VARIATION OF CHEMICAL CONSTITUENTS AND MORPHOLOGICAL CHARACTERS WITHIN AND BETWEEN ALFALFA POPULATIONS

Abstract

A total of 326 alfalfa plants, classified into five populations, were grown in three replicates in the greenhouse and studied for variability for the following characters: leaf size, internode between branches, interval between flowering, dry matter of leaves and stems at two cuttings, percent leaf at two cuttings, in vitro digestibility, and contents of crude fiber, ether extract, nitrogen, phosphorus, sulfur, potassium, magnesium, and calcium in leaves and stems. The variance analysis showed that there were significant differences between plants for all characters except in vitro digestibility in leaves and ether extract in stems. Components of variance for some characters were nearly as great between populations as within, while for others they were mainly due to within-population variation. The greatest differences occurred between populations classified as M. falcata and M. sativa. The M. media populations resembled the M. sativa population to a greater extent than the M. falcata type. Frequency distribution graphs indicated that the range for the various characters differed considerably, and genotypic differences between plants were indicated for practically all of them. Correlation coefficients between characters, although often significant, generally were of rather small magnitude. However, certain relationships may be useful in a breeding program.