Genetic Variability and Heritability of Certain Forage Quality and Mineral Constituents in Lolium‐Festuca Hybrid Derivatives¹

Abstract

Breeding tall fescue (Festuca arundinacea Schreb.) cultivars with high digestibility and high nonstructural carbohydrate content and the proper balance of potassium (K), calcium (Ca), and magnesium (Mg) may overcome many of the seasonal problems of cattle grazing the species. The objective of this paper is to present estimates of genetic variability and heritability of digestibility, water‐soluble carbohydrates, K, Ca, Mg, and the K/(Ca + Mg) ratio and their association in selected Lolium‐Festuca hybrid derivatives. Twenty‐eight parental clones were evaluated in a spaced plant nursery, and their polycross progenies (pep) in seeded rows in Madison County, Kentucky. Additionally, the pcp were evaluated in sod plots in Fayette County, Kentucky. A combined analysis of variance of parents and pep at both locations for forage quality and mineral constituents showed highly significant differences for these characteristics among selections, generations, years, and their interactions. Broad sense heritahility estimates among parental clones were high for all constituents, indicating that a considerable portion of the total variability was genetic. Heritability estimates obtained from regression of pcp on parents were relatively high when parents and pcp were grown in close proximity for all constituents except K and the K/(Ca Mg) ratio. When parents and pcp were grown in widely different environments, the heritability estimates were low for all constituents. Thus, breeding materials should be evaluated for forage quality and mineral constituents in a minimum of two locations with widely different environments. Predictions of response to selection were disappointingly small for all characters. The data suggest that progress in breeding for low tetany potential in these materials, while possible, may require considerable time and effort.

Environmental and Genetic Variation for Water Soluble Carbohydrate Content in Cool Season Forage Grasses

“…He also found relative WSC contents in parents and hybrids were consistent over generations under both spaced plants and sward conditions. In contrast, Buckner et al (1981), using a polycross progeny test in Lolium-festuca hybrid derivatives, reported when parent and HS families were evaluated in the same environment h 2 op were much higher than when they were grown in different environments. They suggested that a minimum of two locations with widely different environments was necessary to develop varieties for forage quality.…”

“…Cooper (1962), in cocksfoot, estimated relatively high h 2 op which ranged from 0.78 to 0.56 for July and August cuts, respectively. Buckner et al (1981), using a polycross progeny test in Lolium-festuca hybrid derivatives, estimated h 2 b of 0.55 and h 2 op of 0.01 to 0.47 for WSC. Burner et al (1983) analyzed variance of tall fescue and obtained h 2 b =0.55.…”

Genetic Variation for Selenium Content in Tall Fescue

“…An underlying assumption of PO regression is that all genotype X environment interactions between parents and progenies are zero (Hanson, 1963;Dudley and Moll, 1969;Vogel et al, 1980;Casler, 1982). A way to remove this potential bias is to regress progeny means on parental means evaluated under different environments (Buckner et al, 1981). In this investigation, only one location was used, but data were collected over a 2-yr period; however, it must be realized that data collected from one location may bias heritability estimates upward (Nguyen and Sleper, 1983a).…”

Response to Selection for Reduced Grass Tetany Potential in Crested Wheatgrass

“…; Hides and Thomas, 1981); Lolium-Festuca hybrids (Buckner et al, 1981); reed canarygrass (Phalaris arundinacea L.; Hovin et al, 1978); orchardgrass (Daclylis glomerata L.; Mika et al, 1988;Stratton and Sleper, 1979); crested wheatgrass (Mayland and Asay, 1989); tall fescue (Festuca arundinacea Schreber; Nguyen and Sleper, 1981); and Russian wildrye [Psathyrostachys juncea (Fischer) Nevski; Asay and Mayland, 1990].…”