Identification of superior and usable maintainer line for the development of heterotic hybrids

In developing hybrid crops, the use of cytoplasmic male sterility system is possible only when effective maintainers and restorers are identified. Therefore, it is essential to identify maintainers and restorers from local germplasm for development of component lines in a hybrid program. Locally adapted maintainers and restorers which show complete sterility and consistently high degree of restoration would be of great value in commercializing hybrids. Therefore, evaluation and selection of maintainer lines by yield trial on stable generation and gathering information for yield and its components is crucial. This study was conducted at the experimental area of the PhilRice CES to identify and select outstanding B-line for conversion to CMS line. A total of 32 entries from the F6 and F7 generations were subjected for yield trial following the Randomized Complete Block Design with three replications. Maintainer line of released three-line hybrids IR68897B (Mestiso 3 and Mestiso 32) and IR80559B (Mestiso 30) were used as checks. Yield and other yield traits such as maturity, plant height, productive tiller number, 1000 grain weight, total number of grains and grain yield were gathered. Among the 32 entries, PR43282-B-42-4 (8.6 t/ha), PR40510-5-2-4 (8.8 t/ha) and PR46175 HY-4-3-2-1-1 (8.8 t/ha), PR46172 HY-3-1-1-2-1 (9.0 t/ha), PR46160 HY-8-3-1-3-1 (9.6 t/ha), PR43282-B-27-4 (9.9 t/ha) and PR46185 HY (10.46 t/ha) had reached above 8 t/ha compared to its checks with a yield of 6.1 t/ha (IR68897B) and 4.3 t/ha (IR80559B). Yield advantage over the best performing maintainer line (IR68897B) ranged from 41.9% to 71.98% of the top seven entries. The following entries will be nominated for CMS line conversion through backcrossing base on the data gathered. With the rigid selection of best maintainer lines for CMS conversion, it will eventually lead to the development of high yielding hybrids which will consequently help achieve rice sufficiency.