Combining Ability and Classification of New Thirteen Yellow Maize Inbred Lines (Zea mays L.) Using Line X Tester Mating Design Across Three Locations

Thirteen new promising yellow maize inbred lines were top crossed with three inbred lines as testers, i.e., Sd.3, Sd.42 and Mallawy.5035 at Sids Agricultural Research Station during 2020 growing season. In the growing season 2021, the 39 top crosses and two yellow commercial check hybrids; SC.168 and SC.3444 were evaluated in a yield trail at three locations, i.e., Sids, Sakha and Nubaria Agricultural Research Stations. Data were recorded on days to 50% silking emergence (DTS day), plant height (PHT cm), ear height (EHT cm), ear position% (Epos%), percentage of plants to late wilt resistant (LWR%), grain yield plant^-1 (GYP^-1) and grain yield (GY ard fed^-1). Results showed significant differences between the three locations for all studied traits. Mean squares due to genotypes, crosses and their interaction with locations were significant for all studied traits except PHT, EHT and LWR% were not significant for C x Loc. Mean squares of lines, testers, line x tester and their interaction with locations were significant or highly significant for all studied traits except LWR% for T, L x Loc and T x Loc; DTS for T x Loc and PHT and EHT for L x T x Loc. Results showed that, L7 and L10 had good general combiner for DTS, PHT, EHT and Epos%  toward earliness, shorter plants, shorter ear heights and lower ear placement also L13 had the best combiner for highest GYP^-1, GY ard fed^-1 and resistant plants to late wilt disease. Eight crosses; L4 x T2, L5 x T2, L7 x T1, L8 x T1, L10 x T3, L12 x T3, L13 x T1 and L13 x T2 had positive and significant SCA effects for these traits. These crosses could be chosen for development of hybrids to be used by National Maize Breeding Program (NMBP). The results were showed that the thirteen inbred lines were placed into three heterotic groups; group1 and 2 consisted of four inbred lines in each group, while group 3 included three inbred lines. The method was not able to classify the three inbred lines; L3, L11 and L12 in any group. These results could be recommended for NMBP in selecting good parents for making hybrids and give breeder the chances for developing high yielding crosses through crossing of this inbred lines belonging to other inbred lines from different heterotic groups.