果樹之幼年性與開花

On the Juvenility and Flowering of Fruit Trees

木木植物從種子發芽至個體衰老之過程中，呈現兩種不同現象，即絕對營養生長的幼年期與生殖、營養生長共存的成年期。果樹幼年期長短為當今果樹育種專家所關心之要事，本省早70在年代曾有論著探討此一問題。近年來對此方面之研究與探討為數甚多，故本文謹就果樹之幼年性，樹相之改變與縮短幼主期的方法加以闡述，提供果樹育種參考。

The duration of the juvenile phase of a fruit tree is primarily governed by genetic factors and secondly by environmental factors. In order to accelerate reproductive phase, precocious parents should be selected. The 'Indian-jujube' grown in Taiwan serves as the best example. For those genotypes which can not be efficiently manipulated by breeding methods, various cultural approaches are adopted to force seedling growth and shorten the juvenile phase. These include the application of fertilizers and artificial photoperiods. After the absolutejuvenile phase is over, the plants pass into 'transition stage.' They then are treated with methods such as grafting, ringing, bark inversion, pruning and application of growth regulators.