Effect of thinning flower buds on fruit and seed traits and root yield of Panax ginseng C.A. Meyer

Panax ginseng C.A. Meyer, commonly known as ginseng, is a perennial herb. Agricultural practices have an influence on growth and yield of P. ginseng plants. Effect of thinning flower buds (treatment A (TA) the outermost whorl of flower buds in the umbels was retained while all other buds were excised; treatment B (TB) the two outer whorls of flower buds in the umbels) on fruit traits, which include number of fruits per plant, single fruit: double fruit ratio, fruit weigh (FW) per square meter, weight of 100 fruits, vertical length of fruit (VLF), horizontal diameter of the fruit (HFD) and thickness of the fruit (TF), seed traits, which include number of seeds per square meter, weight of 1000 seeds, number of different seed grading categories (extremely large seeds (ELS), large seeds (LS), medium-sized seeds (MS), small seeds (SS)) per square meter, vertical length of the seed (VLS), horizontal diameter of the seed (HSD), thickness of the seed (TS), and the root yield and total ginsenosides content of root of four- and five-year-old cultivated P. ginseng was studied in Fusong region of north-eastern China. The results showed that the FW and VLF, the weight of 1000 seeds, number of ELS per square meter, VLS and HDS of ELS, HDS and TS of MS and root yield were increased significantly by TA and TB (p<0.05), whereas the number of MS and SS were significantly reduced (p<0.05) in four- and five-year-old plants. The number of ELS and LS in TB and control were higher than that of in TA, and not significant was observed between TB and control. The root yield in TB was significantly higher than that in control of five-year-old plants. Number of the seeds per square meter of five-year-old plants was higher than that of four-year-old plants. The results indicated that the method of thinning flower buds, which was the two outer whorls of flower buds in the umbels, on five-year-old cultivated P. ginseng plants was a favourable method to promote the production of high-quality seeds and maximise the root yield.