COMPARISON OF RICE LINES DERIVED THROUGH ANTHER CULTURE AND THE PEDIGREE METHOD IN RELATION TO BLAST (PYRICULARIA-GRISEA SACC) RESISTANCE

Crosses were made between Fanny (highly susceptible to blast) and 11 c ultivars differing in blast resistance. Using the pedigree method (PM) segregating generations were evaluated and selected for blast resista nce. Via anther culture (AC), doubled-haploids were obtained from F-1 plants and from F-2 blast-susceptible plants. Pedigree and anther cult ure-derived lines were planted together and evaluated for blast resist ance under rainfed conditions at the Santa Rosa Experiment Station, Vi llavicencio, Colombia. The principal objective was to compare PM and A C in terms of their efficiency in producing rice lines resistant to bl ast. Results of a stratified analysis showed an association between me thod and blast resistance. Results of the legit-model analysis showed that AC produced a significantly (P=0.0001) higher proportion of lines with initial blast resistance (leaf- and neck-blast reaction less tha n or equal to 4) than did PM across all cross types. Stable blast resi stance was assessed based on field performance over 3 years. AC was su perior to PM in generating stable resistance for only some cross types . Consequently, with a few exceptions, AC can be used as effectively a s PM to develop rice cultivars resistant to blast, with savings in tim e and labor. Additionally, blast-resistant lines were obtained either by the pedigree method or by anther culture from crosses between blast -susceptible cultivars (Fanny/CICA4 and Fanny/Colombia1). This exclude s somaclonal variation as a possible mechanism responsible for this re sistance and suggests that a recombination of minor genes could have o ccurred and was fixed through either method. However, the stability of the resistance was greater in pedigree-derived lines. The implication s of these findings for rice blast-resistance breeding are discussed.