核桃、板栗、苹果等果树中的大部分品种,自花结实率很低,即大都要经异花授粉才能结实。因而,核桃、板栗、苹果的种子,实际上皆为天然杂交种。在用种子繁殖果树时,实生的后代与其母本(或父本)比较;有明显的分离——变异现象,在果树上通称为实生变异。为了保持果树品种的优良性状,苹果、梨等果树,都采用嫁接即营养繁 Most varieties of walnuts, chestnuts, apples and other fruit trees, self-infested rate is very low, that is, mostly by cross-pollination in order to be strong. Thus, walnuts, chestnuts, apples, seeds, are actually all natural hybrids. In the breeding of fruit trees with seed, the actual offspring and their parents (or paternal) comparison; obvious separation - mutation phenomenon, known as the fruit tree in the real mutation. In order to maintain the fine traits of fruit trees, apples, pears and other fruit trees, are grafted nutrition