种植密度对不同穗型冬小麦品种结实特性和产量的影响

为了明确种植密度对冬小麦结实特性和产量的影响，于2020-2021年以大穗型品种衡观35和多穗型品种济麦22为试验材料，设置4个种植密度水平，分别为每公顷基本苗180万（D180）、300万（D300）、420万（D420）和540万（D540）株，比较分析了不同种植密度下冬小麦小花结实、籽粒空间分布特征和产量的差异。结果表明，随着种植密度的降低，衡观35主茎穗上部和I分蘖穗下部、济麦22主茎和I分蘖穗中上部小穗位的结实粒数呈增加的趋势。降低种植密度促进了两个品种穗中部小穗位弱势小花、上部和下部小穗位强势小花的结实。衡观35主茎穗中上部和I分蘖穗中部小穗位的结实粒数均高于济麦22。开花期穗干重与可孕小花数呈显著正相关。低种植密度处理下开花期穗干重的增加为其获得较高的穗粒数奠定了良好的物质基础。种植密度对千粒重影响不显著，但显著降低了衡观35的穗数。由于产量构成三要素的协调作用，两个品种均在D300处理下获得了最高产量，但与其余种植密度处理间差异均不显著。综合来看，在保证穗数的前提下，适当降低种植密度会促进冬小麦主茎和分蘖穗结实，进而增加穗粒数和产量，可节约生产成本，有利于冬小麦绿色高产高效生产。

Effects of Planting Density on Grain Setting Characteristics and Grain Yield of Winter Wheat Cultivars with Two Spike Types

In order to investigate the effects of planting density on grain setting characteristics and grain yield of winter wheat,Hengguan 35(a large-spike cultivar) and Jimai 22(a multi-spike cultivar) were used in 2020-2021. Four densities were conducted: 1.8×10⁶(D180),3.0×10⁶(D300),4.2×10⁶(D420),and 5.4×10⁶(D540) plants·hm^-2. The effect of densities on grain setting characteristics, grain spatial distribution and yield were studied. The results showed that the kernel number in upper spikelets of main stem and in basal spikelets of I tiller of Hengguan 35 increased with the decrease of planting density.In addition, the kernel number in middle and upper spikelets of main stem and I tiller of Jimai 22 also increased with the decrease of density.Reducing density effectively promoted the grain setting of inferior florets in middle spikelets and superior florets in upper and basal spikelets. The kernel number in middle and upper spikelets of main stem of Hengguan 35 was higher than that of Jimai 22. Meanwhile, the kernel number in the middle spikelets of I tiller of Hengguan 35 was also higher than that of Jimai 22.The ear weight at anthesis was positively correlated with the number of fertile florets. The increase in spike weight at anthesis under low plant density provided sufficient nutrition for the development of florets to grains. There was no significant effect of plant density on 1 000-grain weight. However, the spikes of Hengguan 35 decreased significantly with the increase of density. D300 achieved the highest grain yield.Whereas, there was no significant difference in yield between the four plant densities of each cultivar. In conclusion,properly reducing plant density saved cost,and realized green, high yield and high efficiency of winter wheat production by increasing kernel number on the promise of ensuring spike number at maturity.