平衡式疏果修剪法对龙眼生长与结果的影响

为探明幼果期疏果结合修剪对龙眼植株生长和结果的影响，选用6 年生‘石硖’幼年结果树为试材，以回缩修剪、初始结果枝率、初始单穗果数为试验因素，采用L9(34)正交设计，研究不同试验因素对果实成熟时的新梢比率、落果速率、结果枝率、单穗果数、产量、成熟期和果实品质的影响，并初步筛选出优势因素与水平组合。结果表明：经过疏果修剪的各处理植株在枝梢生长、果实发育和成熟品质上，都与对照有着明显差异，表现为落果率降低(P<0.01)，成熟期提前，有一定的新梢比率，且合适的处理有助于提高植株单位产量；单果重增加，果肉TSS含量提高，果色偏向干净、明艳的黄绿色(P<0.01)。初始结果枝率越高的处理，成熟时果枝比率越高；回缩修剪植株的果实外观色泽比不修剪的偏向饱和黄绿色；初始单穗果数越高的处理，果实发育越慢、落果速率越高、成熟时单穗果数越多、成熟期也越晚；单穗果数处于中间水平60 粒的处理，单果重和TSS含量最高(P<0.01)。正交试验方差分析结果显示，成熟时单穗果数在因素初始单穗果数、果表h°值在因素矮化修剪的不同水平上存在显著差异(P<0.05)；直观分析结果显示，结果枝率50%~60%、单穗果数60 粒左右，适度的回缩修剪，是龙眼植株获取生长与结果、产量与品质平衡关系的最优组合。该技术为生产应用提供了可行的操作指导。

Effects of Balanced Pruning Combined with Young Fruit Thinning on the Growth and Fruiting of Longan Trees

This paper aims to study the effects of young fruit thinning combined with pruning on the growth and fruiting of longan trees. Twelve 6-year-old fruiting trees of longan‘Shixia’were used as materials, and a L9(34) orthogonal design was adopted to test the effects of different factors, including retractive pruning, initial rate offruiting branches and initial number of fruit per panicle, on shoot ratio, fruit dropping rate, fruiting branch rate, the number of fruits per panicle, yield, mature period and fruit quality when fruit ripening, and the combination of advantageous factors and levels was also screened. The research results showed that there were remarkabledifferences between the treatments and control in shoot growth, fruit development and mature quality (P<0.01), along with the specific performance as follows: the decreased fruit drop rate (P<0.01), earlier maturity, a certain ratio of new shoots, improved unit yield, increased fruit weight and TSS content, and cleaner brightyellow green for fruit color (P<0.01). Higher initial rate of fruiting branches were among the treatments, higher rate of those when ripening, and the fruit color of the trees with retractive pruning treatment tended to be saturated yellow green. The more the initial fruit amount per panicle, the more slowly the fruit development, thehigher the fruit dripping speed, the later the fruit ripening and the higher number the fruit per panicle. Furthermore, the single fruit mass and TSS content of aril were all the highest, which matured on the trees with treatment at a middle level of initial fruit amount of 60 per panicle. The variance analysis of the orthogonal test showed that there were significant differences (P<0.05) between the levels of the factor initial number of fruit per panicle in the number of ripening fruit per panicle and the factor retractive pruning in the h° value, and the results of visual analysis showed that the optimal combination to obtain the balance between the growth and fruiting of longan trees as well as the yield and quality of longan fruits was: fruiting branches of 50%-60%, about 60 fruits per panicle and reasonable retractive pruning. Therefore, this study can provide a feasible instruction for longan production.