Developing Novel Rice Genotypes Harboring Specific QTL Alleles Associated with High Grain Yield under Water Shortage Stress

Abstract

Rice is considered a strategic crop for many countries around the world, being the main cash crop for farmers. Water shortage stress occurrence as a result of climate change is among the main threats challenging rice breeders in the last few decades. In the current study, 19 Fn-lines were developed from four populations by crossing a reverse thermo-responsive genic male sterile (rTGMS) line, M.J.5460S, with the three high-quality Egyptian commercial cultivars Giza177, Sakha105, Sakha106 and the promising line GZ7768 as male parents. These newly developed lines, along with their parents, and two water shortage stress-tolerant international genotypes (Azucena and IRAT170), were cultivated under water-shortage stress conditions and compared with their performance under well-watered conditions. Results indicated that the yielding ability of the 19 newly developed lines exceeded those for the two Egyptian parents (Giza177 and Sakha105) under well-watered conditions. The lines M.J5460S/GIZA177-3 and M.J5460S/GIZA177-12 were the best performing genotypes under water shortage stress conditions. The genetic and heritability in broad sense estimates indicated that direct selection for grain yield (GY) under water-shortage stress is highly effective in the current study. Molecular marker analysis revealed that M.J5460S/GIZA177-3 had accumulated the quantitative trait loci (QTL)s, on the chromosomes 2, 3, and 9, which contribute to GY under water-shortage stress from their high yielding tolerant ancestor, M.J5460S. It could be concluded that those lines are high yielding under both well-watered and water-stress conditions harboring several QTLs for yield enhancement under both conditions and that the markers RM555, RM14551, RM3199, RM257, RM242, and RM410 are among the markers that could be used in marker-assisted selection (MAS) breeding programs for such stress condition.

Detection of Superior Rice Genotypes and Yield Stability under Different Nitrogen Levels Using AMMI Model and Stability Statistics

“…In recent years, great attention has been paid to sustainable cultivation. It mainly focuses on reaching the maximum yield potential of a genotype with a lower input of water, chemical fertilizers, and pesticides [ 4 , 15 ].…”

“…Breeders focus on the GEI effect to identify the yield stability of genotypes across different conditions and environments, which cannot be revealed by the separate effects of genotype or environment [ 10 , 11 , 12 , 13 , 14 ]. The GY heritability is exposed to variability across different environments [ 15 , 16 ], which hinders the accuracy of superior varietal selection processes [ 17 ]. Therefore, widely adapted genotypes with the ability to produce stable high yields across diversified environments constitute a major goal for rice breeders.…”

“…In recent years, there has been substantial interest in detecting both the yield and yield stability under different fertilizer conditions in different crops [ 38 ]. In our recent investigation, we estimated the yield stability of newly developed rice lines across different water treatments [ 15 ]. The present study aims to identify superior rice genotypes under low nitrogen input with stable yield performance over different N levels.…”

Physiological Evaluation of Wheat (<i>Triticum aestivum</i> L.) Genotypes at Pre-Anthesis Stage under Heat Stress Conditions

“…The key adaptive mechanism to heat stress involves accumulation of a variety of osmolytes such as proline [8] [9] and antioxidant enzymes [10]. Under high temperature, free proline is involved in osmotic adjustment, protecting pollen and several plant enzymes from heat injury and serving as a source of nitrogen and other metabolites [11] [12]. Accumulation of proline under heat stress occurs in Arabidopsis [13], canola [14], cotton [15] and wheat [16].…”