玉米群体改良的改良S_1综合选择法

玉米群体改良的方法很多,但均有不足。60年代人们提出了S_1选择法,因其克服了混合选择法和测交选择法的主要缺点,故得到普遍关注和广泛应用。但这个方法具有选择周期长(三季一轮),遗传方差下降快的缺点。1988年我们提出了改良S_1综合选择法(MS_1)。此后B.S.Dhillon(1989)亦提出了与之类似的改良S_1选择法。MS_1选择法缩短了选择周期,改S_1选择法三季一轮为二季一轮,同时克服了S_1选择法遗传方差下降过快的缺点。MS_1选择法可以和半同胞(HS)选择法交替进行。通过比较,MS_1选择法、MS_1—HS交替选择法可望比其它群体内改良方法获得更大的遗传进展。MS_1选择法还可与半同胞(HS)选择法联合进行,简称MS_1—HS联合鉴定法。此法比Lonnquist(1967)提出的HS—S_1联合鉴定法有更大的优越性。

Modified Method of S1 Combined Recurrent Selection in Maize Improvement.

There are many selection methods of maize(zea mays L.) population improvement, but all with some defects. Therefor, the S1 recurrent selection method, which has surmounted the main shortcomings of mass selection and tested selection method, was proposed in 60s, and was paid greatly attention and widely used. Long selection period and genetic variance rapid reduction are the main problems in this method. Therefor, we proposed a modified method of S1 combined recurrent selection(MS1) in 1988. In the modified method, two growing seasons are enough, while three growing seasons are usually needed for one cycle of S1. The modified method can also surmount genetic variance rapid reduction. Under certain situation, one cycle of modified S1 selection alternated with one cycle of half—sib selection can be completed in two seasons. Genetic gains from both the modified S1 selection and modified S1 selection alternated with half—sib selection methods were expected to be greater than those from other methods, If modified S1 selection method combined with half—sib selection, it was expected to be better than half—sib selection and S1 combined selection(lonquist, 1967). It can shorten selection period and not need selecting in prolific ears population.