Studies of intervarietal hybridization in subterranean clover (Trifolium subterraneum L.).

Abstract

Subterranean clover pollen germinates freely on an agar medium at relative humidities above 95 per cent. and at temperatures between 20 and 25°C. Temperature was not as critical as relative humidity, since pollen germinated freely a t 4°C. Based on these findings an improved technique for the artificial hybridization of subterranean clover varieties was developed. With this technique 35.3 per cent. of the emasculated and cross-pollinated florets set seed in 18 different intervarietal crosses. Varying degrees of compatibility exist between different varieties. The percentage of emasculated florets in Tallarook which set seed from pollinations with different male parents varied from 75 per cent. for Dwalganup to 6.5 per cent. for Wenigup. The characteristics of a number of the F1 hybrids are described. The extent to which different parental characters were dominant in the hybrids is indicated.