Hybrids of Trifolium pratense × Trifolium pallidum1

Abstract
Triploid hybrids, 2n=22, were produced from crosses of autotetraploid Trifolium pratense L., 2n=28, × diploid T. pallidum Waldst. & Kit., 2n=16. We obtained 194 hybrids from 2,575 hand‐pollinated florets. Many hybrids were vigorous, flowered profusely, and were intermediate to the parent Species in morphology. Chromosomal homology of the parental genomes was slight. At metaphase I the hybrids averaged 7.32 I, 6.34 II, 0.54 III and a very low frequency of multivalents containing more than three chromosomes. The hybrids were male‐ and female‐sterile. A hypo‐autotriploid plant of T. pratense>, 2n=20, was fertile and averaged 1.90 I, 2.89 II, and 4.08 III in microsporocytes at metaphase I.