Breeding of High-quality, Early-maturing Indica Rice CMS Lines

  Objective  To breed high-quality, early-maturing CMS lines of Indica rice.

  Method  The F₄ lines derived from Quan 5B×Tianfeng B hybrid was used as male parent to cross with CMS line Quan 5A in spring 2007 to develop a new rice CMS line, Wutian A, after several backcrossing, observations, and selections for further breeding purpose.

  Result  The newly bred high-quality, early-maturing Wutian A was certified by Fujian Crop Variety Evaluation Committee in 2019 (Certificate No. 20190047). It was stable on male sterility, 100% on plant sterility, 99.99% on pollen sterility, high on outcrossing, and 64.77% on stigma exposure. The rice had the desirable quality with grains that were 66.0% unbroken, 6.7 mm long and 3.4 on length/width ratio, 4% of chalky appearance and 0.6% on chalkiness reading, 23.8% in amylose content, and Grade A on transparency, 7.0 on alkali spreading value, and 50 mm on gel consistency after cooking. Among those characteristics, the non-breakage, chalkiness, transparency and alkali spreading value were top rated for edible Indica rice on quality according to the standards set forth by the Quality of Edible Rice Variety. Whereas, the amylose content and gel consistency could be upgraded with improvements. Like Tianfeng A, Wutian A had a 66 d sowing-to-heading maturation period and strong combining ability. Using Wutian A as the female parent to cross R713 as the male parent, an elite hybrid combination, Wutian A/R713, was bred and certified by Fujian Crop Variety Evaluation Committee in 2019 (Certificate No. 20190035).

  Conclusion  Wutian A, a new CMS cultivar with stable male sterility, high crossing rate, desirable grain quality, early maturation, and strong combining ability, was considered an excellent cultivar for breeding new varieties of 3-line combination hybrid rice.