Maintain Line Breeding in Hybrid Ricce.

Breeding Maintainer Lines for Hybrid Rice

Zongbu Yan¹, Christopher W. Deren¹, and Wengui Yan²

¹Rice Research and Extension Center, University of Arkansas, 2900 Highway 130 E., Stuttgart, AR 72160  

        ² USDA-ARS Dale Bumpers National Rice Research Center, 2890 Highway 130 E., Stuttgart, AR 72160   

     Maintainer lines are a component of 3-line hybrid rice production, necessary to perpetuate the male-sterile (MS) line.  In practice, it is often the maintainer that is bred with an array of desirable traits, then male-sterility is transferred in through several backcrosses with the new maintainer to establish the male-sterile line. Twenty rice accessions from the USDA/ARS rice germplasm collection were used in developing new maintainer lines at University of Arkansas Rice research Center.  There were 3 from Korea, 5 from China, 4 from IRRI, 2 from Japan, and 6 from the US.  One hundred crosses of these lines in various combinations were then observed in segregating populations (F2 to F5) under greenhouse and field conditions.  Particular emphasis was placed on traits such as stigma exertion, flowering date, and panicle position as well as the usual array of agronomic and grain quality traits.  Thirty lines were finally selected out of the F5 generation with desirable phenotypes for backcrossing with male-sterile lines and subsequent testing for combining ability with chosen restorers.  Several hybrids resulting from new MS and maintainer lines have performed well in regional yield tests.