Diallel analysis of floral morphology in radish (Raphanus sativus L.)

We made a 5 x 5 diallel set of crosses between five inbred lines, four Japanese and one Chinese, and diallel analyses of radish floral morphology were conducted to estimate the genetic parameters underlying 13 floral traits. The modes of inheritance of 12 traits (but not anther length on the long stamen) followed the additive-dominance model. Broad-sense heritabilities of the 12 traits were 0.93-0.99, suggesting that floral morphology is highly heritable. But narrow-sense heritabilities differed among traits, ranging from 0.34 to 0.89. Pistil and stamen heights, tube length, and stigma position were explained mainly by additive effects, but anther, stigma, petal, and whole flower sizes were affected greatly by dominance effects as well as by additive effects. The correlations between the 13 traits suggested that some floral traits (e.g. stigma size and position) are more or less independent, indicating the possibility of creating lines with new floral morphologies by selecting for these genetically independent traits. A flower with a larger and higher stigma might improve the production of cross-pollinated seeds through enhancement of pollination efficiency. In that case, by selecting for stigma position in an early segregating generation and for stigma size in a later generation, it should be possible to produce new parental lines with effective floral morphology for F ₁ seed production.