Abstract:

The effects of various foliar sprays on Chinese milk vetch （Astragalus sinicus cv. Xinzi-1） seed number and seed weight at the squaring stage were studied in order to provide reference information for improving yield through use of chemical regulators. Foliar spraying of paclobutrazol （PP₃₃₃）， 6-benzylaminopurine （6-BA）， brassinolide （BR）， alginate oligosaccharides （AOS） and compound nutrition preparation （NCD） were performed at the squaring stage， while spraying water as the control. At the flowering and harvest stages， the seed setting was investigated for inflorescences at the basal， central， and apical inflorescence positions on the main stem. It was found that， compared with the water control， the various spray treatments improved the pod and seed setting rates in the examined inflorescence positions at flowering， and improved the seed number and seed weight in those inflorescence positions at harvest. NCD was the best treatment； the seed number at the basal， central and apical inflorescence positions was increased by 27.79%， 29.35% and 71.25%， respectively， and the seed weight at the same positions was increased by 27.18%， 28.65% and 71.05%， respectively， compared with the control. The seed yields under NCD， PP₃₃₃， BR， 6-BA and AOS treatments were significantly higher than those of the control， with increases of 29.73%， 22.02%， 19.02%， 10.52% and 10.01%， respectively. The seed yield under NCD treatment was the highest， and was 601.37 kg·ha^-1. Among the treatments， PP₃₃₃ and 6-BA treatments induced significant increases in seed number， but no obvious effect on seed weight， while the BR and AOS treatments induced significant increases in seed weight， but not seed number. The NCD treatment induced significant effects both on seed number and seed weight. In summary， foliar spray of plant regulators at squaring stage significantly promoted increased seed yield and the NCD treatment has the greatest effect， followed by PP₃₃₃， BR， 6-BA and AOS.

Key words: Chinese milk vetch, foliar spray, seed number, seed weight, yield