الفهرس 
Rice blast and yield lossesOnly 14 pages are availabe for public view
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Abstract
Objectives1- Transfer the resistance gene to blast from Japonica differential varieties to some Egyptian rice genotypes. 2- Estimation of combining ability and heterosis for morphological, yield and its components in parents and their F1 hybrids. 3- To study the relationship between some morphological, and the yield and its component characters by estimating correlation coefficient among the mentioned characters and estimates of cluster analysis for eight rice genotypes.
4- Studying the genetic diversity among some of rice and differential varieties by SSR marker related to rice blast. 5- To estimate the genetic parameters in F2 generations Methods & Results The present study was carried out at the experimental farm of Rice Research and Training Center (RRTC) and Gemmeza research station, during the three growing seasons of 2009, 2010 and 2011 and Rice Biotechnology Lab in RRTC, Kafr El-Sheikh, Egypt. The eight parental varieties in this study were sown in the growing season of 2009 in three sowing dates, (15 days) intervals to overcome the difference of heading date among the parental varieties. A half diallel cross meting design was conducted among the eight parental genotypes in 2009 growing season to produce 28 crosses The parental varieties and the resulting 28 crosses evaluated and arranged in a Randomized Complete Block Design (RCBD) experiment with three replications in 2010 growing season In 2011 growing season 28 F2 generations were evaluated to estimate the genetic parameters in F2 generations and All genotypes in F2 generations were tested for blast disease infection under three conditions (seedling stage, adult stage under natural condition and seedling stage under artificial inoculation) in two location (Sakha and Gemmeza research station).
Genotypes, parents and the resultant twenty eight crosses mean squares were found to be highly significant for all studied character in both F1 generations. The interactions of genotypes, parents and crosses were found to be significant for all characters in the F1 generation. The interaction of parent vs. crosses was found to be significant for all studied characters.
Conclusion:-
The phenotypic classes of F2 generations was found to be expected ratio 32 : 1 for crosses Sakha101 x BL1 which gave 486 plants resistance and 14 plants susceptible represented 99.2 % resistance (R) and 2.8 % susceptible (S), with P-value(0.90-0.95) multi complementary dominance genes.
Sakha101 and Sakha104 have sensitive alleles at Pib locus. The blast resistance which was found in the resistant F2 plants was due to the resistance Pib allele transferred from BL1. RM208 is co-segregated with Pib gene. We can use the RM208 marker to different between genotypes which have the Pib blast resistance gene or not. Also, we can use the BL1 international variety as a donor for Pib blast resistance gene.