Effects of cut back at different leaf phenology stages on the growth of scion of rubber seedlings

Phenology can directly reflect the characteristics of rubber seedling, people can determine the agricultural time arrangements of seedling germination, cut back, tending management and nursery operation. In this study, the phenological period of the top leaf of hevea tree seedlings was divided into four treatments, and cut back was carried out in sprout period, bronze stage, light green stage and stable stage, respectively. The effects of sawing stock in different phenological periods on the budding rate and growth potential of scion 1-2 were observed. The results showed that the budding rate and nursery rate of scion were significantly higher than those of other stages when the leaf phenology stage was sawed in sprout stage and stable stage, and the budding rate and nursery rate were the lowest in the light green stage. In the first leaf whorl, the plant height of stock leaf phenology stage was significantly higher in sprout stage and bronze stage than in light green stage, but there was no significant difference with stable stage; The stem diameter of stable phenological stage was significantly larger than that of bronze and light green phenological stage, but there was no significant difference with that of sprout stage; The leaf whorl distance in the paleobronze period was significantly higher than that in the light green period, but there was no significant difference with other periods; The number of leaves in phenological stage was significantly more in sprout stage than in light green stage, and there was no significant difference from other stages. In the second leaf whorl, The plant height, stem diameter, leaf distance and leaf number of scion of stock seedlings in phenology stage were significantly higher than those in other stages, and the growth of stock seedlings in light green stage was lowest. In conclusion, the leaf phenology stage of the rootstock seedlings of rubber tree is in the sprout stage, and the scion growth is the best, followed by the stable stage and bronze stage. Cut back in the light green stage is not recommended.