| Popis: |
The current study was carried out at Rice Research and TrainingCenter, Sakha, Kafr El-Sheikh, Egypt during the two successive seasons; 2011 and 2012. It aimed to investigate the performance of fourteen rice genotypes, including six newly elite lines, as well as seven commercial rice varieties to estimate the genetic parameters i.e. phenotypic, genotypic coefficients of variations, heritability and genetic advance from selection, to estimate the type and magnitude of associations among yield and thirteen yield-related characters. These characters were measured as phenotypic correlation as well as using path coefficients to detect the contributions of different traits to yield variations. Significant differences were detected among rice genotypes for all studied traits. The estimates of grain yield were highest in case of Giza 178 and Sakha 101 rice cultivars. Rice lines involved in this study recorded reliable estimates for yield components but, the lack of their yields may be due to high infestation by the rice stem borer. The genetic variance was highly significant for all the studied traits, indicating a wide range of genetic variability. Dead heart and white head percentages exhibited the highest phenotypic coefficients variability and genotypic coefficients variability estimates, indicating large variations among the tested rice genotypes in such traits. High heritability estimates coupled with high genetic gain were recorded for dead heart and white head. High heritability estimates coupled with moderate genetic gain were recorded for flag leaf area, no. of filled grains/panicle, no. of spikelet's/panicle and grain yield. Grain yield was significantly correlated with no. of tillers/panicle (0.556) and no. of panicles/plant (0.49). Strong positive associations were recorded between plant height and each of heading date, flag leaf area, dead heart and white head while, no. of panicles/plant had significant positive correlation with No. of tillers/plant(0.83), third internode length (0.39) and grain yield (0.49). Path coefficients analysis indicated that no. of spikelets/panicle followed by flag leaf area, no. of tillers/plant, heading date and panicle length had desirable direct effects on grain yield variations. While, white head percentage and no. of filled grains panicle played an important role on the genotypic variations of no. of tillers/panicle. From the previous results, it is evident that the five aforementioned characters could be used as selection criteria to improve grain yield. |
