玉米杂种优势类群和模式的研究　Ⅰ玉米国外血缘杂优类群数量性状的遗传分析

Genetic Analysis of the Quantitative Traits for Maize Heterosis Population Abstracted from the Exotic Germplasms

采用ＮＣⅡ交配设计，研究分析了我国具有国外血缘杂种优势群优良玉米自交系的基本遗传参数及其与国内血缘自交系之间的关系。结果表明，在这一优势群的优良自交系中，多数数量性状遗传变异较大，具有进一步改良提高的潜力。单株产量、行粒数、株高、穗行数的显性方差大于加性方差，其余性状的显性方差小于或等于加性方差；国内血缘自交系与之杂交，单株产量的一般配合力较高，说明二者的基因型间普遍存在着较大的遗传差异。因此，应根据＂国内系×国外系＂杂优利用的原则，在具有国外血缘杂种优势群中，通过回交、二环系法和轮回选择等途径，对自交系加以改良利用。并讨论了杂种优势类群和模式的建立。

The estimates of the genetic parameters for 13 quantitative traits of the excellent maize inbred lines abstracted from the exotic germplasms and the analysis of the relationship between the lines from exotic germplasms and the lines from domestic germplasms were made based on NC Ⅱdesign. There was large genetic variance for most traits investigated in the lines from the exotic heterosis population. Dominant variances were found greater than additive variances for grain yield per plant, kernels per row, plant height, rows per ear while dominant variances than additive variances for the rest traits. Domestic lines showed high g. c. a. effects in the genetic background of the exotic lines. Based on the principle of exotic line ×domestic line, the excellent exotic lines will be efficiently improved by means of backcross, second cycle and recurrent selection after crossing was made between the lines from the same exotic heterosis population.