Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2016
Publication Date: 8/4/2016
Citation: Jia, Y., Berger, G., Mcclung, A.M. 2016. Registration of 42 blast resistant medium grain rice genetic stocks with suitable agronomic, yield, milling yield, and grain characteristics. Journal of Plant Registrations. doi:10.3198/jpr2016.03.0015crgs.
Interpretive Summary: Blast disease of rice is one of the major constraints for rice production in the southern USA and worldwide. Without blast resistance, fungicides are used to protect the yield and quality of the rice crop. Although the southern USA primarily produces long grain rice, there is a market demand for premium quality medium grain rice that is commonly grown in California. Our objective was to develop medium grain rice genetic stocks that have broad spectrum blast resistance that can be used by breeders to develop new varieties for the medium grain market. We performed backcrossing and crossing with an US adapted blast resistant rice cultivar Katy which carries the major blast resistance gene Pi-ta that provides resistance to all but one of the known races of blast that are commonly found in the southern USA. A total of 42 improved genetic stocks with Pi-ta and suitable agronomic traits, which are highly similar to M202, were developed. From 2013 and 2014, using field plot experiments, we determined that agronomic traits, yield components, seed characteristics, and yield and milling yield were suitable for breeders to use for developing improved medium grain rice germplasm and cultivars. These genetic stocks will help in the development of blast resistant medium grain rice germplasm and cultivars in the southern US and worldwide.
Technical Abstract: Rice blast disease caused by the filamentous ascomycete fungus Magnaporthe oryzae Cav. [Magnaporthe grisea (Herbert) Barr.] is one of the most threatening rice diseases in the southern United States. In the present study, 42 rice (Oryza sativa L.) blast resistant genetic stocks (GSOR102501 to 201542) were developed and released by USDA-Agricultural Research Service Dale Bumpers National Rice Research Center, Stuttgart, AR. The genetic stocks were developed from a cross of ‘M202’ (PI 494105), a medium cultivar with premium grain quality, with the blast resistant long grain rice cultivar ‘Katy’ (PI 527707), followed by 5 generations of backcrossing to the medium grain parent. Two progenies of each of the 22 BC5F1 were genotyped with single sequence repeat (SSR) markers, and evaluated with the blast pathogen to verify the existence of the large blast resistance gene cluster on chromosome 12 inherited from Katy. A total of 42 BC5F2 progenies resistant to blast were grown under field conditions during 2013-2014 at Stuttgart, AR for agronomic and grain quality characterization. Agronomic traits, yield components, seed characteristics, yield and milling quality of 42 lines were highly similar to M202. The genetic stocks should be useful for breeders interested in developing new medium grain varieties with broad spectrum blast resistance.