Optimizing planting density and variety allocation synergistically to improve maize yield and resource utilization efficiency in different agroecological zones of southwest China

Abstract Effective matching between the heat demand of maize varieties and regional resources is essential for achieving high yields. To evaluate the effects of planting density and variety allocation on maize yield and resource utilization efficiency in the different agroecological zones of southwest China, we conducted experiments in five agroecological zones in Guizhou Province. When comparing the same planting density at different sites, grain yield and dry matter accumulation decreased in the following order: Weining, Bijie > Tongren > Anshun and Xingren. Jinyu 838 and Xingzhongyu 801 had a higher yield (12.91 and 12.86 t ha −1 ) at 82500 plants ha −1 at Weining. The production efficiency for effective accumulated temperature (g m −2 [°C·day] −1 ) at Weining was higher than that at the other sites. However, the production efficiency for cumulative solar radiation (g MJ −1 ) at Weining was lower than that at the Anshun and Tongren sites. Moreover, grain yield and dry matter accumulation were positively correlated with the diurnal temperature range, accumulated solar radiation, and number of growing days. Therefore, by optimizing variety and planting density, maize yield and resource utilization efficiency can be improved in areas with large diurnal temperature and high accumulated solar radiation in southwest China.