AS型小麦雄性不育系研究初报

为了探求小麦新的不育类型,从普通小麦(T.aestivum L.)种内的一些品种和变种中,选取了10个具有不同特点的材料,以77(2)—1为共同亲本,进行了正反杂交和正反回交,并对其后代进行了考查。考查结果发现77(2)—1和印度矮生(T.sphaer-ococcum Perc.)的正反杂交后代和正反回交后代育性表现显著不同。当以77(2)—1做母本与印度矮生杂交时 F_1代表现为低不育,F_2代的育性发生分离,可育与不育的比例呈3:1。用印度矮生做父本与其 F_1代连续回交,则 BC_1、BC_2和 BC_3的后代全为不育株,从此便成为新的稳定的 AS 型小麦雄性不育系。由于新不育系是由栽培普通小麦的细胞质和印度矮生的核组配而成,故用此二变种名的第一个字母结合而命名为 AS 型。然而,反交结果大不相同。当以印度矮生做母本与77(2)—1杂交,F_1代表现育性正常,F_2代育性无分离,仍为全育。用77(2)—1做父本与其 F_1代连续回交,BC_1和 BC_2的后代也为全育。令人惊异的是:用反交 F_2代分离出来的性状与77(2)—1相似的可育单株,也能保持先正交、再回交后代中分离出来的全不育株,得到了全保持系。从上述初步结果可以看出:①栽培普通小麦种内某些品种或某些变种的细胞质存在着一定程度的分化,这种分化在特定的质核搭配组合中对育性能产生质的差异。②利用这种分化,为在普通小麦种内找到稳定的新不育质源以创造新型三系提供了可能。

A Preliminary Study of the AS-type Male Sterility of Wheat

In order to probe into a new male sterile type of wheat,10 different typal varieties with different characteristics in T.aestivum were selected to carry out the reciprocal cross and backcross with 77(2)-1 as the common parent plants.And at the same time,their progenies were also investigated.It was found from results investigated that their reciprocal cross and backcross progenies of 77(2)-1 and T.sphaerococcum showed significant difference in fertility.When 77(2)-1 used as female plant was crossed with T.sphaerococcum, F₁ plants appeared to be low sterile,but F₂ plants were segregated in proportion to 3:1 with respect to fertile and male sterile.When T.sphaerococcum used as male plant was backcross with F₁ plant,all the progenies of BC₁, BC₂ and BC₃ were completely male sterile.Thus,a new male sterile type with stable sterility,named "AS-type" male sterile was obtained.Since the new male sterile line was obtained from the combination of the cytoplasms of T.aestivum and T.sphaerococcum,the first letters of the two varieties have been used to give it new name "AS-type".And yet,results from backcross showed great difference.When T.sphaerococcum used as female plant was crossed with 77(2)-1,F₁ plants were normally fertile and F₂ plants were not segregated but completely fertile.When 77(2)-1 used as male plant was backcrossed with F₁ plant,all the progenies of BC₁ and BC₂ were also completely fertile.Notably,the complete male sterile plants segregated in backcross,when 77(2)-1 used as female was crossed with T.sphaerococcum,can be maintained steadily by the fertile plant in a similar way to 77(2)-1 segregated in F₂ ,when T.sphaerococcum used as female plant was crossed with male plant of 77(2)-1,a new male sterile type with stable sterility was obtained.It can be seen from the above results that:(1)there is probably a certain degree of differentiation of cytoplasm in some intraspecific varieties of T.aestivum,which under specific nuclear cytoplasm combination may produce a qualitative difference in fertility and (2) using the cytoplasmicva riability a new male sterile cytoplasm resources with stable sterility can be found,so as to provide the possibility for creation of new type lines.