Submitted to: Grassland International Congress
Publication Type: Proceedings
Publication Acceptance Date: 2/3/2005
Publication Date: 7/4/2005
Citation: Larson, S.R., Mayland, H.F. 2005. Qtl analysis of mineral content and grass tetany potential in leymus wildryes. Grassland International Congress. Interpretive Summary:
Technical Abstract: Grass tetany is a metabolic ailment in ruminants, occuring when animals graze rapidly growing C3 grasses with a K / (Mg + Ca) ration (KRAT) greater than 2.2, based on equivalent cation units. High KRAT values have been documented in several forage species including Russian wildrye (Psathrostachys juncea). The objective of this experiment was to identify quantitative trait loci (QTLs) controlling mineral content and grass tetany potential in a related genus, using full-sib interspecific mapping populations derived from a cross of Great Basin wildrye (Leymus cinereus) and creeping wildrye (L. triticoides). Significant QTL effects for all three minerals (i.e. K, Ca, and Mg) contributing to grass tetany potential were identified, including a major QTL effect for %Ca and KRAT on chromosome LG3b in both populations. Interestingly, this chromosome region and homoeologous regions of LG3a also have major effects on rhizome proliferation. Like Russion wildrye, L. cinereus is a tall caespitose grass with relatively high grass tetany potential whereas L. triticoides is a strongly rhizomatous grass with relatively lower grass tetany potential. These results contribute to our understanding of the genetic basis of mineral content and tetany potential in grasses. These evaluations identifed plant materials and molecular markers that will be used in forage grass improvement.