Effect of number of parents on some important biometric genetic parameters in rapeseed (Brassica napus L.)

Half F₂ diallel crosses of eight spring cultivars of rapeseed were used in partial circulant diallel analyses to estimate biometric genetic parameters for phenological traits, yield components and seed yield. The greatest variation in the GCA-to-SCA mean square ratio was related to days to flowering, and its lowest variation to days to maturity. A high coefficient of variation of the narrow-sense heritability estimate was obtained for days to maturity, followed by plant height and seed yield. For diallel analysis with a low number of parents, the differences of the heritability estimates of the traits were small; therefore, for precise estimation of heritability, a high number of diallel crosses will be preferred.