种植密度与缩节胺用量对76 cm等行距棉花株型结构及产量的影响

于2021—2022年在76 cm等行距种植方式下，采用裂区设计，设种植密度为主因素，分别为15.00(M1)、20.25(M2)、25.50万株·hm^-2(M3);缩节胺用量为副因素，分别为195 (D1)、390 (D2)、585 g·hm^-2(D3),研究不同种植密度与缩节胺用量对棉花株型结构、籽棉产量及其构成因素的影响，以筛选适宜76 cm等行距种植模式棉花产量提高的种植密度与缩节胺用量组合。结果表明：缩节胺用量相同时，降低种植密度会提高棉花株高7.09%～21.66%、茎粗4.36%～13.02%、株宽5.76%～18.69%,增加果枝始节高度、主茎节间长度、果枝数和果枝长度；种植密度对果枝始节位与果枝夹角影响不显著。种植密度相同时，降低缩节胺用量会增加棉花株高7.01%～21.83%、株宽4.61%～9.01%、果枝数1～2台，并有效增加果枝始节高度、果枝始节位、主茎节间长度、果枝长度与果枝夹角，但会降低棉花茎粗3.39%～8.30%。籽棉产量随密度与缩节胺用量的增加呈先增后减的变化趋势，M2D2处理籽棉产量最高，两年分别为6 6...

Effects of planting density and DPC dosage on plant structure and yield of cotton under 76 cm equidistant cultivation

During 2021 to 2022, under 76 cm equidistant cultivation, a split\|zone design was used to set planting density as the main factor, which was 150 000 (M1), 202 500 (M2), and 255 000 plants·hm^-2(M3) respectively, and the dosage of DPC (Mepiquat chloride) as the sub\|factor, which was 195 (D1), 390 (D2), and 585 g·hm^-2 (D3).The effects of different planting densities and DPC dosage on cotton plant structure, seed cotton yield and its components were investigated, in order to screen suitable combinations of planting density and DPC dosage for improving cotton yield under 76 cm spacing planting pattern. The results showed that, when the same amount of DPC was used, reducing planting density increased the height of cotton plants by 7.09%~21.66%, stems thickness by 4.36%~13.02%, plants width by 5.76%~18.69%, increased the height of the first node of the fruit branches, the length between the main stem internodes, the number of fruit branches, and the length of fruit branches. The planting density has no significant effect on the length of the first node of the fruit branches and the angle between the fruit branches. When planting density was the same, reducing the dosage of DPC increased cotton plant height by 7.01%~21.83%, plant width by 4.61%~9.01%, the number of fruiting branches by 1~2, and effectively increased the height of fruiting branch initiation, fruiting branch initiation node, the length of the main stem internode, the length of fruiting branches and the angle of the fruiting branches, but it reduced the cotton stem thickness by 3.39%~8.30%. Seed cotton yield with the increase in density and the amount of DPC showed a trend of increasing and then decreasing. M2D2 treatment seed cotton yield was the highest, two years were 6 614.09 kg·hm^-2 and 7 339.48 kg·hm^-2, compared with the lowest yield in the same year the treatment M1D1, increased by 19.63% and 22.67%, respectively. In conclusion, the combination of cotton planting density of 202 500 plants·hm^-2 with spraying of 390 g·hm^-2 of DPC was the best in 76 cm equidistant cultivation, which was favorable to growth and development of cotton and yield improvement.