Response to mass selection and estimation of heritability for oil content in Dimorphotheca pluvialis

Abstract

Three populations of Dimorphotheca pluvialis (L.) Moench were subjected to mass selection for increased oil content. After three cycles of selection, at a selection intensity of 10%, in all three populations a significant increase in oil content was observed. The average gain in oil content per selection cycle varied from 0.5% to 1.2%. Realised heritabilities ranged from 0.15 to 0.58. It is likely that the observed differences in response and heritability for oil content can be attributed to different genetic constitutions of the populations used. Though heritabilities are specific for populations, selection procedures and environmental circumstances, the observed values for the realised heritabilities indicate that a substantial part of the phenotypic variance is additive genetic variance. Therefore, continued (mass) selection for increased oil content will be effective in Dimorphotheca.