BREEDING FOR CREEPING ROOT IN ALFALFA (MEDICAGO MEDIA PERS.)

Abstract

An alfalfa population, consisting of progenies from crosses among 54 plants which had been selected out of a large population of Medicago falcata L. x Medicago media Pers. origin, was scored for degree of creeping-root development. These scores were statistically analysed on the basis of full-sib and half-sib groups. The estimate of Cov(FS) — Cov(HS) was 0.062, and Cov(HS) was 0.091. Therefore, it was concluded that genotypic variation was predominantly additive.Mass selection alone is predicted to be more efficient in breeding for the creeping-rooted character in alfalfa than a combination of mass selection and progeny testing. However, since other characters will usually be selected for along with the creeping-rooted character, the progeny test may have to be used. If progeny testing is used, the optimum number of progeny per parent under test should be approximately 30, provided these have been obtained from at least 8 to 10 different, unrelated, and randomly-selected mates.