from two crosses and from the response to one cycle of selection. Significant ( P <= 0.0001) genotypic variation was observed among accessions. Mean seed mass for domesticated accessions (14.84 mg/100 seeds) was greater than that of the wild accessions (11.29 mg/100 seeds) by 31%. The heritability of seed mass was relatively high in chia (0.75), suggesting that this trait is under strong genetic control. This conclusion was supported by a single selection cycle from the F-2 to F-3 generation that produced a 16% increase in mean seed mass. The realized heritability estimated based on this one cycle of selection also was 0.75. These observations indicate that gains from selection in chia seed mass are possible when mass selection is conducted in early generations. Basic information is thus provided for future breeding efforts in a species for which little or no knowledge of inheritance currently exists.