The inheritance of curding periods in early summer and autumn cauliflower

Abstract

Two series of diallel crosses were made between (a) eight varieties of autumn cauliflowers and (b) six inbred lines from a single variety of early summer cauliflowers in order to study the inheritance of curding periods. F1's and parents from each diallel were grown in separate randomised block experiments and the analyses presented as conventional Wr Vr graphs. The array points from the diallel analysis of autumn cauliflowers were spread along a regression line of unit slope thus indicating that the gene system controlling curding periods was additive with no evidence of gene interaction in these crosses. Varieties of early/mid period maturity with the exception of Veitch's Autumn Giant possessed most dominant polygenes while late maturity was controlled by recessive polygenes. The diallel analysis of curding periods for the early summer cauliflower inbreds indicated the presence of some interaction which was due to the influence of two lines. On reanalysis without these lines the regression of Wr Vr agreed with a slope of 1, although there was a higher degree of dominance than was shown by the autumn cauliflowers. Analysis of the early summer cauliflower lines for numbers of leaves produced before curding indicated an association between low leaf numbers and early curding, and between high leaf numbers and late curding. None of the F1 hybrids in either series of crosses curded earlier than the earlier curding parent.