Breeding for Mg, Ca, K, and P Content in Tall Fescue1

Abstract

Diseases such as hypomagnesaemia (grass tetany) have been associated with deficiencies of certain minerals in tall fescue (Festuca arundinacea Schreb.) and in other forage species. To overcome these deficiencies through breeding, information is needed on the inheritance of accumulation of these minerals. Objectives of our investigation were to measure the heritability of the accumulation of Mg, Ca, K, P, and a ratio, K/(Ca+Mg), and their interrelationships in tall fescue. Two diallel mating sets, each with six parents, were randomized and planted in one experiment. Forage was analyzed for Mg, Ca, K, P, and K/(Ca+Mg) for three harvest dates in 1974 and in 1975. Parents and progenies differed significantly for all minerals studied except that progenies were not significantly different for K in one of the diallel sets for the first harvest date. Estimates of general combining ability were more important than estimates of specific combining ability in the inherited uptake of these minerals. Heritability values calculated by the progeny‐parent regression and standard unit method indicated that progress can be made in breeding for higher mineral levels of most minerals at most harvest dates. Since the K/(Ca+Mg) ratio was highly heritable, progress in breeding a tall fescue with low hypomagnesaemia potential should be possible. Correlation of Mg between years was highly significant in one diallel but not in the other. Correlation of K/(Ca+Mg) between years was highly significant at all sampling dates for both diallels. Correlations coefficients between years for Ca, K, and P were more erratic.