Utilization of New African Rice Varieties for Breeding Egyptian Cultivars Tolerant to Water Deficit

Abstract

Breeding rice for abiotic stress tolerance is very important objective for rice breeders. Significantly reduce in yield due to drought-stress in most world countries, especially suffering from water lace as well as Egypt. Evaluating combining ability effects would provide valuable information that can be used for developing new drought tolerant lines. This study was conducted at Sakha Agricultural Research Station during 2014 to 2016 rice growing seasons to determine combining ability and gene action for grain yield and other important traits to identify the superior varieties/parents and crosses under both drought and optimum conditions. Six F 1 hybrids were generated by crossing four rice genotypes in a half diallel mating scheme in addition to their six F 2 populations after self-pollination. The four populations (P 1 , P 2 , F 1 and F 2 ) for all the six crosses were evaluated in a replicated field trial under drought and normal conditions. Drought stress significantly decreased the mean values of all the studied traits for parents and their hybrids compared with the control condition. Significant differences were observed among parents and their hybrids for most traits under both research conditions. General combining ability (GCA) and specific combining ability (SCA) means squares were highly significant for grain yield and most traits under test environments. The non-additive gene action played an important role in the inheritance of most studied traits. The parental genotypes NERICA3 and NERICA4 appeared to be the best general combiners for earliness and grain yield. The cross combinations; Giza178×NERICA3; Giza178×NERICA4 and NERICA3×NERICA4 in both F 1 and their F 2 generations were distinguished as specific combiners for grain yield and other related traits under normal and drought conditions. These results emphasized by positive heterosis over high parents followed by high values of inbreeding depression. Hence, these hybrids would be valuable in rice breeding for improving grain yield under drought stress condition.

Diallel Analysis of Different Rice Genotypes under Water Deficiency Conditions and Assessing Genetic Diversity Using SSR Markers

“…Hence, selection is possible to identify the desirable genotypes under such conditions. These results are in agreement with those obtained by Malemba et al (2017), Elgamal et al (2018), El-Sayed et al (2018 and Abd El-Hadi et al (2020). Mean squares due to parents vs. crosses were highly significant for all the studied traits, except leaf rolling trait under stress conditions, suggesting the presence of significant heterosis for these traits under both environments.…”

“…Generally, water deficit dramatically decreased the mean values of all the evaluated traits compared with normal irrigation, except leaf rolling and sterility percentage which significantly increased. These results are in good agreement with those reported by Abd Allah et al 2010, Sedeek et al (2012), Abd EL-Aty et al 2017and Elgamal et al (2018).…”

“…Therefore, breeding methods based on hybridization could be effective for the improvement of these traits. These results are in general agreement with those obtained by Sedeek et al (2012), Sathya and Jebaraj (2015), Abo-Youssef et al (2017), Malemba et al (2017), Elgamal et al (2018), El-Sayed et al (2018 and Bano and Singh (2019).…”

“…Both additive and non-additive gene actions were reported to be important in the inheritance of rice grain yield under normal and water deficit conditions by El-Hity et al (2016), Farid et al (2016), El-Adl et al (2019) and Abd El-Hadi et al (2020). However, the grain yield and other assessed traits under water deficit condition were mostly controlled by non-additive gene action as reported by Hasan et al (2015), Sathya and Jebaraj (2015), Malemba et al (2017), Elgamal et al (2018) and El-Sayed et al (2018).…”

“…Breeding for drought tolerance is crucial for maintaining stable yield (Oladosu et al, 2018). In Egypt, rice occupies about 22% of the total cultivated area in the summer season (Elgamal et al, 2018). It consumes more than 20% of the total irrigation water resources.…”