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一、当地食用品种护颖型和某些国外品种护颕型分别受一对基因所控制,杂种第一代以国外品种护颖型为显性(RR),当地食用品种护颖型为隐性(rr),第二代的现象型分离比例为3∶1,基因型为1 RR∶2 Rr∶1 rr;护颖型与着壳率之间为一因多效或密切连锁的遗传关系,凡 A 型护颕的植株或系统,着壳率均在10%以上,B 型护颖的植株或系统,均在5%左右;护颖型和千粒重之间存在着一定的连锁遗传关系,控制千粒重的多基因中,有一少部分与控制护颖的 R、r 基因相连锁,大部分基因则不受 R、r 基因的牵制,表现为独立分配。二、籽实着壳率的高低,对出米率有很大关系。一个优良品种除应具有高产、质佳等优良性状外,还必须具备着壳率低的特性。本文所列资料表明,当以 Kafir、Milo、Hegari与当地食用品种杂交选育优良品种时,只有选拔 B 型护颖的材料,才能育成着壳率低的品种。选拔 B 型护颖的材料在第二代即应开始。由于 B 型护颖为隐性,因此第二代的 B 型护颖株,以后世代即完全稳定,不再分离。第二代对表现为 A 型护颖、农艺性状相当优良的材料,也可当选,但第三代护颖型表现稳定时,则必须予以淘汰,若护颖型尚在分离,则应从中选择农艺性状优良的 B 型护颖植株。A 型与 B 型护颖的差别比较明显,特别是刚抽穗时,最易鉴别,因此在田间即可
First, the local varieties of food protection and some foreign varieties of protection are controlled by a pair of genes, respectively, the first generation of hybrids to foreign varieties of Ying Ying dominant (RR), the local varieties of Ying Ying recessive (rr). Phenotype separation ratio of the second generation was 3:1, and the genotype was 1 RR: 2 Rr:1 rr. The genetic relationship between genus and shell rate was due to multiple effects or close linkage, Where the type A guardrail plant or system, the shell rate of 10% or more, type B retaining Ying plants or systems, are about 5%; retaining Ying and 1000-grain weight there is a certain genetic relationship between the chain control A few of the 1000-grain weight polygenes are linked to the R and r genes that control the protection of the genus, and most of the genes are not restricted by the R and R genes and appear to be independently distributed. Second, the level of seed shell rate, a great relationship between the rate of rice. In addition to an excellent variety should have high yield, good quality and other fine traits, you must also have a low rate of shell characteristics. The information presented in this paper shows that when fine varieties are bred by crossing Kafir, Milo, Hegari and local edible varieties, only the materials of type B can be selected to breed the varieties with low shell percentage. Selection of B-type retaining Ying material in the second generation should begin. Since the B-type retaining Ying is recessive, so the second generation of B-type retaining Ying strains, after the generation that is completely stable, no longer separate. The second generation of the performance of the type A retaining Ying, agronomic traits quite good material, but also elected, but the third generation of Ying-type stable performance, you must be eliminated, if the retaining Ying-type is still separated, you should choose from B-type agronomic traits fine plants. A-type and B-type retaining Ying Ying obvious differences, especially when just heading, the most easy to identify, so in the field can