IMPROVEMENT OF GENETIC PURITY FOR THE CYTOPLASMIC MALE STERILE LINE IR58025A WITH ITS MAINTAINER OF HYBRID RICE UNDER EGYPTIAN CONDITIONS

the present investigation aims at improving the genetic purity of Cytoplasmic Male Sterile line (CMS) IR58025A and its maintainer line IR58025B during three growing seasons of 2014, 2015 and 2016. Seeds of parental line were planted in 2014 season in isolated plots to obtain the parent seeds. This study was performed at the experiment farm of Rice Research Dept., Sakha, Kafr-Elsheikh, and Plant Pathology and Biotechnology Lap., Faculty of Agriculture, Kafr-Elsheikh univ. A total of 50 single crosses were made and harvested separately for the CMS line with its maintainer line to be evaluated during 2015 season. Some seeds of each of the crosses were used for identification, and the rest were kept to be grown with their maintainer seeds for multiplication. The same methods were repeated during, 2015 and 2016 seasons. Five replicates were used in randomized complete block design. Genetic markers were used to develop a reliable Polymerase Chain Reaction (PCR) assay to distinguish IR58025A and its maintainer. The primers used were; RMT6, cms and RM239. The maximum impurity value for IR58025A line was 4% after three paired-cross evaluations. The present investigation showed highly significant variance among the studied characters and the values of heritability in broad sense for IR58025A line were 89.08 and 97.84 for flag leaf area and stigma breadth, respectively. The recorded data for the primer RMT6 showed two DNA bands with molecular size of 200 and 210 bp for line IR 58025A and 200 bp for its maintainer. The cms primer showed only one DNA band with molecular size 400 bp for IR58025A line and it was absent in its maintainer. RM239 showed one DNA band with molecular size of 160 bp in IR58025A and it was absent in its maintainer, indicating that these primers can be used as marker aided selection (MAS) for pure parental line to develop new hybrid rice variety.