Desarrollo de poblcaciones de arroz en Argentina

Because of Argentina's geographical location, rice is cultivated only once a year. The two major production areas are the northern region, which has a subtropical to temperate climate, and the temperate-climate southern region. Genetic improvement of rice began in the 1940s with the selection of introduced materials. Population improvement by recurrent selection began to be used in 1996 as a way of broadening the crop's genetic variability. Populations PCT-6, PCT-7, and PCT-8 were introduced and characterized. Population PCT-8 adapted the most readily to our conditions. All three populations went through recombination cycles. From populations PCT-6 and PCT-7, which had not adapted well, two more populations were created to obtain fixed lines: one with a narrow genetic base (PARG- I/0/0/0) and the other with a broad genetic base (PARG-2/0/0/0). Population PARG-3/0/0/0 was derived from the introduction on new germplasm into population PCT-8/0/0/2. Fertile plants were derived to develop fixed lines from the original populations. Of these derived lines, 94 are to be evaluated in 1999/2000. Population PQUI-1, from Chile, was introduced in 1998 to study its adaptability to the southern rice-producing region. The paper also describes future plans for the next stages in rice population improvement for Argentina. (Résumé d'auteur