The shading caused by maize inhibited the growth of soybean, reduced the yield of soybean under maize–soybean relay strip intercropping system. To investigate whether foliar spraying different types of plant growth regulators could improve the growth and yield of intercropped soybean. We conducted a sequential field experiment in 2018 and 2019, with foliar spraying of uniconazole (S3307), 6-benzyladenine (6-BA), diethyl aminoethyl hexanoate (DA-6) and water (CK) on soybean at the anthesis stage. Results showed the value of leaf area index, and chlorophyll (a + b) content, and net photosynthesis rat of soybean leaves were highest under DA-6 and significantly higher than CK at 56 day after spraying (DAS). Foliar spraying 6-BA, S3307 and DA-6 increased the activities of superoxide dismutase (SOD), peroxide (POD), and catalase (CAT) of soybean leaves at 35 and 56 DAS. The soybean aboveground dry matter weight and the dry matter accumulation after flowering stage was highest under DA-6 treatment, and the dry matter transportation ratio and the proportion of dry matter in pods were highest under S3307 treatment. The value of maximum grain filling rate (Vmax) and mean grain filling rate (Vmean) of soybean were highest in S3307, while the value of active grain filling period (D) was highest in DA-6. The hundred-grains weight was highest in S3307, then followed by DA-6 and S3307. The pods per plant in DA-6 were significantly higher than in 6-BA and S3307 and increased by 25.4% and 32.9% compared to CK in 2018 and 2019, respectively. Foliar spraying DA-6 (60 mg L−1) has a better effect on increasing the physiological function and photosynthetic capacity of leaves, leading to improving the grain filling process and increasing the yield of relay-intercropped soybean.

中文翻译：

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Uniconazole、6-Benzyladenine 和二乙基氨基乙基己酸酯通过提高光合效率和增加玉米 - 大豆中转条带间作系统中的籽粒饱满度来增加大豆产量

玉米遮荫抑制了大豆的生长，降低了玉米-大豆轮作条带间作制度下大豆的产量。研究叶面喷施不同类型植物生长调节剂是否能提高间作大豆的生长和产量。我们在 2018 年和 2019 年进行了连续田间试验，在开花期对大豆进行了叶面喷施咪唑 (S3307)、6-苄基腺嘌呤 (6-BA)、氨基乙基己酸 (DA-6) 和水 (CK)。结果表明，DA-6处理下大豆叶片叶面积指数值、叶绿素(a+b)含量和净光合大鼠最高，喷后56天(DAS)显着高于CK。叶面喷施 6-BA、S3307 和 DA-6 增加了超氧化物歧化酶 (SOD)、过氧化物 (POD)、35 和 56 DAS 时大豆叶片的过氧化氢酶 (CAT)。DA-6处理的大豆地上干物质质量和开花期后干物质积累量最高，S3307处理的干物质运输率和豆荚干物质比例最高。大豆最大灌浆率(Vmax)和平均灌浆率(Vmean)以S3307最高，而活跃灌浆期(D)以DA-6最高。百粒重最高的是S3307，其次是DA-6和S3307。DA-6 的单株荚数显着高于 6-BA 和 S3307，与 CK 相比，2018 年和 2019 年分别增加了 25.4% 和 32.9%。