Genetic Variability of Mg, Ca, and K in Crested Wheatgrass

Mayland, H. F.; Asay, K. H.

doi:10.2307/3899305

Cited by 20 publications

(22 citation statements)

References 12 publications

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“…The magnitude of K / (Ca+Mg) ratios suggests, however, that the potential for grass tetany increases during the week from the pre-boot to the boot stage in this population of Russian wildrye. This is in accordance with previous findings in crested wheatgrass (Mayland and Asay 1989. ans. 3 Hb = heritability in the broad sense on a mean basis.…”

Section: Resultssupporting

confidence: 94%

“…When Mg, K, and Ca were all included in the regression analysis, 95% of the variation was accounted for. This confirms that selection based on RTP places more emphasis on Mg than on Ca and K, as was initially reported by Mayland and Asay (1989).…”

Section: Resultssupporting

confidence: 88%

“…This index, which provides an estimate of the grass tetany producing potential of an individual progeny line, comprises information involving the interactions of Mg, Ca, and K (Mayland and Asay 1989, Mayland and Grunes 1979, Kemp and t'Hart 1957. The index gives additional weight to the Mg concentration in the forage and should be particularly useful in evaluating the progress in breeding programs to reduce the grass tetany hazard.…”

Section: Resultsmentioning

confidence: 99%

“…A reduced tetany potential index (RTP) was computed according to Mayland and Asay (1989) as follows:…”

Section: Methodsmentioning

confidence: 99%

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Genetic Variability for Elements Associated with Grass Tetany in Russian Wildrye

Asay¹,

Mayland²

1990

Journal of Range Management

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Grass tetany (hypomagnesemia) may be an important factor limiting productivity of animals grazing Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski]. This malady is associated with relatively low concentrations in the forage of Mg and Ca, and high values for K and K/(Ca+Mg). We studied the genetic variablity in a Russian wildrye breeding population for mineral elements that relate to grass tetany in ruminants. Forty-five progeny lines, established as spaced plants in a randomized complete block, were sampled at the pre-boot and boot stages in each of 2 years and analyzed for Mg, Ca, K, and P. Although seasonal variation was evident, K/(Ca+Mg) of the progeny lines ranged from 3.2 to 4.6, well above the 2.2 level at which a 5% incidence of grass tetany has been found in dairy cattle. With few exceptions, progenies differed for all traits evaluated. Differences among progenies were relatively consistent over harvests for all traits. A reduced tetany potential (RTP) was computed as the sum of normalized Mg and reciprocal of K/(Ca+Mg) values, providing an estimate of the grass tetany risk for individual progeny lines. The variation among progenies, and the magnitude of broad-sense heritability estimates for RTP (0.48) and K/(Ca+Mg) values (0.31), indicate that mineral ion composition of this breeding population can be altered through breeding. The high K/(Ca+Mg) values in the population suggest that it may be helpful to introduce genetic factors conditioning lower grass tetany potential from other sources. Intercharacter correlations suggest that breeding for higher levels of Mg will be accompanied by increased Ca and, to a lesser extent, increased K.

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Section: Resultssupporting

confidence: 94%

Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 99%

“…A reduced tetany potential index (RTP) was computed according to Mayland and Asay (1989) as follows:…”

Section: Methodsmentioning

confidence: 99%

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Genetic Variability for Elements Associated with Grass Tetany in Russian Wildrye

Asay¹,

Mayland²

1990

Journal of Range Management

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“…The most effective method is to provide sufficient Mg in the herbage to meet the animal requirement (Wilkinson et al, 1987). Recent research suggests that development of grasses with more favorable K/(Ca+Mg) is feasible (Mayland and Asay, 1989;Asay and Mayland, 1990;Mayland and Sleper, 1993;Moseley and Baker, 1991;Vogel et al, 1989). Increasing the dietary Mg intake in brood cows not only reduces the risk of grass tetany, but may also benefit the overall performance of the animal (Stuedemann et al, 1983).…”

Section: Introductionmentioning

confidence: 99%

Yield and mineral concentration of HiMag compared to other tall fescue cultivars grown in the southern piedmont

Wilkinson¹,

Mayland

1997

Journal of Plant Nutrition

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Revisiting variation in leaf magnesium concentrations in forage grasses for improved animal health

et al. 2020

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Aims An Italian ryegrass cultivar (Lolium multiflorum Lam. cv. Bb2067), selected and bred for increased leaf magnesium (Mg) concentration in the 1970s, reduced the incidence of hypomagnesaemia in sheep under experimental grazings. Here, we report evidence from archival experiments showing that cv. Bb2067 had consistently greater Mg concentrations at multiple sites. We also aimed to quantify variation in leaf Mg concentration among modern perennial ryegrass (Lolium perenne L.), hybrid ryegrass (Lolium perenne × multiflorum), and tall fescue (Festuca arundinacea Shreb.) cultivars. Methods Data are reported from unpublished 1980s fieldplot experiments for cv. Bb2067 and contemporaneous reference cultivars, sown at two UK locations in 1983 and 1984, and from 397 cultivars of modern forage grass in 13 UK-based breeding experiments sampled in spring 2013. Results Across sites, years and cuts, cv. Bb2067 had a consistently greater leaf Mg concentration and lower potassium (K) concentration and forage tetany index (FTI) than reference cultivars in the 1980s experiments. Seasonal variation in leaf Mg and K concentrations and FTI were observed in the 1980s experiments, with K concentrations being generally greatest and Mg concentrations smallest in spring. Among modern forage grasses, there was large variation in leaf Mg concentration (up to 6.3-fold) and FTI (up to 2.1-fold), both within and between species, which varied independently of yield. Among a subset of hybrid ryegrass cultivars, there is evidence that the high Mg trait is already present in some modern breeding lines, albeit previously unreported. Conclusions The variation in leaf Mg concentration and FTI among old and new cultivars shows there is considerable potential to breed forages with improved mineral quality to improve livestock health, potentially without compromising yield or other nutritional traits.

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Genetic Variability of Mg, Ca, and K in Crested Wheatgrass

Cited by 20 publications

References 12 publications

Genetic Variability for Elements Associated with Grass Tetany in Russian Wildrye

Genetic Variability for Elements Associated with Grass Tetany in Russian Wildrye

Yield and mineral concentration of HiMag compared to other tall fescue cultivars grown in the southern piedmont

Revisiting variation in leaf magnesium concentrations in forage grasses for improved animal health

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