Respuesta a la seleccion y a ciclos e recombinacion en la poblacion de arroz (Oryza staiva) de secano PCT-4

CIAT/CIRAD projects have phased out conventional and concentrate on broadening the genetic base of upland rice. Using a recessive male-sterile gone (ms) from a mutant of IR36, the development of rice population was eased and were enhanced using the recurrent selection-breeding method. The present story evaluate and compare the performance of agronomic traits of the upland rice population PCT-4 to one cycle of recurrent selection for acid soils and three cycles of recombination one before selection and two cicles after selection. The traits evaluated in two environments (300 and 3000 kg/ha cal dolomitic) were tolerance to acid soil condition; flowering time; plant height; grain yield and components yield. One selection cycle doesn't permit significant genetic progress. This was to expect as recurrent selection method is a gradual and cyclic process for the genetic enhancement of polygenic traits, wich is the case of the traits evaluated. Open recombination before and after one cycle of recurrent selection doesn't always produce positive effects for some of the traits evaluated. We recommend the use of only one recombination after the selection cycle. This allows speeding-up the next cycle of recurrent selection. (Résumé d'auteur