• 专家论述 •

### 再论杨允奎估算特殊配合力效应的简便方法

1. 四川农业大学 玉米研究所, 四川 雅安 625014
• 收稿日期:2005-12-14 出版日期:2006-06-30 发布日期:2017-03-06

### A Study on the Yang's Method of Estimating Special Combing Ability

WU Yuan-qi, PAN Guang-tang, RONG Ting-zhao

1. Maize Research Institute, Sichuan Agricultural University, Yaan 625014, Sichuan, China
• Received:2005-12-14 Online:2006-06-30 Published:2017-03-06

Abstract: Combing ability including the general combining ability(GCA) and the special combining ability(SCA), which was proposed by Sprague and Tatum(1942), can be expressed as the following statistical model, xij=μ+gi+gj+sij+eij. SCA is the difference between the observed value xij and the sum of μ+gi+gj if the error item eij were not thought about. Another method of estimating SCA, firstly proposed in a paper "A preliminary report on the study of quantitative traits in corn inbred lines" written by Prof. Yang Yunkui in 1965, is defined as the difference between xij and the mean parents value(MP), viz. s'ij=xij-(1)/(2)(xi.+x.j)=sij+(1)/(2)(gi+gj). The two methods of estimating SCA differs from each other because the origins denote differently. GCA was enlarged and SCA was dwindled as the genetic hypothesis of Sprague's definition of combining ability and the origin were improper, and the hybrid superiority was expressed truly. On the other hand, the Yang's definition of SCA, which was consistent to hybrid superiority, possessed unambiguous foundation of genetic theory. Moreover, the most used method of calculating GCA and SCA is the one proposed by Griffing(1956) which adopted the least squares. By using the theories and methods of quantitative genetics, three methods and their relationship were analyzed and compared to understand the different results from method 3 and 4 of Griffing's diallel cross trials. To these trails, the results of GCA and SCA may be inter-transformed and inter-validated among three methods. If the object is evaluating the value of a series parents, three methods can yield the same conclusion. Otherwise, if forecasting hybrid superiority is the mainly object, the Yang's method of estimating SCA can be the most reliable.

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