Role of some growth Characters in Improving the Drought Tolerance in Rice.

Abstract

The present investigation was carried out at the farm of the of Rice Research and Training Center, Sakha, Kafr El-Sheikh, Egypt, during 2014 and 2015 seasons to evaluate some growth and yield parameters in rice by using eight rice varieties under normal and drought conditions. The results indicated that, the parents Sakha 106, Giza178, Nerica4 and WAB880 and the crosses (Sakha106 × Giza177), (Sakha106 x Sakha102), (Giza178 × Giza177), (WAB880 × Nerica4) and (IRAT112 × Nerica4) were found to have the most desirable mean values under the two environments and their combined data. Genotypes, parents and the crosses mean squares and their interactions with environments were found to be highly significant for all studied characters. The most pronounced useful heterosis effects relative to the better parents for all characters were detected in the crosses (Sakha106× Giza 177), (IRAT170 × Nerica4),( Giza 177 × IRAT112),( Giza177 × Nerica4) and (Sakha102 × IRAT112) under the two environments and their combined data. Over dominance was detected in most crosses for plant height, number of tillers / plant, panicle length, relative water content and grain yield/plant. The values of potence ratio was less than unity in most crosses for days to heading, chlorophyll content, flag leaf area, flag leaf angle and leaf rolling. The results showed also high genetic variance for days to heading, plant height and flag leaf angle. However moderate values were obtained for chlorophyll content, flag leaf area and grain yield / plant, and low estimates of number of tiller/ plant, relative water content, panicle length and leaf rolling. High heritability values had been obtained for plant height, chlorophyll content, flag leaf area, flag leaf angle and grain yield / plant. The results obtained here indicates the relative importance of physiological parameters such as chlorophyll content, flag leaf area, flag leaf angle, relative water content and leaf rolling as selection criteria for drought tolerance. Also, the existence of significant amounts of genetic variation among the tested materials suggests their potential in breeding for water deficit tolerant rice genotypes.