Abstract:

In order to explore the suitable pruning parameters for Ziziphus jujuba‘Huizao’under the central leader tree shaped cultivation mode，a four-factor quadratic mathematical model was established with plant height，main branch number，secondary branch number per main branch，and jujube stock number per secondary branch as variable factors and plant yield and fruit rate above grade one（including grade one fruit）as objective functions，using a mixed-level uniform design. The“continuous mathematical model simulation + normalization processing + clustering”was used for model joint optimization to obtain the best high-yield and high-quality tree-shaped parameters. Model analysis shows that plant height，main branch number，secondary branch number per main branch，and jujube stock number per secondary branch all have significant effects on plant yield and fruit rate above grade one for Ziziphus jujuba‘Huizao’. Computer simulation shows that under the central leader tree shaped cultivation mode with a plant row spacing of 1.0 m × 4.5 m，the highest plant yield Y_y = 4.6453 kg （fruit rate above grade one Y_g = 10.7729%）is obtained when the plant height is 2.7 m，the main branch number is eleven，the secondary branch number per main branch is eight，and the jujube stock number per secondary branch is ten. The highest fruit rate above grade one Y_g = 36.7964%（plant yield Y_y = 3.9255 kg）is obtained when the plant height is 3.0 m，the main branch number is seven，the secondary branch number per main branch is four，and the jujube stock number per secondary branch is six. Through joint optimization，the combination of plant height 2.8 m，main branch number seven，secondary branch number per main branch six，and jujube stock number per secondary branch nine is the high-yield and high-quality combination for Ziziphus jujuba‘Huizao’with a plant yield of 4.12 kg and a fruit rate above grade one of 28.57%.

Key words: Ziziphus jujuba, central leader shape, tree shape, high quality, high yield, parameter, modeling