顶端优势,是指同一枝条上部的芽、枝生长势力强,向下依次减弱的现象,也可叫做极性。顶端优势强弱,受品种、树龄、枝条着生部位及着生姿势等因子的影响.品种间,青香蕉、国光的顶端优势强于红玉;幼、旺树强于老弱树;直立枝强于斜垂枝。生产实践中,可利用果树顶端优势的特性整形修剪。为扩大树冠,加快整形,可选壮枝,壮芽带头,使枝条生长加速,粗壮有力。为改变树体的上强下弱现象,中央领导干可选弱枝、弱芽带头,或采取弯曲上升,改变直立状态,以削弱顶端优势.为均衡同一层主枝间的生长势力,强壮的主枝可选角度大、势力弱的枝带头,弱枝则可适当抬高角度。背上的直立旺枝,可采用改变方向等手法,使其水平或斜垂生长,抑制其顶端优势,很快就会成花结果。角度不开张的幼树,常显得顶端优势强,直条多呈直立生长。如采 Top edge, refers to the same branches of the shoots, branches grow strong, down the order of the phenomenon weakened, also called polarity. The top superiority is affected by the variety, age, the location of the branches and the posturing posture, etc. Among the cultivars, the top superiority of green banana and Guoguang is stronger than that of red jade; young and wang trees are stronger than the old and weak trees; Stronger than oblique weeping sticks. Production practice, you can use the top edge of the characteristics of fruit plastic trim. To expand the crown, accelerate the shaping, optional Zhuangzhi, Zhuangma take the lead to accelerate the growth of branches, thick and powerful. In order to change the weakness of the tree, the central leadership can choose weak branches, weak sprouts take the lead, or take a curved rise, change the upright state, in order to weaken the top edge .In order to balance the growth forces between the same main branch, strong The main branch of the angle of choice, weak branches take the lead, weak branches can be properly raised angle. Upright Wang branches back, you can change the direction of such practices, so that its horizontal or oblique growth, inhibiting the top edge, will soon become a flower result. Sapling not open angle, often appear to be the top edge of the strong, mostly upright straight growth. Mining