Variation for reproductive and agronomic traits among T-repens x T-nigrescens third generation backcross hybrids in the field -: Reproductive and agronomic traits among BC3 hybrids of T-repens x T-nigrescens

Interspecific hybridisation with Trifolium nigrescens Viv. is a possible strategy to improve the reproductive potential of white clover (Trifolium repens L.). Following the development of a fertile F1 hybrid, three generations of backcrossing have been carried out using T. repens as the recurrent parent. Vegetative characteristics, stolon growth and seed yield components of the backcross (BC) 2 and 3 generations, as well as the parental species were measured on spaced plants grown in the field. Leaf size and plant spread of the BC2 and BC3 generations were less than T. repens but there was no difference in plant fresh weight. Numbers of inflorescences per plant and florets per inflorescence of the backcrosses were greater than T. repens however this was not reflected in differences in seed yield per plant as T. repens had more seeds per floret and per plant than the backcrosses. Differences in stolon length, the proportion of flowering nodes and the pattern of axillary bud development were observed between T. repens and the backcrosses. Significant variation among the BC 3 generation for vegetative and reproductive traits was observed. Individual plants among the BC 3 generation were identified that combine high forage yield, substantial inflorescence production and good fertility, and these will form the basis of further selection.