Advanced tools for rice breeding : population breeding using recurrent selection in Chile

Latin America rice production is concentrated in tropical and sub-tropical regions using indica. In this scope, Chile is an exception. Rice growing area is located between 34° and 36°36' South Latitude with temperate climate, and rice is Japonica. Commercial rice cropping started in the 30¿s reaching about 27,000 ha. Average consumption is 10 Kg per capita per year. The INIA breeding project aims at enhancing targeted complex traits like cold tolerance, grain yield and quality. Through traditional breeding, progress has been made and varieties released to farmers. Average yield increased from 2.5 t/ha to 5.2 t/ha. To step further and broaden the existing genetic base, population breeding using recurrent selection was implemented. Population breeding aims at, using rice genetic variability (number of parents involved), gathering and exploiting bio-diversity in targeted gene pools. The japonica GPIRAT-10 population, with genetic variability from Europe and USA, developed by CIRAD for Mediterranean condition was evaluated in Chile. It showed potential genetic background adaptation. From GPIRAT-10, INIA and CIRAD/CIAT developed the site-specific japonica population PQUI-1, adapting the genetic base of GPIRAT-10 through introduction of elite lines from Chile. PQUI-1 is segregating for a recessive mal-sterile gene coming from GPIRAT-10, easing natural recombination at field condition. PQUI-1 was selected in two climatic zones (North and South of the rice growing area). Recurrent selection started for cold tolerance at early and flowering stage. Promising lines from the basic and enhanced populations are being developed. Evaluation of lines from traditional and population breeding is in progress. (Résumé d'auteur)