No abstract

Ten yellow maize inbred lines and three testers were top crossed in line × tester scheme in 2019 season. The resulted 30 top crosses with two check hybrids were evaluated at two locations in 2020 growing season to assess mean performance, general and specific combining ability and their interaction with locations as well as elucidate type of gene action. The recorded data were days to 50% silking, plant height, ear height, ear length, ear diameter, No. of rows/ear, No. of kernels/row and grain yield (ardab/fed). The results showed that, the mean squares due to locations (Loc), genotypes (G), crosses (Cr.), G × Loc and Cr. × Loc interactions were significant for all the studied traits. Highly significant differences were observed among the evaluated lines (L), testers (T) and its corresponding hybrids for all traits. non-additive gene action gave an important role in the inheritance of all the studied traits. The inbred lines L2, L4 and L6 showed the best desirable GCA effects for earliness, L6, L7 and L10 for shortness and L4, L5, L6, L7 and L9 for lower ear placement. Whereas the inbreeds L3, L6 and L7 were the best general combiners for grain yield. The crosses L2×T1, L8×T1, L1×T2, L7×T2, L3×T3, L6×T3 and L10×T3 had the best SCA effects for grain yield. The ten inbred lines were classified into three different heterotic groups using HSGCA method. These groups could be used for selecting the best parents for making crosses in maize breeding programs.

No abstract

Egyptian Journal of Agronomy http://agro.journals.ekb.eg/ 11 M AIZE (Zea mays L.) is the third-most significant cereal grain in Egypt, although it is susceptible to water stress, which results in substantial losses in both productivity and quality. A set of 100 S1-lines along with their top-crosses using two testers were evaluated under normal and water stress conditions. We used line × tester to evaluate general (GCA) and specific (SCA) combining ability effects for Days to 50% anthesis, Days to 50% silking, and Anthesis silking interval. Results of line × tester analysis showed highly significant differences among parents, crosses vs parents under normal and water stress condition. Both lines and testers showed significant and non-significant differences. Finally, line × tester analysis showed significant differences for Days to 50% anthesis and non-significant differences for Days to 50% silking under normal and water stress condition while, anthesis silking interval trait showed non-significant differences under normal condition and significant differences under water stress condition. Broad sense heritability values for the aforementioned traits were higher under water stress compared to those under normal condition. The high values of broad sense heritability make the selection process easier for the plant breeder and more accurate as the phenotype reflects its genotype. Our findings suggested that dominance genes predominately regulate the aforementioned traits. In conclusion, these S1-lines could be promising as a base for developing early-maturity and drought tolerant hybrids. This will help avoiding water stress events during growing season.

Ten sorghum genotypes (Sorghum bicolor L. Moench) were evaluated at three locations namely; Arab El-Awamer, Shandweel, and El-Fayoum Agric. Res. Stations in 2018 and 2019 growing seasons. Planting time at the three locations during the two years were during the 1 st week of July. The objectives of this study were to determine the performance and stability of ten sorghum across different locations of Egypt. The study was conducted using a randomized complete block design with four replications. Stability analysis for grain yield, 1000-grain weigh, plant height and days to 50% flowering were estimated using Tai's statistical method. A combined analysis of variance emphasized the significant effect of genotypes and locations for all studied traits. There was nonsignificant effect of year for all studied traits, except for 1000-grain weight. The effect of location on Sorghum grain yield and the other studied traits was greater than the effect of year. Hence, testing genotypes under many locations should be done rather than years. Significant effect of genotype x location interaction, suggesting that each genotype differentially responded to the change in the investigated locations. Based on Tai's stability analysis, 3 out of 10 tested sorghum genotypes i.e., (ASH-8 x ICSR-93002), (ASH-9 x ICSR-93002), and (ASH-12 x ICSR-93002) showed average stability and gave high yielding compared to the general mean and are thus the most stable grain sorghum genotypes for grain yield. Generally, Tai's stability method was facilitated the visual comparison and identification of superior genotypes, thereby supporting decisions grain sorghum genotypes for different environments.

Maize (Zea mays L.) is the third most important cereal grain in Egypt (after wheat and rice) but it is vulnerable to water stress which causes lead losses in both yield and quality. In the current study we evaluated 100 S1-lines along with their top-crosses using two testers under normal and water stress conditions. We used line × tester to assess general (GCA) and specific (SCA) combining ability effects for 100-grain weight and grain yield per plot; In addition, we estimated heritability for both traits. Result of line × tester analysis showed highly significant differences among parents, crosses vs parents., In addition, between testers and lines × testers for both traits under normal and water stress condition. The results, lines showed non-significant for 100-grain weight under normal and water stress condition. Grain yield per plot showed non-significant differences under normal condition while it showed significant under water stress condition. Under normal condition, S1-lines 56 and 88 possessed the highest 100-grain weight while, the highest values of 100-grain weight were found in cross combinations including S1-line 29 × SC162 and S1-line 61× TWC352. On the other hand, S1-lines 65 and 68 possessed the highest grain yield per plot while, the highest values of grain yield per plot were found in cross combinations including S1-line 86 × SC162 and S1-line 37× TWC352. Under normal condition, S1-lines 10 and 99 displayed positive and significant GCA effects for 100-grain weight while, S1-line 86 and 55 exhibited the maximum GCA effect for grain yield per plot. Top-crosses including S1-line 29×SC162 and S1-line 75×TWC352 were good specific combiners for 100-grain weight while, the top-crosses including S1-line 29×SC162 and S1-line 78×TWC352 were good specific combiners for grain yield per plot. Heritability in broad sense showed moderate highly estimates for both traits. Our results indicated the preponderance of dominance gene action in controlling both aforementioned traits. In conclusion, these S1-lines are promising to produce drought tolerant inbred line in the future, which may lead to produce drought tolerant hybrid.