Abstract:

The aim is to provide the theoretical and technical support for plant-type breeding and mechanized cultivation of rapeseed. 3 different conventional compact varieties and a hybrid loose variety ‘Qinyou 7’ (as control) were studied under varying planting densities (15×10 ⁴, 30×10⁴, 45×10⁴, 60×10⁴, 75×10⁴ and 90×10⁴ plants/hm²). The sink-source characteristics and their relationship with harvest index of compact rapeseed were explored. The results showed that the sink-source characteristics of compact rapeseed single plant were similar with the control. Root, stem dry weight, branches dry weight and shell dry weight, number of siliques, siliques number per plant decreased significantly with the increasing density, and were higher under the low density than under the high density. While thousand-seed weight changed a little along with the densities. The biological yield and economic yield of compact rapeseed increased with the increasing density, while those of the loose rapeseed decreased along with the increasing density, which indicated that compact rapeseed was suitable for compact density and mechanized harvesting. Response of harvest index to different densities was the same between compact and loose types. The highest harvest index was obtained with density increasing from 15×10⁴ plants/hm² to 30×10⁴ plants/hm², and it decreased with density increasing continuously. Correlation analysis showed that there was a significantly positive correlation between harvest index and stem+branches+shell dry weight, number of siliques, siliques number per plant, thousand-seed weight, yield per plant, yield per plant/root dry weight, yield per plant/ stem dry weight, yield per plant/branches dry weight and yield per plant/shell dry weight. Thus, the increase of harvest index of rapeseed needs increasing sink and source, and keeping a rational proportion between sink and source.

Key words: rapeseed, compact type, sink-source relationship, harvest index, correlation analysis