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Effects of Nitrogen and Plant Density on Growth, Yield and Chemical Composition of Two Winter Wheat (Triticum aestivum L.) Cultivars |
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| Authors: | J Ellen |
| Institution: | Department of Field Crops and Grassland Science, Wageningen Agricultural University, Wageningen, Netherlands |
| Abstract: | A field study was conducted on the winter wheat cultivars Arminda and Okapi , using two seed rates (80 and 160 kg/ha) and three N applications (40, 80 and 120 kg/ha). The cultivars did not differ in total dry matter production but did differ in grain yield. The difference in grain yield was mainly attributable to a higher harvest index (HI). Increased plant density reduced HI; it resulted in more shoots per m A higher rate of N increased total dry matter production and grain yield, except in Okapi at the high plant density. The number of kernels per ear increased, but 1000-grain weight fell. The higher the N applications, the higher the N-content of the roots was. Total N yield was greater in Arminda than in Okapi. The cultivars differed in the amount of nitrogen they took up after anthesis. The content of water-soluble carbohydrates (WSC) differed between the cultivars, N treatments and growth stages. Carbohydrate formed before anthesis accounted for 23 % of Arminda's grain yield and for 10 % of Okapi's grain yield. The content of cell-wall constituents (CWC) depended on cultivar, growth stage and the rate of the N dressing. Differences in CWC were more pronounced in Arminda than in Okapi. During leaf, stem and ear development there was a strong increase in content and amount of CWC. Concomitantly, WSC decreased. This implies that a large consumption of WSC is necessary for the formation of CWC. The competition for the WSC, necessary for CWC and shoot and ear development influences kernel initiation. Per unit of dry matter Okapi contained more CWC than Arminda. This was not in agreement with differences in straw sturdiness. |
| Keywords: | development yield components water-soluble carbohydrates cell-wall constituents |