Abstract: We investigated the effect of single seed directional sowing on the growth and development of peanut hypocotyl, plant photosynthetic performance, dry matter accumulation, senescence characteristics and yield of a peanut variety, Huayu 25. There are several treatments in the experiment, including single-seed random sowing (RS), radicle down (RD), radicle flat (RF) and radicle up (RU) treatments, with double seed sowing cleaning stem base soil (QK) as the control. The results showed that under the condition of single seed directional sowing, RD could increase the growth rate of peanut hypocotyl, shorten the emergence time, increase the emergence rate and cotyledon emergence rate, and had faster plant growth rate, higher leaf area index in the early stage of peanut growth, and an increased dry matter accumulation. The pod yield under RD was 8.1%, 14.4%, and 18.1% higher than that of RF, RS, and RU, respectively. Furthermore, RD significantly increased soluble protein content and the activities of superoxide dismutase, peroxidase and catalase, and reduced malondialdehyde (MDA) accumulation. Compared with QK, the soluble protein content, superoxide dismutase, peroxidase and catalase activities of RD in different periods were increased to varying degrees, while the MDA content was decreased, and there was no significant difference in pod yield. Our results suggested that RD could reduce the emergence time and the competition between plants, promote the growth of seedlings, accelerate the formation of seedling morphology, so as to establish a reasonable population structure, enhance the photosynthetic efficiency and dry matter production capacity of the population, effectively delay the aging process of the crop in the later stage, and finally increase pod yield.

Key words: peanut, single-seed seeding, directional seeding, cleaning stem base soil