English

Abstract

Wheat (Triticum aestivum L.) is a major food crop in Pakistan and of the world as well. During 2013-14, Pakistan produced 25.98 million tons wheat from 9.19 million hectares with an average yield of 2824 kg ha (MINNFSAR, 2015). However, geometrical increase in Pakistan population has been a challenge for agricultural scientists. To feed increasing population of Pakistan, there is a dire need to develop wheat genotypes with high yield potential. This could be achieved by combining together good attributes from available wheat germplasm into a single genotype (Khan et al., 2014). Assessment of general combining ability (GCA) effects for yield components has great potential in selection of desirable parents (Bhateria et al., 2006). Highly productive wheat cultivars could be developed by crossing good general combining genotypes for grain yield and its components and selecting desirable segregants from resulting hybrid populations. Line × tester analysis is an evaluation technique, developed by Kempthrone (1957), which is a modified form of top cross scheme. In case of top cross only one tester is used, while in line × tester mating several testers are used. The first step in evaluating the potential of new lines is to cross them to a common parent (tester) and compare the performance of their hybrids (test crosses or top crosses). Knowledge of general and specific combining abilities influencing yield and its components has become increasingly important to the plant breeders in order to select suitable parents for developing potential hybrids (Kruvadi, 1991). Many researchers have studied the combining ability and genetic structure of bread wheat hybrid populations using line × tester method related to yield and yield components. It is reported that grain yield plant and most of traits are under control of non-additive gene effect (Sulayman and Akguni, 2007). Several researchers (Larik et al., 1995; Akbar et al., 1997; Masood and Kronstad, 2000; Ahmadi et al., 2003; Joshi et al., 2003) have reported that majority of genetic variances of grain yield as well as yield components are under control of non-additive nature of genes. However, Akbar et al. (1997) have reported that numbers of tillers plant is controlled by additive gene action. This study was undertaken to find out good general combining lines and testers for important yield contributing traits, so that superior cross combination are selected for development of desirable wheat genotypes. Pak. J. Agri. Sci., Vol. 53(3), xxx-xxx; 2016 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 DOI:10.21162/PAKJAS/16.2036 http://www.pakjas.com.pk