MOLECULAR AND CYTOGENETICAL VARIATIONS OF SOME CYTOPLASMIC MALE STERILE LINES AND THEIR MAINTAINERS IN RICE

Abstract

Molecular, isozyme, cytological and morphological variations were studied to detect the variations between cytoplasmic male sterile (CMS) lines, their maintainer lines and two local cultivars of rice (Oryza sativa). The lines, which were used in this investigation, were as follow:- 1. Four CMS lines (IR6770lA, IR68276A, IR68277A and IR68884A). 2. Four maintainer lines (IR6770lB, IR68276B, IR68277B and lR68884B). 3. Two local Egyptian cultivars (Gizal77 and Gizal8l). The study was conducted in the farm of the Faculty of Agriculture in Kafr EL-Sheikh. In order to maintain the CMS lines, each CMS line was crossed to its maintainer line. Seven morphological characters were studied in this investigation. these characters were as follow: - 1. Plant height. 4. Flag leaf width. 7. Heading date. 2. Number of tillers per plant. 5. Panicle length. 3. Flag leaf length. 6. Panicle excision. In order to detect cytological variations the chromosome associations per cell from diakinesis to quartet and the chromosome behavior in anaphase and telophse at the first and second meiotic divisions and the quartet stage were studied. Isozyme variations included esterase and peroxidase isozymes of the leaves of 25 days old seedlings were studied using a polyacrylamid gel electrophoresis technique. On the other hand, molecular variations of mitochondrial DNA often days old seedling grown in dark was studied by agarose gel electrophoresis.