Studies of Colchicine-Induced Tetraploids of Trifolium Hybridum L.: I. Cross and Self-Fertility and Cytological Observations1

Tetraploid alsike produced by colchicine treatment from diploid seed was initially high in forage yield but low in fertility By selection of the more fertile plants in successive generations the fertility was raised to the diploid level by the seventh generation Diploid and tetraploid plants were found to be incompatible, which should facilitate isolation and increase of tetraploid strains A fairly high frequency of self-compatibility was noted upon selfing. This character was not retained in the progeny. Cytological studies of fifth generation plants showed a stable condition at meiosis. There was a high frequency of quadrivalents which separated regularly at anaphase. Cytological behaviour was not closely associated with varying fertility The evidence supported the view that fertility is largely genetically controlled