Combining Ability and Heterosis for Some Agro-Morphological Traits in Potato (Solanum tuberosum L.) Using Line × Tester Mating Design

The nature and magnitude of gene action is an important factor in developing an effective breeding program. Combining ability analysis is useful in assessing the potential inbred lines and helps in identifying the nature of gene action involved in various quantitative characteristics. This information is helpful to plant breeders for formulating hybrid breeding programs. Therefore, the objectives of the present research were to determine combining ability, heritability and heterosis of tuber yield and some agronomic traits in potato using line × tester mating design. In order to determine combining ability, heritability and heterosis of tuber yield and some agronomic traits in potato, three lines were crossed with two testers. Parents and their F1 progenies were arranged in randomized complete block design with three replications using line × tester (3 × 2) mating design. Analysis of variance showed significant differences among genotypes for all traits; thus line × tester analysis was performed. Among the lines, line L1 (Caeser) had significant positive GCA for tuber yield, tuber weight per plant, tuber number per plant, main stem number and plant height. Among the testers, tester T1 (Luca) showed significant positive GCA for tuber yield, tuber weight per plant, tuber number per plant and tuber dry matter. Among the hybrids, the hybrids (Satina × Luca) (T1 × L3) and (Caeser × Savalan) (T2 × L1) showed significant positive SCA effects for tuber yield, tuber weight per plant and tuber number per plant. The SCA variance was higher in magnitude than the GCA variance for all the characteristics and baker coefficient indicated the predominance of non-additive type of gene action for the expression of these characteristics. High general heritability and relatively low specific heritability were observed for all traits. Hybrid (Satina × Luca) had the highest heterosis for tuber yield. The importance of additive and non-additive genetic effects is well established in controlling many traits in potato. It was shown that the dominance effects of the genes played a major role in the variation of tuber yield in potato. Based on the results of the current study the SCA variance was higher in magnitude than the GCA variance for all the characteristics and baker coefficient indicated the predominance of non-additive type of gene action for the expression of these characteristics. Heterosis and combining ability is prerequisite for developing a good hybrid variety of potato. According to this research, the (Satina × Luca) cross had the highest heterosis for tuber yield and was recommended as the most promising combination for developing high yielding hybrid potato genotypes.