不同密度紧凑型油菜的源库特征及与收获指数的相关研究

旨在为油菜株型育种和机械化栽培提供理论和技术依据。选用3个不同类型的紧凑型油菜常规品种,以松散型油菜杂交种‘秦优7号’为对照,研究了在15万、30万、45万、60万、75万、90万株/hm²密度下各品系的库源特征及其与收获指数的关系。结果表明,紧凑型油菜单株在不同密度下的库源特征与对照松散型相同,单株根、茎、枝、壳干重,角粒数和单株角果数随种植密度的增加而降低,且低密度显著高于高密度;千粒重随密度的变化不大。紧凑型油菜的生物学产量和经济产量随种植密度的增加而增加,松散型油菜随种植密度的增加而下降。说明紧凑型油菜适宜密植和机械化收获。收获指数对密度的响应在两类型品种表现一致,最低密度15万株/hm²增加到30万株/hm²时达到峰值,以后随着种植密度的继续增加而降低。收获指数与茎+枝+壳干重之和,与库性状角粒数、角果数、千粒重、单株产量,与库源关系的粒根比、粒茎比、粒枝比、粒壳比显著正相关,说明要提高收获指数不仅要扩“源”增“库”,还要协调库源的合理分配比例。

Compact Rapeseed Under Different Densities: Sink-source Characteristics and Their Correlation with Harvest Index

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.