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The present study was carried out at Agronomy Department, Faculty of Agriculture, Kafrelsheikh University, Egypt during the two successive seasons 2013 and 2014. The material of this study included thirteen rice genotypes viz., Sakha 102, Sakha 104, Sakha 105, Sakha 106, Giza 177, Giza 178, IET 1444, IRAT 170, IRAT 112, Hybrid rice 2, Moroberekan, WAB 878 and Gaori. Such genotypes were sown on three different sowing dates i.e. 15 th April, 1 st May and 15 th May under three nitrogen fertilization levels; 40, 60 and 80 kg N/fed. Split plot design with three replications was used for each sowing date. The present investigation was undertaken to study yield potential, genetic diversity, correlation and path analysis as well as genetic variability of the aforementioned rice genotypes under the different sowing dates. The mean squares due to sowing dates, nitrogen levels, genotypes and the first order as well as the second order interactions were significant or highly significant for most of the studied characters. The first sowing date (15 th April) recorded the most desirable estimates for panicle length, number of spikelets/ panicle, number of grains/ panicle, fertility percentage, 1000-grain weight and grain yield. The intermediate nitrogen level (60 kg N/fed) recorded the most favorable values for grain yield, number of grains/ panicle and panicle length. As a mean over sowing dates and nitrogen levels, grain yield was maximized in case of Hybrid rice 2, IET 1444 and Giza 178. Hybrid rice 2 recorded the most desirable estimates of number of grains/ panicle and number of panicles/ panicles either under the first or the second sowing dates associated with the highest nitrogen level. Grain yield revealed significant positive correlation with each of, panicle length, number of spikelets/ panicle, number of grains/ panicle and number of panicles/ plant under all sowing dates, suggesting that grain yield can be improved in these rice genotypes through selection based on these traits. The relationship between most pairs of traits was approximately constant and showed the same direction under all environments (sowing dates). Path coefficient analysis revealed that under the third sowing dates, number of grains/ panicle detected the highest positive direct effect on grain yield followed by number of panicles/ plant and days to 50% heading; 0.80, 0.626 and 0.378, respectively. While, number of spikelets/ panicle, fertility percentage and number of panicles/ plant recorded the highest positive direct effect on grain yield under the intermediate sowing date. Moreover, number of spikelets/ panicle and panicle length were the most contributors at early sowing date. Grain yield exhibited higher PCV and GCV estimates compared with the other traits under all sowing dates while, such estimates were minimized in case of fertility percentage. The heritability estimates in broad sense were either moderate or high for all the characters under consideration under all sowing dates. Number of days to 50% heading showed estimates of broad sense heritability more than 98% under all sowing dates. While, such estimates were less than 80% in case of number of panicles/ plant; 76.46% (under the first sowing date), grain yield; 71.28% (under the intermediate sowing date) and number of grains/ panicle; 58.3% (under the third sowing date). The genetic advance under selection as percentage of mean was found to be high for grain yield; 29.9, 36.6 and 30.3% for the three sowing dates, respectively. High El-Degwy, I. S. and M. M. Kamara 696 heritability estimates coupled with high genetic advance were recorded for number of number of days to 50% heading, plant height and panicle length. Moreover, moderate heritability estimates associated with high genetic advance were observed for grain yield. Based on cluster analysis, the genotypes were categorized into four clusters. The First cluster contained 4 genotypes; Giza 177, Sakha105, Sakha106 and Gaori. The second group included Sakha 102, Sakha 104 and hybrid rice 2. The third cluster including two indica rice genotypes; Giza 178 and IET 1444. There are two sub groups in cluster four. Moroberekan rice variety was separated into one sub group. The other sub group including drought tolerance genotypes; IRAT 170, IRAT and WAB 878. The Dendrogram of cluster analysis classified the nine traits in two clusters. The first one comprised grain yield and three of major yield-related traits viz., number of panicles/ plant, 1000-grain weight and panicle length. There were two sub groups in cluster two. One of the sub group belonged to cluster two included heading date, plant height and fertility percentage. While, number of grains/ panicles and number of spikelets/ panicle were separated in the other sub group.

YIELD POTENTIAL, GENETIC DIVERSITY, CORRELATION AND PATH COEFFICIENT ANALYSIS IN RICE UNDER VARIABLE ENVIRONMENTS