种植密度对高粱群体生理指标及产量影响

为明确种植密度与高粱产量和产量构成因素以及群体光合生理指标的关系，以极早熟高粱杂交种‘通早2’为试验作物，采用大田试验方法，研究了不同种植密度对高粱生长、产量及其构成因素、及群体光合生理指标的影响。试验采用随机区组设计，3次重复。试验设15万株/hm2、18万株/hm2、21万株/hm2、24万株/hm2和27万株/hm25个种植密度，结果表明：随种植密度的增加，株高增高，茎粗变细。单株干物质量、群体净同化率、群体生长率显著下降。叶面积指数、叶片光合势及总光合势随种植密度的增加而显著上升；种植密度在15万~21万株/hm2时，籽粒产量随种植密度的增加而增加，种植密度持续增加，籽粒产量呈下降趋势，且各处理之间籽粒产量差异显著。随着种植密度增加，单位面积穗数相应增加，单株穗粒重、千粒重随种植密度的增加而逐渐降低，且各处理之间达到显著水平。本试验研究结果表明，‘通早2’种植密度为21万株/hm2，株行距9.5 cm×60 cm时，能更好地协调群体结构，使籽粒产量达到较高水平。

Effects of Planting Density on Population Physiological Indices and Yield of Sorghum

The aim is to determine the relationships between planting density and yield, component factors of yield and population physiological indices of sorghum. The extremely early-maturity hybrid‘Tongzao No. 2’ was used as the material in a field experiment. The randomized block design was adopted with three repeats. 5 planting densities (150-thousand, 180-thousand, 210-thousand, 240-thousand, 270-thousand plants/hm2) were employed. The results showed that, the plant height of sorghum was increased and the stem diameter became thinner along with the increasing planting density, but the dry matter weight per plant, population net assimilation rate, population growth rate were significantly decreased as planting density increased. The leaf area index, leaf area duration and the total leaf area duration were significant increased with the increasing planting density. When the planting density was at the range of 150-thousand to 210-thousand plants/hm2, the grain yield significantly increased with the increasing planting density. Along with the increasing planting density, the grain yield showed a downward trend, and there was significant difference of grain yield among the treatments. Panicle number per unit area increased with the increasing planting density, but the grain weight per plant and 1000-grain weight decreased with the increasing planting density, and the difference among treatments was significant. It is concluded that, when the planting density is 210-thousand plants/hm2, the spacing is 9.5 cm× 60 cm, the sorghum hybrid‘Tongzao No. 2’could coordinate the population structure well and obtain higher grain yield.