一、问题的提出采用回交的方法可以达到细胞核置换的目的.因此,在作物育种中,进行抗性育种、培育不育系及核质杂种等都广泛采用回交的方法.木原均(1977)报道:以节节麦(Aegi-lops squarrosa)为母本与普通小麦Gaines杂交,再以Gaines回交,所获得的核质杂种,产量比Gaines原种高,成熟期提早,蛋白质含量也提高.Sauche-monge(1973)报道:采用核置换回交的方法,引入外来的细胞质后,使8个感染秆锈病21号及133号生理小种的小麦品种变为抗病.Meredith(1977)报道:用岱字棉16号(高产品种)为轮回亲本,通过回交的方法选育出纤维强度大又高产的棉 First, the problem raised by the method of backcross can achieve the purpose of nuclear replacement.Therefore, in crop breeding, resistance breeding, breeding of sterile lines and hybrids are widely used nuclear backcross method. ) Reported that Aegilops sinensis hybridized with common wheat Gaines and Gaines backcrossed, the yield of hybrids was higher than that of Gaines, with an earlier maturity and higher protein content .Sauche-monge (1973) reported that using nuclear replacement backcrossing methods, introduction of extraneous cytoplasm turned eight wheat cultivars infected with stem rust Nos. 21 and 133 into disease resistance. : With Dai word cotton 16 (high-yield varieties) as the reincarnated parents, by backcross breeding methods of fiber strength and high yield of cotton