%A JIN Rong,LI Zhong,YANG Yun,ZHOU Fang,DU Lun-Jing,LI Xiao-Long,KONG Fan-Lei,YUAN Ji-Chao %T Effects of density and row spacing on population light distribution and male and female spike differentiation of summer maize in hilly area of central Sichuan %0 Journal Article %D 2020 %J Acta Agronomica Sinica %R 10.3724/SP.J.1006.2020.93034 %P 614-630 %V 46 %N 4 %U {https://zwxb.chinacrops.org/CN/abstract/article_6868.shtml} %8 2020-04-12 %X

In order to facilitate mechanical production, the corn production in parts of central Sichuan has gradually changed from the intercropping spring planting to the net summer planting. In order to clarify the population structure of the net summer maize for high yield and suitable for mechanization in the region, the effects of density and row spacing on population light distribution and male and female spike differentiation of summer maize were studied with two-factor splitting test design. With the increase of planting density, the maize effective panicle increased, with a gradually decreased increase range, and finally decreased due to the increase of empty stalk and lodging. With the density increased, the angle between stem and leaf and the opening angle decreased, the leaf orientation value increased, the group transmittance decreased significantly, the extinction coefficient increased, and the spike length and middle diameter of the male and female spikes at the panicle differentiation and floret differentiation stages, the tassel spindle length and pairs spikelet number at the silking stage, as well as the total small flower number, the silking floret number, the fertilized floret number and the fertilization rate per plant decreased, while the degraded floret number, the abortive flower number and the abortion rate increased, which eventually led maize bald ear tip become longer, the grain number per panicle and 100-grain weight decreased significantly. With the increase of planting density, the yield increased first and then decreased, with the highest yield under 67,500 plants hm -2. For the average yield of two years, the treatment of 67,500 plants hm -2 had a significant increase of 17.00% and 14.03% compared with the treatments of 45,000 and 90,000 plants hm -2, respectively. In addition, under the density of 45,000 and 67,500 plants hm -2 for two years, the equal row spacing was better than the corresponding wide and narrow rows, and the maize plant type was compact in 60 cm row spacing treatment, which improved group light conditions and fertilization rate per plant, reduced small flower abortion rate, and increased maize yield. Under the density of 90,000 plants hm -2 in 2018, (110+50) cm wide and narrow treatment improved the ventilation and light transmission conditions in the field, promoted the differentiation of female and male ears, and increased the maize yield. Therefore, the high-yield cultivation of summer maize in the central Sichuan area should be performed by properly reducing row spacing and increasing plant density, which are suggested as (60+60) cm and 67,500 plants hm -2 respectively.