Combining ability analysis of the maintainer and restorer lines for cytoplasmic male sterile (CMS) system of hybrid rice [electronic resource].

Includes references.

Five cultivars of rice were crossed to obtain 20 F1 hybrids, through diallel hybrid mating design. These cultivars included three introduced maintainers and two Egyptian restorers. Griffing's 1956 Method 1, Model 1 was employed for this purpose. The five parents and their 20 F15 (including reciprocals) were grown in a randomized block design with three replications at RRTC farm, Sakha Kafr EI-Sheikh, Egypt. Data were collected on 12 traits including agronomic, yield and its components and panicle traits. GCA and SCA were significant for all the studied traits except harvest index. GCA/SCA ratio was found to be greater than unity for heading date, plant height, harvest index, 100-grain. weight, panicle length, spikelets panicle-l and spikelet fertility%. This finding indicates that additive and additive x additive types of gene action were of greater importance in the inheritance of these traits. On the other hand, GCA/SCA ratios were found to be less than unity for the rest of the studied traits, indicating that the non¬additive type of gene action including dominance was of great importance in the inheritance of these traits. The maintainer line IR68886B was the best general combiner for most of the studied traits followed by the restorer lines Giza 178R and Giza 182R. The hybrid combinations IR68886B x Giza 178R, IR68886B x Giza 182R and IR692625B x Giza 178R showed high SCA effects for the most studied traits and were considered as the best combinations. Thus, these hybrids could be useful for the hybrid rice program.

Summary in Arabic.

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