METHODS OF PREDICTING GENOTYPE VALUE AND HETEROSIS FOR OFFSPRING OF HYBRIDS
Zhu Jun (Agronomy Department, Zhejiang Agricultural University, Hangzhou 310029)
By parents and F_1 hybrids of crops, methods of predicting genotype value and heterosis are proposed for offspring of hybrids. The MINQUE (1) procedures can be used for estimating variance components and for predicting genetic effects by analyzing diallel crosses with an additivedominance model. Predicted additive and dominance effects can be further used in predicting genotype values for different generations of F_1, F_2, BC_1 and BC_2. By predicted heterosis over mid-parent value or over better-parent based on population mean, heterosis for other generations can be obtained. A simple formula is proposed for predicting the number of generations of a cross which still has heterosis over better-parent. The number of generations is a function of heterosis over mid-parent value based on population mean and genetic difference between two parents. A worked example of six-parent diallel analysis in cotton is given for predicting F_2 genotype value, heterosis and the number of generations for each cross.