Plant growth regulators to manipulate oat stands

Abstract

Plant growth regulators (PGRs) are exogenously applied chemicals that alter plant metabolism, cell division, cell enlargement, growth and development by regulating plant hormones or other biological signals. For example, some PGRs regulate stem elongation by inhibiting biosynthesis of gibberellins or through releasing ethylene. PGR effects are widely studied and reported on barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.), whereas there are only a few reports addressing oat (Avena sativa L.). This is likely to be a result of smaller acreage and lower intensity of oat management and production and hence a reduced need for stem shortening by PGRs. However, this is not the case for all cereal producing regions and there exists a need to understand the potential application of PGRs to oat production. This paper represents a review of the potential of PGRs to regulate stem elongation and other biological traits governing plant stand structure and yield components, with special emphasis on oat and its responses to PGRs. Yield improvement requires more heads per unit land area, more grains per head or heavier grains. Of these yield-determining parameters, the number of head bearing tillers and grain numbers per head, compared with grain weight, are more likely to be improved by PGR application. In the absence of lodging, PGR may reduce grain yield due to potential reduction in mean grain weight and/or grain number. Cultivation systems aiming at extensive yields with intensive use of inputs likely benefit from PGR applications more often compared with low or moderate input cultivation, for which cost effectiveness of PGRs is not frequently reached.

Responses of developmental yield formation processes in oats to variety, nitrogen, seed rate and plant growth regulator and their relationship to quality

“…Increases in number of grains/ panicle have been reported (Leitch & Hayes 1989). However, in agreement with the experiments reported in the present paper, Rajala (2004), in a comprehensive review of plant growth regulator effects on oats, found little evidence to suggest consistent promotional effects of chlormequat chloride, on the components of yield. Numbers of aborted primary grains were unaffected by chlormequat chloride.…”

Oat (Avena sativa) yield and grain fill responses to varying agronomic and weather factors

“…Where additional grain sites were not stimulated by the application of PGRs it is probable that grain weight was reduced due to assimilate being redirected from grain sites. These results fit in with the theory suggested by Rajala (2004) who, after a wide-ranging review, concluded that varying responses in oat crops to PGR application were case specific. Although the application of PGR can exert positive effects on yield components, these effects are not as reliable or consistent as other agronomic factors.…”

Redução do acamamento em aveia-branca com uso do regulador de crescimento etil-trinexapac

“…Em cereais de inverno, o princípio ativo etil-trinexapac vem sendo utilizado em lavouras comerciais no Brasil, e seu uso tem sido indicado para a redução do crescimento das plantas em altura e para o fortalecimento dos entrenós. Embora haja escassez de informações científicas sobre os efeitos do uso de reguladores de crescimento na cultura da aveia-branca, essa prática pode ser uma alternativa para minimizar os efeitos negativos do acamamento de plantas (Rajala & Peltonen-Sainio, 2001;Rajala, 2004;Witkowicz, 2010).…”