General and specific combining ability for forage yield in lucerne (Medicago sativa)

Abstract

The genetic control of forage yields was investigated by a combining ability analysis based on a diallel cross made up of the hybrids between nine genotypes of lucerne.

Summer forage yield was found to be controlled by additive and non-additive genes, and winter yield mainly by additive genes. General combining abilities differed markedly between genotypes for both summer and winter yields, and the correlation coefficient between summer and winter yields was high (0.89).

Selected F₂ and F₃ progenies from crosses between Du Puits, Hairy Peruvian, and African cultivars substantially exceeded parental values for summer, winter, and spring forage production under row-sward conditions.

There were positive correlations between summer, winter, and spring productivity in one of the two F₂ experiments and in spaced F₃ plants. Heritability estiniates for summer and winter yield ranged from 22 to 28%, and for spring yield, from 14 to 18%.

On the basis of the estimated genetic parameters, yield increases should be obtained by either family selection or heterosis breeding.