Evaluation of New Yellow Inbred Lines of Maize in Their Testcross for Ear Position and Grain Yield

Abstract

General and specific combining ability were estimated for different traits in a lines x testers crossing program comprising 36 top crosses produced by crossing eighteen yellow inbred lines with two testers; i.e., inbred line Sk-11 and promising single cross Sk136 (commercial name S.C177, 2013) in 2012 season. The resulting 36 test crosses along with two check hybrids, i.e. SC.168 and TWC353 were evaluated at Sakha and Sids Agric. Res. Stations in 2013 growing season. Significant and highly significant mean squares were found due to locations and hybrids for all traits, also the interaction between locations x hybrids was significant and highly significant for grain yield and ear position, respectively. Mean squares due to lines (L) and testers (T) and their interaction were significant and highly significant for all the studied traits, except testers for grain yield and L x T for ear diameter. The additive gene action was more important than nonadditive gene action for all the studied traits, except ear length and grain yield, while, the non-additive gene action was the most sensitive to environmental conditions than additive gene action for all traits except ear length. The best parental inbred lines which revealed desirable GCA effects were Sk-6054/61 for days to 50% silking and plant height, Sk-6036/58 and Sk-6043/60 for ear position, Sk6061/63 and Sk6061/64 for ear length, Sk-521 for ear diameter and Sk-6035/57 and Sk-6061/63 for grain yield. Whereas, the tester SC Sk-136 was the best combiner for all studied traits except days to 50% silking and plant height. Five crosses, i.e., Sk-5002/47 x SC-Sk-136, Sk-6043/60 x Sk-11, Sk6061/3 x Sk-11, Sk-6061/64 x Sk-11and Sk-521 x Sk136 showed the best specific combining ability effects for grain yield. The best hybrids that showed useful heterosis for both ear position and grain yield were Sk-6035/57 x Sk-11, 6035/57 x SC Sk-136 and Sk-521 x Sc sk136. Two single crosses, i.e.; Sk-6035/57 x Sk-11 (37.03 ard fed -1 ) and Sk6061/63 x Sk-11 (37.25 ard fed -1 ) were significantly superior and outyielded check hybrid SC168 (33.50 ± 2.95) and fourteen three-way crosses were significantly superior and out yielded check hybrid TWC 353 (26.37 ± 2.95 ard. fed -1 ) These single and three crosses