Amgad Elgamal

Rice (Oryza sativa L.) has an impressive range of phenotypic and genetic diversity, making it an important crop for global food security. Since rice phenotypic and genetic diversity are essential for enhancing the sustainability of rice production, an understanding of these variations is crucial for breeding efforts. Numerous factors, such as plant height, panicle number, grain properties, etc., exhibit phenotypic diversity in rice. Moreover, genetic diversity is essential for breeding and enhancing rice in multiple manners. This research investigates the phenotypic diversity of thirteen promising lines relative to their parents. Since the genetic effect reflects the plant’s phenotype, forty SSR markers were used to investigate the genotypic diversity. Generally, six promising genotypes produced much better grain yields than their parents. Across two years, the number of filled grains panicle⁻¹ and the number of unfilled grains panicle⁻¹ had the highest phenotypic and genotypic coefficients of variability percentage. The challenges towards novel variety with distinct characteristics were met in several promising lines under examination, which showed a significant and positive association between the grain yield and the number of panicles per plant, the number of filled grains per panicle, and the 1000-grain weight. Furthermore, five SSR markers were discovered to be polymorphic during the genetic diversity investigation, and the genotypes were classified into five clusters based on SSR marker data. The findings, together with further details, can be used to release novel and unique varieties.

The present investigation was conducted under normal and salinity conditions during the two rice successive seasons of 2020 and 2021. Three CMS lines of rice, IR69625A, G46A and GAB-A were used as female parents. In addition, four Egyptian tester lines viz., Giza179, PR5, PR6 and GZ9399 were used as testers beside their twelve F1 crosses. A randomized complete block design with three replications was used and the data were analyzed according to line × tester design. The results indicated highly significant differences among genotypes, parents, crosses and parents vs. crosses under the two environments (normal and salinity conditions).The results showed that dominance genetic variance (σ²D) was greater than additive genetic variance for Plant height, Number of panicles/plant, Spikelet fertility %, 1000-grain weight, Grain yield/plant, sodium content and potassium content under normal and salinity conditions, Panicle weight under salinity condition, indicating that non-additive gene action played an important role in the inheritance of this trait. For heterosis over the mid-parents (H.M.P.%): The most desirable hybrids; For grain yield plant-1, the highly values and highly significant heterosis based on mid-parents for grain yield plant-1 were observed for the crosses GAB-A/PR5, GAB-A/PR6, GAB-A/GZ9399, G46A/GZ9399, G46A/PR6 and G46A/PR6 under both conditions. The following genotypes could use in breeding program and expected improvement in such traits under normal and saline condition, G46A, PR6, GZ9399, Giza179 and GAB-A as a good donor. G46A/PR6, G46A/PR5, GAB-A/ PR6 and IR69625A/Giza179 could use as good crosses.

The present investigation was carried out at Sakha agricultural research station, Kafr El-Sheikh and clayey saline soil at the experimental farm of El-Sirw Agricultural Research Station, Damietta governorate (31°14′N and 31°48′E) at the northern east of the Delta, Agriculture Research Center, Egypt, during 2021 and 2022 seasons. Four rice varietiesi.e.Giza178, Giza179, GZ9399-4-1-1-3-2-2, and Sakha super 300, as a female lines and IET 1444 , Sal 010, GZ 1368 and IR 45427 as tester were utilized. The parental varieties were crossed by using line & tester's analysis and sixteen crosses were obtained. The F1 and their parents were grown and evaluated under saline soil. The studied characters were No of panicles/plant, panicle length (cm), number of filled grains/panicle, sterility percentage/ panicle (%), panicle weight (gm.), 1000-grain weight (gm.), grain yield/plant (gm/plant) and harvest index (%). The obtained results indicated that, the parents, Giza178, Giza179 and IET 1444 were the best parental for general combining ability for studied traits. Meanwhile, the crosses, Giza179×IR45427, Giza178×IET 1444 and Giza179× Sal 010 were the best performing crosses under saline soil conditions and could be used as the most effective for getting promising lines. From this results could be concluded that, the additive genetic variance play important role in the inheritance for grain yield and harvest index characters, so, pedigree method will be effective to develop new promising lines from these crosses under saline soil condition.

The current study was carried out at the Experimental Farm of El-Gemmeiza Agricultural Research Station, ARC, Egypt, in two seasons 2018/19 and 2019/20. Eight bread wheat promising lines consists of five promising lines (1, 2, 3, 4 and 5) and three commercial cultivars (Sahel 1, Sids1 and Gemmeiza 9). In first season, the eight wheat genotypes were crossed using a half diallel mating design excluding reciprocal. These crosses (28) with its parents (8) were evaluated under normal and water stress conditions through second season. The results cleared that both additive and non-additive genetic variances were found to be involved in the inheritance of the studied trails, however, non-additive gene effects more important. Water stress treatment decreased significantly means of all genotypes for all the studied characters. The reduction of grain yield plant-1 was showed values varied from 6.6% to 37.42%. Two genotypes Line 5 and Sahel 1 were found be the best general combiners for no. of days to maturity, no. of kernels spike-1 and 1000-kernel weight, The cross Line 5 x Sids 1 showed desirable SCA effects for both no. of spikes plant-1 and grain yield under both normal and water stress conditions and their combined data. Low heritability estimates in narrow sense were detected for no. of days to maturity and grain plant-1, meanwhile, the remaining characters had moderate to high estimates. The most tolerant genotype for water stress was line 3 and the combination Line 4 x Sids 1 according to SSI, TOL and YI indices. Moreover, the crosses Line 1 x Line 3, Line 2 x Gemmeiza 9, Line 3 x Sahel 1 and Line 4 x Line 5 were the most tolerant as they recorded lower values for both SSI and TOL indices. Positive and significant correlations were found among grain yield plant-1 with plant height.