Effects of density on population quality and yield of peanut with different plant types under the mode of single-seed precision sowing

In order to clarify the effect of planting density on the population quality of peanut with different plant types under the mode of single-seed precision sowing, this experiment were carried out with two plant-types (erect big peanut variety “Huayu 22” and semi-creeping big peanut variety “Huayu 9513”), three densities (75,000 plants hm⁻², 150,000 plants hm⁻², and 225,000 plants hm⁻²). Yield, photosynthetic product accumulation and distribution, leaf area index, plant characteristics and grain leaf ratio were studied. The results were as follows: (1) With the increase of density, the pod yield of “Huayu 22” increased, while that of “Huayu 9513” increased first and then decreased, in addition, the optimum planting density of “Huayu 9513” was lower than that of “Huayu 22”. (2) The population dry weight of “Huayu 22” increased with the increase of density during the growth period, and the greater the density, the smaller the increase range. While the population dry weight of “Huayu 9513” increased with the increase of density at seedling stage, increased first and then decreased with the increase of density after flower pegging stage, and the dry weight of D2 density was the largest. With the increase of density, the distribution proportion of dry matter in roots increased and that in fruit needles decreased; “Huayu 9513” and “Huayu 22” had the probably same dry weight at harvest stage, while the distribution proportion of dry matter to pods was less, and the economic coefficient and grain to leaf were lower. The leaf area index and leaf area duration of peanut increased with the increase of density at the early growth stage, and the increase of “Huayu 9513” was higher than that of “Huayu 22”. The leaf area index and leaf area duration of “Huayu 9513” was not significantly different from that of “Huayu 22” before pod setting stage, however from pod setting stage to harvest stage it was significantly higher than that of “Huayu 22”. (3) The number of lateral branches and fruit branches per plant decreased with the increase of density in the harvest period, while that of the population increased with the increase of density. (4) The correlation analysis showed that there were positive or significant positive correlation between peanut pod yield and dry matter accumulation after pod setting stage, especially dry matter accumulation at pod fulling stage, leaf area duration, plant dry weight, and leaf area index at harvest stage. In conclusion, density showed different effects on the population quality of peanut with different plant types, erect peanut “Huayu 22” showed good density tolerance and the optimum density was higher, while semi-creeping peanut “Huayu 9513” showed poor density tolerance. The optimum density of “Huayu 9513” was lower.