以郑单958(ZD958)和登海661(DH661)为试验材料,研究在4.5万、7.5万、10.5万株/hm² 种植密度下玉米上部及中下部子粒灌浆特性和粒重的关系。结果表明,穗粒数和千粒重是决定子粒最终产量的重要因素,两者均随着密度的增加而显著降低。同一密度下,穗位层光照自开花当天(0 d)先降低后升高,总体呈“高-低-高”的变化趋势,底层光照则持续升高。上部子粒的起始生长势、灌浆速率、胚乳细胞数及淀粉含量均低于中下部子粒。相关及通径分析表明,影响粒重的主要因素是灌浆速率、胚乳细胞数目和淀粉含量,其相关系数分别为0.959 66^**、0.981 91^**和0.877 76^*。光照(包括穗位层和底层)主要通过灌浆速率和淀粉含量来间接影响粒重。

Two cultivars ZD958 and DH661 were used to analyze the effects of different planting densities on grain filling characteristics and grain weight in apical and mid-basal kernel positions of maize. The results showed that both grain number and kernel weight decreased with the increase of density and they determined the grain yield together. At the same density, ear layer transmission declined since pollination(0 d) and then increased slowly while that of bottom kept increasing since pollination. The initial division power(R₀), division rate, endosperm cell number and starch content of apical kernels were lower than these of mid-basal kernels. Correlation and path analysis showed that main factors that affected grain weight were division rate, endosperm number and starch content, their correlation coefficients were 0.959 66^**, 0.981 91^** and 0.877 76^*, respectively. Light transmission, including ear layer and bottom, affected grain weight via division rate and starch content.

国家自然科学基金(31171497);玉米现代产业技术体系(nyhyzx07-003);国家重大基础研究项目(2011CB10010);农业部玉米产业技术体系(CARS-02)