Genetic Variation for Selenium Content in Tall Fescue

Abstract

Selenium is an element necessary for good animal health. No information is available on inheritance of Se concentration in tall fescue (Festuca arundinacea Shreb.). Therefore, the purpose of this investigation was to determine the nature of genetic variation of Se concentration in tall fescue. To accomplish this objective, 15 parental clones were randomly chosen from a broad-based population, and their half-sib (HS) progenies were generated using a polycross mating design. Selenium analysis was determined flourometrically by digesting dried, ground herbage samples in 3:1 HNO3/HCIO4. Significant genetic variation was observed among HS families in the fall for Se concentration. Heritability, calculated using parent-offspring (PO) regression, gave estimates of 18% for summer and 68% for the fall. Heritability and genetic gain estimates were maximized in the fall, as compared with the summer, largely because of a large environmental component. Genetic gain, expressed as a percentage of the mean of parents, predicted an advance of 1 9 % for fall herbage. Progress in selecting for improved concentrations of Se in the fall in this population of tall fescue is likely.INHERITANCE of mineral concentrations in cool-sea-1 son forage grasses has largely concentrated on the elements Mg, Ca, and K (Sleper et al., 1989). These three elements have received attention by forage grass breeders because of their importance in grass tetany or hypomagnesemia. Grass tetany of ruminants is associated with low blood-serum Mg levels (Kemp,

Inheritance Characteristics of Brown Patch Resistance in Tall Fescue

“…would be difficult based on a narrowsense heritability estimate of 0.41 and 0.28. McQuinn et al (1991) reported that the narrow-sense heritability of 0.68 for selenium content in tall fescue would allow for the use of phenotypic recurrent selection or simple mass selection. reported that predicted gains from phenotypic selection of 58, 21, and 48% were high enough to continue with a phenotypic selection program for improving digestibility in tall fescue.…”

“…In an openpollinated species, polycross mating can be implemented to develop half-sib progenies that can be studied to determine the genetic variances, general combining ability (GCA), heritability, and gain from selection (Nguyen and Sleper, 1983a). In tall fescue, polycross progeny tests have been effectively used to estimate the genetic parameters of several quantitative traits and have been preferred over the diallel design McQuinn et al, 1991;Nguyen and Sleper, 1983a). In developing synthetic cultivars information on the GCA of individuals is vital in determining which plants should be inter-pollinated, as this is measurement of the additive gene action.…”

Absorption of Excess Selenium and Sulfur by Plants and Animals

“…uptake and concentration in the forage (Westermann and Robbins 1974). McQuinn et al (1991) Rosenfeld and Beath (1964) identified three plant groups based on their ability to accumulate Se when growing on Se-rich soils. The first two groups of plants were identified by their potential to accumulate moderate or very high concentrations of Se.…”

Tall fescue in Australia and New Zealand

“…Nguyen & Sleper (1981) found significant additive genetic variance for mineral levels but found that the narrow sense heritability of the ratio was lower than those of the elements individually. Thomson et al (1988) suggested sodium levels as a limiting factor in tall fescue quality, and McQuinn et al (1991) showed significant variation in selenium levels.…”