GENETICAL STUDIES ON ROOT SYSTEM AND YIELD AND ITS COMPONENTS TRAITS UNDER WATER LIMIT CONDITION IN RICE (Oryza sativa L.)

Abstract

Water limit is one of the major a biotic stress limiting plant production in worldwide. The research work of the present study was carried out at the Experimental Farm of the Rice Research and Training Center (RRTC), Sakha, Kafr El-Sheikh, Egypt, during the three successive rice seasons 2010, 2011 and 2012, to study the genetic effects on some of root system related to water limit and yield and its component traits under water limit condition. Six rice genotypes i.e. Giza 177, Sakha 101, GZ 7456-13-6-5-3, Sakha 105 (sensitive to drought stress), IRAT 112 and IRAT 170 (tolerant to drought stress), were chosen for this study. The results of this investigation revealed that both general and specific combining ability variances were found to be highly significant for all studied traits except root thickness, root dry weight and 1000-grain weight, indicating the importance of both additive and non-additive genetic variance in determining the inheritance of these studied traits i.e. root length, root volume, plant height, No. of days to heading, , No. of panicles/plant, No. of filled grains/panicle and grain yield/plant. With the exception of No. of panicles/plant and grain yield/plant, the GCA/SCA variances were found to be greater than unity for all the studied traits except for No. of panicles/plant and grain yield/plant, suggesting greater importance of additive genetic variance in the inheritance of these traits. Therefore, it could be concluded that selection procedures based on the accumulation of additive effect would be successful in improving of these traits. The results showed that IRAT 112 and IRAT 170 were highly significant and positive general combining ability effects for maximum root length, root thickness, root volume, root dry weight and yield and its component traits under water limit condition indicating that these genotypes could be considered as good combiners for the improvement of these traits i.e. Sakha 105 x IRAT 112 for maximum root length, Sakha 101 x IRAT 112 for root thickness, Giza 177 x IRAT 112 for root volume, IRAT 112x IRAT 170 for root dry weight and Sakha 101 x IRAT 170,Sakha 101 x IRAT 112 for grain yield/plant under water limit condition. Frequency distribution of phenotypes for each trait in F2 and their parents, all studied traits approximately fit normal distribution, F2 plants having phenotypic values greater than the higher parent and less than the lower parent (Transgressive Segregates) were observed for all studied traits.

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

“…Moreover, none of the parents exhibited significant GCA effects for all the measured traits under both conditions. These results are in agreement with those reported by Sedeek et al (2012), Malemba et al (2017) and Abd El-Hadi et al (2020).…”

“…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).…”

Evaluation of New Promising Rice Lines Under Water Deficit Conditions Based on Grain Yield, Quality and Stress Tolerance Indices تقييم سلالالات مبشرة من الأرز تحت ظروف نقص المياه على أساس محصول الحبوب وصفات الجودة و دلائل الإجهاد المائي

“…It is noteworthy that the mean values of all studied characters under normal irrigation were higher than those recorded under water deficit conditions, except elongation trait. These results are in good agreement with those reported by Abd Allah et al, (2010), Sedeek et al, (2012), Abd EL-Aty et al, (2017), Elgamal et al, (2018) and Mumtaz et al, (2020).…”

Evaluation of Iraqi Rice Cultivars for Their Tolerance to Drought Stress

“…Irat112 was developed in 1983 by hybridization with the mutant variety IRAT13 (obtained by irradiation with chronic gamma rays). Higher tillering, early maturity, and drought tolerance are the main attributes of the variety [70]. Nerica7 (New Rice for Africa) was released in the year 2000 and developed by crossing O. sativa and O. glaberrima (often called African rice).…”