Analysis of early vigor in twenty modern cultivars of bread wheat (Triticum aestivum L.)

M.L. MAYDUP; CORINA, GRACIANO; E.A. TAMBUSSI; GUIAMET, JUAN JOSE

CROP & PASTURE SCIENCE

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2012 p. 987 - 996

1836-5795

Abstract. Fast development of seedling leaf area is a relevant trait in order to increase early resource acquisition. The use ofsemi-dwarf genotypes of wheat has decreased early vigour of modern cultivars. We studied early vigour of 20 cultivarscropped in Argentina, and our main objectives were: (i) to analyse the genotypic variability in early vigour; (ii) to studymorphological traits that can be good indicators of early vigour, such as seed mass, leaf width, and specific leaf area; and (iii) todetermine whether increased dry mass allocation to roots impacts negatively on early vigour. Experiments with non-sizeselectedand size-selected seeds were carried out in a greenhouse.Afield trial was also conducted in order to test the reliabilityof the greenhouse results. Seeds mass was the main parameter related to early vigour. However, results from the experimentwith seeds selected by size (45?50 mg seed?1) showed that seed mass per se only partially explains early vigour, since asignificant coefficient of determination was observed between the seedling leaf area of each cultivar in both experiments (i.e.with randomly chosen or size-selected seeds).Weobserved a high coefficient of determination between net assimilation rate and changes in the ranking of early vigour ofthe cultivars with time after transplant. Root biomass was positively correlated with leaf area, indicating that the traits were notmutually exclusive. We built simple models by multiple regression to predict early vigour, including some parameters thatwere easy to measure. Seed mass and leaf width taken together showed better fit than seed mass or leaf width alone.Wefounda significant coefficient of determination between early vigour in greenhouse and field experiments; thus, screening for earlyvigour under semi-controlled conditions may be feasible.