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甜菜是常异交作物,其天然杂交率在60％左右,故甜菜是一个遗传基础较复杂的群体,后代性状分离十分严重,优良性状不能稳定遗传,杂种优势不能保持,所以用一个杂合体甜菜作杂交制种亲本,不能取得良好效果。但是使用纯度高,一般配合力及特殊配合力好的自交系或自交系的单交种、三交种或双交种作杂交制种的亲本,则能选育出杂交优势强、抗病性好的优良品种用于生产。选育自交系的目的,就是通过多代人工强制自交的手段把一个复杂的甜菜群体分解出各具特性的许多个纯系,经过一般配合力和特殊配合力测定试验,淘汰不良系号,选择优良系号用于杂交亲本。
Beets are often outcrossed crops, the natural hybridization rate of about 60%, so beet is a more complex genetic groups, the offspring traits separation is very serious, excellent traits can not be stable inheritance, heterosis can not be maintained, so with a hybrid beet For hybrid seed production, can not achieve good results. However, the use of high purity, general combining ability and special combining ability good inbred lines or inbred lines of single, three or double crosses for hybrid seed production, you can bred hybrids strong, resistant Good disease good varieties for production. The purpose of breeding inbred lines is to decompose a complex beet population into many pure lines with different characteristics by means of artificial forcings for many generations. Through the general combining ability and special combining ability test, the bad lines , Choose a good system for hybrid parents.