Semi-dwarf genotypes-a chance to reduce the N problem after oilseed rape?
In NW Europe oilseed rape (OSR) is often used as preceding crop for winter wheat. Due to its low N harvest index and to favorable soil conditions, large N amounts remained in the soil, which, however, cannot completely be taken up by the subsequent wheat crop and increases the risk of N leaching into the groundwater during the following winter. Several approaches to reduce N leaching have been discussed (e.g. growing of catch crops, reducing soil tillage in autumn, reducing N fertilization), however, the farmers acceptance remains low due to economical losses. In the last years, OSR semi-dwarf genotypes were developed. We assumed that semi-dwarf genotypes accumulate less vegetative biomass and need therefore less nitrogen to achieve yield maximum compared to conventional hybrids or open pollinating varieties, which in consequence reduce the risk of N leaching. In order to test this working hypothesis, a field trial was performed in 2003/04 and 2004/05 at the Hohenschulen Experimental Station located near Kiel in NW Germany. Four varieties (Express, Talent, Trabant and Belcanto as semi-dwarf genotype), two seeding date (mid of August, beginning of September) and eight mineral N fertilization (0 to 240 kg N ha-1) were varied. On average, the semi-dwarf genotype Belcanto achieved significantly less seed yield (4.44 t ha-1) than the other varieties (4.65-4.88 t ha-1), however, all tested varieties needed similar N fertilization for their yield maximum. In addition, N offtake by the seeds did not differ. No interaction between genotype and N treatment occurred. Detailed analysis of dry matter accumulation and N uptake during the growth period revealed only small differences between the varieties on average of all N treatments and both years. At harvest, Belcanto produced more pods m-2 and a slightly higher thousand seed weight. However, harvest index and N harvest index were similar for all genotypes. We conclude that despite its lower plant height the semi-dwarf genotype Belcanto does not provide the opportunity to reduce the N problem in OSR based rotations.
Oilseed rape Brassica napus semi-dwarf genotype nitrate problem yield harvest index
Klaus Sieling Henning Kage
Institute of Crop Science and Plant Breeding, Christian-Albrechts-University 24118 Kiel, Germany
国际会议
第十二届国际油菜大会( The 12th International Rapeseed Congress)
武汉
英文
1025-1028
2007-03-26（万方平台首次上网日期，不代表论文的发表时间）