Novel Variation in Tomato Species Hybrids

Abstract

Novel variants have appeared in F2 of L. esculentum and the self-incompat. spp. L. peruvianum and L. chilense. Their phenotypes are drastically different from the rest of the F2 and from the parental spp. Where tested, the condition is caused by one or more recessive genes. A single recessive gene og is responsible for the old gold variant in the progeny of a hybrid of L. esculentum x L. chilense. The chilense parent plant is +/og. Phenotypic expression of og within L. chilense seems to be equal to that in the hybrids. Information concerning the origin of the other variants is not so conclusive, yet the available facts are in keeping with an explanation like that for og[long dash]namely, fixation, on selfing the F1, of recessive genes present in heterozygous form in the self-incompat. parental sp. Inbreeding L. peruvianum and L. chilense has yielded other recessive genes of major effect. For reasons presented, hypotheses based on high mutation rates induced by hybridity and on complementary interaction of normal alleles of the parents provide less likely explanations.