We investigated how the responses of grain yield of maize to planting density depended on planting pattern (twin row, TR; narrow row, NR; narrow twin row, NTR; compared with conventional row (CR) cultivation) over 2 years using cultivars with relative maturity of 93 days. Grain yields were higher in order of NTR ≥ TR ≥ NR ≥ CR in all planting densities. Changes in grain yield and total dry matter yield with planting density followed significant negative quadratic regression curves in all planting patterns, increased with dense planting from 9.7 to 10.4 planting density and decreased thereafter. Changes in number of grains per ear and hundred grain weight with planting density followed significant negative linear regression in all planting pattern, and number of grain per ear, hundred grain weight and harvest index decreased with dense planting. The quadratic coefficient of the quadratic regression model, which indicates the changeability of the planting density response of grain yield, was lowest for NTR, followed by TR, NR and CR. The decline in number of grains per ear in response to increasing planting density for different planting patterns was NTR ≤ TR ≤ NR ≤ CR. The planting density response of total dry matter yield closely follows that of the grain yield in all planting pattern. But decrease in harvest index due to increased planting density for different planting patterns was lowest for NTR, followed by TR, NR and CR. Considering the relationship of grain yield to their related traits, the improved stability of grain yield for the specific planting patterns from the fact that the decline in number of grains per ear for different planting patterns is NTR < TR ≤ NR < CR. The specific planting patterns moderate the decline in harvest index and number of grains per ear with increasing planting density by enabling the maintenance of greater inter‐individual distance a given planting density.

中文翻译：

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玉米早熟双窄行栽培中产量对种植密度的响应

我们调查了在两年内使用相对栽培的玉米品种，玉米籽粒产量对种植密度的响应如何取决于种植方式（双行，TR；窄行，NR；窄双行，NTR；与常规行（CR）相比）。成熟期93天。在所有种植密度下，单产都高于NTR≥TR≥NR≥CR。在所有种植方式下，籽粒产量和总干物质产量随种植密度的变化均遵循显着的二次回归曲线，密实种植从9.7增加到10.4种植密度增加，此后降低。在所有种植方式下，每穗籽粒数和百粒重随种植密度的变化均呈显着的负线性回归，而每穗粒数，百粒重和收获指数随密植度而降低。二次回归模型的二次系数（表示谷物产量的种植密度响应的变化性）对于NTR最低，其次是TR，NR和CR。对于不同种植方式，随着种植密度的增加，每穗谷物的减少量为NTR≤TR≤NR≤CR。在所有种植方式下，总干物质产量的种植密度响应都与谷物产量的响应密切相关。但是，由于不同种植方式的种植密度增加而导致的收成指数下降最低的是NTR，其次是TR，NR和CR。考虑到谷物产量与其相关性状的关系，特定种植模式下谷物产量的稳定性得到改善，这是由于不同种植模式下每穗穗粒数的下降是NTR <TR≤NR <CR。