Line x tester approach with 12 lines and 3 testers was used to assess maize combining ability. The 36 crosses and two checks were tested under regular irrigation and water shortage in RCBD design with three replications. The topcross L9 x M2 performed best for days to 50% silking, while the cross L7 x CIMMYT14 for grain yield plant-1. Non-additive gene action was predominant for all traits and GCA was more stable under varied environmental conditions than SCA. Lines L5 and L8 had favorable GCA impacts for yield and some related characters. Desirable SCA effects for days to 50% were obtained for the cross L9 x M8. The cross L7 x CIMMYT14 and L11 x M8 gave the best SCA values for grain yield plant-1 and one or more other traits. The cross L9 x M8 gave the best heteroboltosis for days to 50% relative to both checks. Moreover, the most desirable heterotic effects for grain yield plant-1 were detected for the crosses L5 x M2 under drought stress and combined data and the cross L7 x CIMMYT14 under normal irrigation relative to both checks.

This investigation was undertaken at the Experimental Farm of the Faculty of Agriculture, Moshtohor, Benha University during the two summer growing seasons of 2018 and 2019. To estimate combining ability under two nitrogen levels and superiority% relative two check hybrids for fivequantitative characters. N levels and genotypes mean squares were significant for all studied traits. Mean squares due to genotypes x N levels were significant obtained for all studied traits.SCA was higher than GCA for all studied traits revealing that the non-additive effects were controlled these traits. The overall study of GCA effects suggested that parentsM65, M66 and M48 were significant for general combiner for grain yield, M70 and M57 for earliness and M50 and M70 for short plants and ear stature. However, the genotypesM65xM10, M17xM10, M37xM10 and M48xCLM550 showed high SCA effect for grain yield plant-1. The maximum heterosis was recorded by the crossM48xCLM550 in combined across nitrogen levelsthey out-yieldedSC128 and SC2031reached 18.00 and 14.00%, respectively.100-grain weight were correlated significantly with grain yield with r values being 0.707** in the combined analysis.Factor analysis for combined across N levels divided characters of maize into three factors accounted for 78.63% of the total variability. The first factor contributed by 39.14% included ear length, ear diameter, No. rows ear-1, No. kernels row-1, 100-kernel weight and shelling%. The second factor accounted for 24.83% and is mainly loaded by days to 50% tasseling and silking. The third factor accounted for 14.66% is mainly described by plant and ear heights.

Thirty new top crosses of maize were tested under full irrigation and water deficit circumstances after being crossed between ten new maize inbred lines and three testers. To evaluate the combining ability of several traits in maize, these crosses were set in an RCBD design with three replications along with two checks in both environments. Desirable mean values for 50% silking were detected for the crosses L25xM8 under normal irrigation and L21xM8 under water deficit. The most desirable mean values for grain yield plant-1 were obtained for the cross L29xM8 followed by L23xM4 under normal irrigation and L26xM4 under water shortage. For all examined traits, non-additive was more important than additive in all environments. The tester T1 (M4) was the best for days to 50% silking, chlorophyll content, and grain yield, while the line L2 exhibited the best GCA effects for 100 kernel weight and grain yield. The highest significant and negative SCA effects for days to 50% were detected for the crosses L25xM8 under normal irrigation and combined data. For grain yield, the cross L28x M4 gave the best SCA effects under E1 and L29x M8 under E2 and combined analysis. The most desirable heterosis for grain yield relative to both checks was obtained for the cross L23xM4 in the combined analysis. Also, the cross L26xM4 expressed desirable heterosis for most traits under both environments. The cross L29xM8 recorded the best heterosis values for days to 50% silking, 100-kernel weight, and grain yield under normal irrigation

The genetic behavior of thirteen morphophysiological, yield and quality traits in rice was studied using L x T model. Six parent varieties, namely, SK104, SK106, GZ11332, SK108, SK109, SK101 and four testers Viz., IHL17, IHL65, IHL175, SR303 of Oryza sativa were used in this study in 2023 and 2024. The resultant twenty-four crosses were scrutinized in RCBD design with three replications. Results indicated that mean squares due to all crosses were significant for morphophysiological, yield and quality characteristics. The cross SK109xSR303 exhibited the best mean values for plant height, panicle length, panicle weight, grain yield plan-1, harvest index and hulling%. Non-additive gene action was responsible for the inheritance of all traits studied. The parent SK109 was the best general combiner for seven out of the thirteen traits, while the tester SR303 expressed significant and desirable GCA effects for eight out of the thirteen crosses. The cross SK109xSR303 elucidated the best SCA effects for days to 50% heading, chlorophyll content and No. of panicle plant-1, whereas the cross SK106xIHL175 expressed the most desirable SCA effects for grain yield plant-1. The cross SK109xSR303 exhibited the best desirable mid-parent and better-parent heterosis for panicle length and grain shape, as well as mid-parent heterosis for grain yield plant-1 and harvest index.

Two field experiments were conducted at the Experiment and Research Center, Fac. Agric., Moshtohor, Benha Univ., Qalubia Governorate, Egypt, in the summer seasons 2021 and 2022 to study the performance of seven genotypes of rice under three levels of nano-N spraying on growth, yield and its attributes. The most important results obtained from this study can be summarized as follows:The results of the study revealed that the maximum highest No. tillers plant-1 (23.26 tiller), No. spikes plant-1 (19.98 panicle), panicle length (25.41 cm), panicle weight (4.39 g), 1000-grain weight (29.11 g) and grain yield plant-1 (59.48 g) obtained by spraying with 800 ml fed-1 concentration treatment, while, spraying with zero and 400 ml fed-1 concentration treatments were decreased No. days to 50% flowering in the combined analyses.Rice genotypes were highly significant affected on all of the studied characters. G2 genotype was the earliest in No. days to 50% flowering compared with other rice genotypes, whereas, G1 genotype gave the highest values of No. tillers plant-1, No. spikes plant-1, panicle weight, 1000-grain weight and grain yield plant-1, while, G5 genotype gave the highest value of panicle length in the combined analyses. Effect of the interaction between nano-N spraying treatments and rice genotypes were showed highly significant for No. tillers plant-1, No. spikes plant-1, panicle length, panicle weight, 1000-grain weight and grain yield plant-1. Generally, spraying with 800 ml fed-1 concentration treatment under G1 genotype recorded the highest values for these traits except panicle length in combined data. It could be complemented that under the conditions of the experiment, planting G1 genotype with spraying with 800 ml fed-1 concentration is recommended.