Annual Ryegrass Seed Yield Response to Grazing during Early Stem Elongation

Abstract

Spring grazing annual ryegrass (Lolium multiflorum Lam.) seed fields with sheep (Ovis aries) is a common practice. The effects of grazing duration in early stages of stem elongation on seed yield and its components are not well known. We studied four durations of spring grazing annual ryegrass with sheep over a 2‐yr period on an Argiaquic Xeric Argialboll soil. Grazing was begun before onset of stem elongation. Treatments were no grazing (G0) and grazing until one‐third (G1), two‐thirds (G2), or all (G3) primary tillers had their apical meristems removed. Leaf area was progressively reduced by grazing duration. The number of fertile tillers increased with grazing duration in the first year, but the effect was not significant in the second year. Grazing did not affect the number of spikelets per spike or florets per spikelet in the first year. In the second year, G2 and G3 reduced spikelets per spike and had no effect on the number of florets per spikelet, whereas G1 did not affect either character. Both G2 and G3 decreased seed weight in the first year, while G1 had no effect; treatments did not affect seed weight in the second year. Grazing treatment did not affect total herbage dry matter at seed maturity, seed yield, or seed quality in either year. We conclude that, in western Oregon, grazing annual ryegrass in late winter and early spring up to the time when the apical meristem of all primary tillers are removed (G3) does not reduce seed yield. Grazing until about one‐third of primary tillers lose their apical meristem (G1) may actually improve seed yield.

Grazing Termination Date Influence on Annual Ryegrass Seed Production and Reseeding in the Southeastern USA

“…Lower seed yields for Rio and Surrey is partially due to lower spike density (Table 2). These results coincide with results reported by Young et al (1996) and Brown (1980) In 1997, GTD did not influence seed yield of Beefbuilder, Gulf, and Jackson. Lower seed yields of the other cultivars were probably due to seed shattering since there was no difference in spike density between the 31 March and 14 April GTDs except for Surrey.…”

Efeito da irrigação, épocas de corte da forragem e doses de nitrogênio sobre o rendimento de sementes de milheto

“…A identificação da intensidade da remoção da forragem e a época de diferimento do pastejo foram estudadas durante dois anos por Young et al (1996). Neste trabalho, os rendimentos de sementes de azevém anual nas três intensidades de utilização (um terço, dois terços e todos os perfilhos primários em elongação visível ou palpável removidos) não diferiram dos rendimentos obtidos do tratamento sem pastejo.…”

Seed variation among annual ryegrass cultivars in south‐eastern USA and the relationship with seedling vigour and forage production

“…(1975) for naturalized and two commercial seed populations of diploid annual ryegrass, ranged from 2·0 to 2·4 mg per seed. For Gulf annual ryegrass, Young et al . (1996) reported a range of single‐seed weights, as affected by a sheep grazing treatment, from 2·3 to 2·6 mg.…”

“…Effects of environmental conditions on growth and production of seed are also factors in seed size that can result in within and among cultivar variation. Young et al . (1996) reported significant differences in the seed weight of the ‘Gulf’ cultivar of annual ryegrass under different grazing treatments in 1978, but not in 1979.…”