Estimation of genetic variability and frequency distribution in F2 generation of rice under normal and deficit water supply

The investigation was conducted at the experimental farm of the Rice Research and Training Centre, Kafr el Sheikh, Egypt, during the summer seasons from 2017 to 2019 using the experimental material consisting two populations with their two parents (P1, P2, F1 and F2) to study the variability in the F2 population of four crosses: IR 78,936-B-B-B-B (water deficit tolerant) x Giza 177 (water deficit sensitive), FL-496 (moderately water deficit tolerant) x Giza 177, IR 78,936-B-B-B-B (water deficit tolerant) x Giza 178 (moderately water deficit tolerant), FL-496 × Giza 178 under normal (NWS) and deficit water supply (DWS). The experiment was conducted in a randomized complete block design with three replications. The results indicated that the phenotypic values of the measured characters were significantly different between the two parents of all the studied crosses under the two water supply conditions. The means of all the studied characters under DWS were lower than the means under NWS, but the yields and the yield components under DWS varied greatly among the parents due to stress. The averages of the measured traits of the F1 plants and the F2 populations in all crosses were near the averages of those of the parents. The results showed no consistent reduction in heritability under DWS compared to NWS. High heritability in a broad sense coupled with high genetic advance (GA) was observed for grain yield in Cross 1 under the two studied conditions offering good scope for selection

Inheritance of some flag leaf and yield characteristics by half-diallel analysis in rice crops (Oryza Sativa L.)

This study was conducted during 2018 and 2019 at the Rice Research and Training Centre farm, Sakha, Kafr el Sheikh, Egypt. Six genotypes of rice, Sakha 101, Giza 178, Irat 170, Wab-56-104, IR65500-127 and IR69853 were half-diallel crossed to estimate the combining ability effect as well as sink and yield potential in rice. Sink capacity (number of spikelets/panicle and 1000-grain weight), source leaf (flag leaf length, flag leaf width and flag leaf area), source-sink association (number of spikelets/panicle to flag leaf area ratio) and traits of yield components (filled grains number/panicle and panicle number) plant and grain yield/plant) were analysed. The results indicated that both general and specific combining ability were highly significant for all the studied characteristics. IR65500-127, Giza 178, and Sakha 101 were identified as good parents, so these parents were suggested for a further recombinant breeding programme. The cross of 3 × 5 was found to be superior for flag leaf width and grain yield, while the cross of 1 × 4 was found to be superior for flag leaf length, flag leaf length/width ratio, chlorophyll content and number of panicles/plant. Advancing these crosses and effected selections in segregating generation would be helpful to develop high yielding varieties. The genetic parameter showed a dominant deviation in one direction was controlled for all characters except flag leaf length. The analysis of the regression line showed that the over-dominance played an important role in the inheritance of gene action for grain yield/plant

Effect of Planting Methods on the Quality of Three Egyptian Rice Varieties

In Egypt, the traditional transplanting method of rice planting is substituted by broadcasting and dibbling recently. This paper studies the effects and the changes occur in different rice varieties due to different methods on grain quality and amino acids of rice. Three Egyptian rice cultivars belonging to japonica, japonica/indica and indica subspecies were investigated for grain quality, protein and amino acid composition under three planting methods, i.e., broadcasting, seedling transplanting and dibbling. A strip plot design with three replications was used; the investigated three rice cultivars occupied the horizontal main plot, while three planting methods were devoted to the vertical main plot. The method of planting did not affect significantly the grain dimension, but it affected significantly the milling characters and the 1,000-grain weight. The highest milling characters and 1,000-grain weight came from transplanting, while the lowest one from the dibbling method. There was no significant difference between transplanting and broadcasting in milling characters and 1,000-grain weight. The chemical and cooking characters of grains showed no significant differences in moisture content and gelatinization temperature characters, while the differences in protein content and elongation were significant among the varieties and planting methods. The interaction between the planting method and rice had significant effect on the protein content. The most important essential amino acids according to the FAO/WHO pattern were not affected significantly by the different methods of planting. This means that the biological value of rice grains is not affected by different methods of planting