Role of some growth Characters in Improving the Drought Tolerance in Rice.

Abstract

The present investigation was carried out at the farm of the of Rice Research and Training Center, Sakha, Kafr El-Sheikh, Egypt, during 2014 and 2015 seasons to evaluate some growth and yield parameters in rice by using eight rice varieties under normal and drought conditions. The results indicated that, the parents Sakha 106, Giza178, Nerica4 and WAB880 and the crosses (Sakha106 × Giza177), (Sakha106 x Sakha102), (Giza178 × Giza177), (WAB880 × Nerica4) and (IRAT112 × Nerica4) were found to have the most desirable mean values under the two environments and their combined data. Genotypes, parents and the crosses mean squares and their interactions with environments were found to be highly significant for all studied characters. The most pronounced useful heterosis effects relative to the better parents for all characters were detected in the crosses (Sakha106× Giza 177), (IRAT170 × Nerica4),(Giza 177 × IRAT112),(Giza177 × Nerica4) and (Sakha102 × IRAT112) under the two environments and their combined data. Over dominance was detected in most crosses for plant height, number of tillers / plant, panicle length, relative water content and grain yield/plant. The values of potence ratio was less than unity in most crosses for days to heading, chlorophyll content, flag leaf area, flag leaf angle and leaf rolling. The results showed also high genetic variance for days to heading, plant height and flag leaf angle. However moderate values were obtained for chlorophyll content, flag leaf area and grain yield / plant, and low estimates of number of tiller/ plant, relative water content, panicle length and leaf rolling. High heritability values had been obtained for plant height, chlorophyll content, flag leaf area, flag leaf angle and grain yield / plant. The results obtained here indicates the relative importance of physiological parameters such as chlorophyll content, flag leaf area, flag leaf angle, relative water content and leaf rolling as selection criteria for drought tolerance. Also, the existence of significant amounts of genetic variation among the tested materials suggests their potential in breeding for water deficit tolerant rice genotypes.

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.…”

“…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).…”

“…Consequently, one or more of these crosses could be used in rice breeding programs for producing hybrid rice under normal and stress conditions. Positive and significant heterosis for grain and some of its components in rice under normal and water deficit conditions have been reported by Sultan et al (2014), Ushakumari et al (2014), El-Sayed et al (2018 and Abd El-Hadi et al (2020).…”

“…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).…”