SELECTION OF STABLE VARIETIES BY MINIMIZING THE PROBABILITY OF DISASTER

Many plant breeders use estimates of stability parameters to aid them with making selections in the presence of cultivar X environment interaction. To make selections, the breeder must weight the importance of yield to stability. On the assumption that the plant breeder prefers varieties which minimize the probability of disastrously low yields, a general selection index is proposed which explicitly shows how the plant breeder weighs the importance of mean yield to stability. This index was applied to six international maize (Zea mays L.) yield trials using various stability models. Results indicated that the choice of a stability model can have a substantial effect on the desirability of a variety, and that inclusion of a measure of stability in the index may significantly alter the ranking of varieties compared with considering only the mean yield. The proposed index approach can be a practical way of making selections in the presence of cultivar X environment interaction when stability is a major concern.