RELATIONSHIPS BETWEEN SEEDLING TRAITS AND MATURE PLANT YIELD IN ALFALFA

Abstract

To compare some seedling traits with the yield of alfalfa plants when grown as a crop stand, 1000 individually weighed seeds of Beaver alfalfa (Medicago sativa L.) were germinated in a growth chamber in a greenhouse mix containing soil. The dates of emergence and expansion of the first trifoliolate leaf, the weight of the first trifoliolate leaf, and the height, shoot number, leaf number and yield 10 wk after seeding were all correlated with each other. The seedlings were transplanted in late summer in to a 15 × 15-cm grid in the field, simulating a crop stand. Individual plant yields were determined in each of the two succeeding years. The number of shoots present at the first harvest was determined in the seedling year. There was no difference in the mean weight of seeds which emerged and those which did not. The mature plant traits were all strongly correlated with each other (P > 0.001). Although the seed weight and seedling traits had low correlations with mature plant traits (r < 0.25), the top 10% of seedlings on the basis of the date of first trifoliolate leaf expansion or seedling yield exceeded the population (averaged over the two years) by more than 31 and 41% respectively.Key words: Alfalfa, Medicago, seedling, selection, yield