改良S_1选择法对12个玉米群体改良效果的比较分析

为了对玉米群体进行合理有效的改良利用,通过改良S1选择法对12个玉米群体改良一轮后进行效果比较分析。结果表明,穗行数、行粒数和百粒重是构成产量的三因素,遗传增益最大的群体为蒙群2,其他依次为蒙群4、蒙群1等7个群体,蒙群3及3个国外引进群体遗传增益为负值;玉米群体在穗部、植株性状以及遗传变异中均存在一定的变化。试验研究得出,蒙群2、蒙群4、中综7号、蒙C群、蒙A群产量遗传增益均较大,并在其他农艺性状中改良效果显著,可直接选择优株自交进行选系,而其余7个群体遗传增益小,改良利用潜力不大。

玉米龙早群S_1后代轮回选择效果的研究

用S_1后代轮回选择法对北方早熟春玉米群体——龙早群进行了二轮轮回选择。结果表明,C_1比C_0提高5％以上遗传进度的性状有产量、株高、穗位高和百粒重等性状,抽丝日数、穗长、穗行数、行粒数、穗粗等性状的遗传进度均不足5％,丝黑穗病本轮选择后下降1.8％,抗大斑病有所增加。二轮选择优选株比较发现,单株籽粒产量、粒行数、行粒教、穗长等C_1较C_2遗传进展明显。

Comparative Analysis of Improving Effects of 12 Maize Populations with Improved S_1 Selection Method

ln this study, 12 maize populations were improved with the improved S1 selection method, aiming to increase the improvement efficiency of maize popula-tions. The results showed that number of rows per spike, number of grains per row and 100-grain weight were the three important component traits of maize yield. The highest genetic increment was found in Mengqun 2, fol owed by Mengqun 4, Mengqun 1 and other 7 maize populations. Negative genetic increment was shown in Mengqun 3 and 3 introduced foreign maize populations. Some changes were shown in spikes, plant traits and genetic diversity of maize populations. Based on our results, we concluded that Mengqun 2, Mengqun 4, Zhongzong 7, Mengqun C and Mengqun A could be directly used for the line breeding by selfing for their higher genetic increment of yield and better improvement effects of other agricultural traits. Compared with these 5 populations, the improvement potential of other maize populations was limited for their lower genetic increment.

S_1选择法对玉米群体产量性状改良效果的比较分析

以产量性状及农艺性状作为研究对象,比较分析前人利用S1选择法实施群体改良获得的遗传增益、遗传变异及对玉米群体结构的影响。比较发现,S1选择法能够有效提高玉米群体产量和一般配合力,降低群体茎秆倒伏率和子粒含水量,但遗传方差降低较快。育种可考虑先运用混合选择法改良群体,克服遗传方差迅速降低的缺点,然后进行2～3轮的S1选择法进一步提高产量、适应性及耐自交能力,进而创造优异的育种新材料。