Breeding temperate japonica rice MS11 for the tropics

There is an increasing number of Japonica rice consumers in Asian countries, particularly in the tropics. Japonica cultivars command a higher price than local Indica rice varieties. The temperate country-bred Japonica cultivars, such as the late-maturing varieties from Korea and Japan, show very low adaptability under tropical conditions as they are photoperiod- and thermosensitive varieties. There is a need to develop temperate Japonica cultivars adapted to tropical conditions, especially in high elevated areas for cultivar diversification and increased rice production. Through the Germplasm Utilization for Value Added (GUVA) breeding program of the International Rice Research Institute, with INGER,RDA, and PhilRice as collaborating partners, MS11/IRRI 142 was developed. The objective is to produce a variety that is well-adapted to tropical conditions, with high yield, distinct, distinct grain quality characteristics such as medium shattering tendency, resistance to pest and diseases, and tolerance for cold stress. Varieties from the Republic of Korea were collected to develop the lines. In the 1993 wet season, a cross between Jimmibyeo and Cheolweon 46 was made to produce F1 seeds (IR68333). The five succeeding generations (IR68333-R-R-B-22) and four-season yield trials were done at IRRI. Three season multilocation trials from 2001 wet season to 2002 wet season likewise evaluated varieties at different test locations:PhilRice-Maligaya, Batac, UPLB, and IRRI.MS11 yielded an average of 4.5t/ha, it is early maturing, have resistance to blast and intermediate resistance to bacterial leaf blight and tungro,very good milling potential, and excellent eating quality. The breeding program has sucessfully released its first variety (NSIC Rc170/MS11) in 2008 and this has been promoted since 2005 in different provinces of the Philippines (e.g., Bohol, Palawan, and Aurora) and among collaborators in Costa Rica and Cambodia. Moreover, marker-assisted selection must be considered to further develop cultivars ideal for different stress environments and to identify genes that can confer traits for tropical adaptation.