UPLAND RICE COMPOSITE POPULATION BREEDING AND SELECTION

Since 1996, the collaborative project between CIRAD(Agricultural Research Centre for International Development)and CIAT (Centro Internacional de Agricultura Tropical) hasgradually phased out intra-specific tropical japonica conventionalcrossbreeding activities and concentrated on rice genetic basebroadening. The development and enhancement by recurrentselection of upland rice composite populations are the newbreeding strategies. Using a recessive male-sterile gene (ms), thedevelopment of rice population was made easier. In Colombia,upland basic composite populations were enhanced using tworecurrent selection-breeding methods: mass recurrent selectionand S2 progenies evaluation. At each enhancement cycle, fertileplants are selected for the development of segregating lines andprogeny selection using the conventional pedigree method. Themost advanced lines are evaluated in yield trials by the projectand in collaboration with the Colombian research organization –Corpoica Regional 8, in Villavicencio, Colombia. Promising lineshaving good adaptation to acid soils were identified. One promisingline, extracted from the first cycle of recurrent selection of thecomposite population PCT-4, shows a higher yield potentialwith the same earliness of the best commercial check (Línea 30),developed by conventional crossbreeding.