Resumen

ARNAO, Erika et al. RECURRENT PARENT GENOME RECOVERY IN A MARKER ASSISTED BACKCROSS BREEDING PROGRAM IN RICE. INCI [online]. 2006, vol.31, n.6, pp.431-436. ISSN 0378-1844.

Rice blast (Pyricularia grisea (Cooke) Sacc.) is one of the most destructive diseases of rice world-wide. The deployment of resistant cultivars is the most effective and economic way for controlling the disease. The backcross breeding is the method most commonly used for incorporating single resistance genes. It is limited by the presence of linkage between the resistance gene and undesirable traits, which may persist even after many generations of backcrossing. Marker assisted selection (MAS) contributes to overcome the main limitation of the backcross breeding, accelerating the recovery of the recurrent parent (RP) genome. The purpose of this study was the recovery of the RP genome in early generations of backcrossing by using molecular markers. Thirty six microsatellites located in the 12 rice chromosomes were evaluated in the parents and the polymorphic ones were evaluated in plants of the BC₂F₂ and BC₃F₁ generations. MAS allowed identification of plants which were 100% similar to the RP for the loci evaluated in both generations of backcrossing. However, the probability of finding those genotypes was greater in BC₃F₁ than in BC₂F₂. Some chromosomal regions were identified as candidates for mapping the resistance gene in chromosomes 4 and 7. The application of MAS on this backcrossing breeding program accelerated the recovery of the RP genome, reducing the number of generations and the time for incorporating resistance to rice blast.

Palabras clave : Microsatélites; Piricularia; Resistencia; SAM.