Moreno-Gonzalez J
Centro de Investigaciones Agrarias de Mabegondo, La Coruña, Spain.
Genetics. 1993 Sep;135(1):223-31. doi: 10.1093/genetics/135.1.223.
Knowledge about the efficiency of generations for estimating marker-associated QTLs is needed for selection. The objective of this paper is to develop a theory to compare the efficiency of segregating generations and testcrosses from the cross of two inbred lines differing in value for a quantitative trait (P1 x P2) for estimating additive, dominance and heterotic effects of QTLs by stepwise regression. An equation that predicts the smallest gene effect in genetic standard deviation units that can be detected with 50% chance at a significance level as a function of the heritability (h2) and the recombination frequency (r) of markers was developed for the segregating generations and testcrosses. For estimating additive effects, the most efficient generation was the doubled-haploid (DH) lines; the most inefficient was the North Carolina Design III (NCD III), followed by selfed backcrosses (SB); the selfed families from F2 individual plants (F2:3 lines) are inferior to the recombinant inbreds (RI) for low r, but are better than RI for high h2 and r. Dominance effects are less efficiently estimated than additive effects. The NCD III is better than the SB and the F2:3 lines for detecting dominance effects. The RI and DH do not estimate dominance effects. The differential heterotic QTL effects of lines P1 and P2 when crossed with tester T can be estimated by evaluating testcrosses of individual F2 plants (F2T), recombinant inbreds (RIT) and double-haploid lines (DHT). The DHT is superior to the other generations. The F2T is better than the RIT for r > or = 0.20, but inferior for r < or = 0.1 or low heritability.
选择时需要了解世代对于估计标记相关QTL的效率。本文的目的是建立一种理论，用于比较两个自交系杂交（P1×P2）中，用于通过逐步回归估计QTL加性、显性和杂种优势效应的分离世代和测交的效率。针对分离世代和测交，开发了一个方程，该方程可预测在显著水平下，以50%概率能够检测到的、以遗传标准差单位表示的最小基因效应，该效应是遗传力（h2）和标记重组频率（r）的函数。对于估计加性效应，最有效的世代是加倍单倍体（DH）系；最无效的是北卡罗来纳设计III（NCD III），其次是自交回交（SB）；来自F2单株的自交家系（F2:3系）在r较低时不如重组自交系（RI），但在h2和r较高时优于RI。显性效应的估计效率低于加性效应。NCD III在检测显性效应方面优于SB和F2:3系。RI和DH无法估计显性效应。通过评估单个F2植株（F2T）、重组自交系（RIT）和加倍单倍体系（DHT）的测交，可以估计系P1和P2与测验种T杂交时的差异杂种优势QTL效应。DHT优于其他世代。当r≥0.20时，F2T优于RIT，但当r≤0.1或遗传力较低时则不如RIT。
