迟播和密度对不同油菜品种抗倒伏及产量的影响

Effects of sowing date and density on lodging resistance and yield of different rapeseed cultivars

研究迟播和密度对油菜抗倒伏及产量的影响,为油菜机械化生产提供理论及技术支撑。以陕油28、秦优28及秦优7号为供试品种,分别设置3个播期(T1:9月24日、T2:10月1日、T3:10月8日)和3个密度(D1:22.5万株hm^(-2)、D2:45.0万株hm^(-2)、67.5万株hm^(-2))处理,分析其产量及构成因素、倒伏相关指标、茎秆主要成分含量及显微结构等指标。结果表明:(1) T1、T2下,随种植密度增加, 3个品种单株产量均下降,群体产量均先增后降,倒伏指数均先降后增,维管束与茎秆横截面积均下降,维管束面积/茎秆横截面积、茎秆木质素与纤维素含量均先增后降, D2时群体产量最大,倒伏指数最小,产量与抗倒伏能力协同增加。迟播条件(T3)下,随密度增加, 3个品种单株产量、倒伏指数、茎秆木质素及纤维素含量、地上部鲜重、维管束面积及茎秆横截面积及二者之比均显著下降,群体产量及抗倒性增强,木质素含量与茎秆抗倒伏能力显著正相关,群体产量及材料抗倒能力在D3时达最大值。与正常播期(T1)相比,迟播条件(T3)下,各密度下,3个品种单株角果数、每角粒数、单株产量及群体产量、地上鲜重、倒伏指数均显著下降,但抗倒伏能力增强。(2)正常播期(T1)下, 3个品种群体产量最高时,种植密度均为45.0万株hm^(-2)。迟播(T3)后,密度67.5万株hm^(-2)时3个品种产量均最高,其中陕油28的耐密性与耐迟播性最佳。综上所述,迟播条件下,选择耐密及耐迟播品种,并适度增加密度,可弥补单产不足,显著提高茎秆木质素及纤维素含量、增强油菜抗倒伏能力,有效协调高产与倒伏间的矛盾,通过以密补迟实现迟播油菜高产抗倒。

To study the effects of late sowing and density on the lodging resistance and yield of rapeseed,and to provide the theo-retical and technical support for the mechanized production of rapeseed,using three canola varieties(Shaanyou 28,Qinyou 28,and Qinyou 7)as the experimental materials,three sowing dates(T1:September 24,T2:October 1,and T3:October 8),and three densities(D1:225,000 plants hm^(–2),D2:450,000 plants hm^(–2),and D3:675,000 plants hm^(–2))were set up to analyze the yield and constituent factors,the indexes related to lodging,the main components of the stem and the microstructure of the stem.The results showed that:(1)Under T1 and T2 treatments,with the increase of plant density,the yield of each plant of the three varieties de-creased,the group yield increased first and then decreased,the lodging index decreased first and then increased,the vascular bun-dle and stem cross-sectional area decreased,the vascular bundle area/stem cross-sectional area,stem lignin,and cellulose content increased first and then decreased,the group yield was the largest at D2,while the lodging index was the smallest,and the yield and lodging resistance increased synergistically.Under the late sowing condition(T3),with the increase of density,the yield,lodging index,stem lignin,and cellulose content,above-ground fresh weight,vascular bundle area,stem cross-sectional area,and their ratios of the three cultivars decreased significantly,the group yield and lodging resistance increased,the lignin content was significantly positively correlated with the lodging resistance of stems,and the population yield and material resistance reached the maximum at D3.Compared with the normal sowing period(T1),the effective pods per plant,seeds per pod,yield per plant,population yield,and above-ground fresh weight the lodging index of each plant decreased significantly under the late sowing condition(T3),but the lodging resistance was enhanced.(2)Under the normal sowing period(T1),when the yield of the three variety groups was the highest,planting density was 450,000 plants hm^(–2).When the sowing date was delayed from T1 to T3,the yield of the three varieties was the highest at the density of 675,000 plants hm^(–2),among which Shaanyou 28 had the best density tolerance and late sowing resistance.In conclusion,under the late sowing condition,selecting dense and late sowing tolerant va-rieties and moderately increasing the density can compensate for the lack of yield,significantly increase the lignin and cellulose content of the stem,enhance the lodging resistance of rapeseed,effectively coordinate the contradiction between high yield and lodging,and achieve high yield and lodging resistance of late sowing rapeseed by compensating late with dense.