DERIVATION OF SUPERIOR F5 LINES FROM HETEROTIC HYBRIDS IN PEA

F-5 seeds from six highly heterotic F-1 hybrids were produced to deter mine whether the superior performance of F-1 hybrids could be fixed in pure-line derivatives of pea (Pisum sativum L.). For each cross, 24-3 1 F-5 lines derived from single seed descent were compared with F-1 hy brids and their parents in two environments. The F1( )hybrids out-yiel ded the best parent by up to 11%. All crosses produced F-5 lines which were as high in yield as the F-1 hybrids indicating that pure-line de rivatives equivalent in yield to the heterotic F-1 hybrid could be dev eloped by conventional breeding. Heterosis of the F-1 hybrids over the best commercial cultivar was thus a useful indicator of the future pe rformance of the pure-line derivatives. These results indicate that ov erdominance was not an important component of heterosis in peas.