Flowering propensity of two New Zealand perennial ryegrass cultivars originating from different ecotypes

Abstract

Tiller turnover at flowering is an integral component of the perennation strategy in many temperate grasses. While vernalisation and daylength requirements for flowering, and cultivar flowering date characteristics are well known, there is little information on the effects of other factors, such as N fertiliser and grazing intensity, on flowering behaviour. We compared tiller dynamics of early flowering, endophyte-free, perennial ryegrass cultivars ('Ellett' and 'Grasslands Ruanui') under two N fertiliser and irrigation levels, and dairy cow grazing. In the first flowering period after sowing (October 1996-January 1997), 'Ellett' ryegrass averaged 19.5% reproductive tillers in the total tiller population, while 'Grasslands Ruanui' ryegrass averaged 13.0%. In the second season (September 1997-January 1998), 17.1% of 'Ellett' tillers were reproductive, compared with only 7.8% for 'Grasslands Ruanui'. There was a cultivar × N interaction in summer 1997/98, with N increasing *Author for correspondence. Email: errol.thom@dexcel.co.nz the percentage of reproductive tillers in 'Ellett', but decreasing them in 'Grasslands Ruanui'. The irrigation treatment did not affect flowering behaviour. In another study, lax grazing of endophyte-infected 'Ellett' ryegrass resulted in 7% of total tillers flowering compared with 34% under hard grazing. The importance of considering the effects of latitude on flowering behaviour is discussed.

Demografia de perfilhos basilares em pastagem de Brachiaria decumbens adubada com nitrogênio

“…O número de perfilhos em função das doses de N se ajustou ao modelo linear somente no período de fevereiro a abril (Tabela 7), o que reflete a associação entre o nutriente e as condições climáticas favoráveis, como observado por outros autores em gramíneas de clima temperado (Langer, 1963;Nelson & Zarrough, 1981;McKenzie, 1998;Bahmani et al, 2002) e em gramíneas de clima tropical (Alexandrino Tabela 5 -Taxas de sobrevivência de perfilhos basilares (perfilhos/100 perfilhos) em pastagem de Brachiaria decumbens adubadas com quatro doses de N …”

“…Segundo Langer (1963), o perfilhamento é influenciado por fatores de ambiente, destacando-se a temperatura e o suprimento de água e de nutrientes, principalmente de nitrogênio (N), que assume papel importante no crescimento e na produção das plantas forrageiras, pois seu suprimento eleva o número de perfilhos por planta (Langer, 1963;McKenzie, 1998;Alexandrino et al, 1999;Garcez Neto et al, 2002;Bahmani et al, 2002). Nabinger (1996) atribuiu o efeito positivo do N sobre o perfilhamento à maior rapidez de formação das gemas axilares e à iniciação dos perfilhos correspondentes.…”

The relationship between tiller appearance in spring and contribution to dry‐matter yield in perennial ryegrass (Lolium perenne L.) cultivars differing in heading date

“…Tillers produced in the previous autumn are more likely to flower in the following spring than those produced during the winter (Korte, 1986). However the probability of a tiller flowering, which has either appeared in the previous year or in early spring of the current year, differs between cultivars, even when their heading dates are similar (Bahmani et al, 2002). Therefore, study of the effect of heading date on flowering and tiller development in spring needs to include a number of cultivars in each group to reduce the likelihood of flowering propensity and time of heading being confounded.…”

“…Tillers produced in the previous autumn are more likely to flower in the following spring than those produced during the winter (Korte, 1986). However the probability of a tiller flowering, which has either appeared in the previous year or in early spring of the current year, differs between cultivars, even when their heading dates are similar (Bahmani et al. , 2002).…”

Relationship of tillering and morphological characteristics of two perennial ryegrass lines to “pulling” when grazed by dairy cows

“…Perennial ryegrass usually responds strongly to N fertiliser by increasing vegetative tiller number and total herbage yield (Harris et al 1996;McKenzie 1998;Waller & Sale 2001), although N fertiliser (Bahmani et al 2002) can also modify reproductive tillering in some cultivars. Variations in the expected seasonal tillering pattern of the ryegrass lines may partially reflect the grazing management of the trial sites.…”