Marker-assisted selection for the rice blast resistance gene Pi-ar in a backcross population
Leila Garcês de Araújo, Anne Sitarama Prabhu, Pedro Antonio Arraes Pereira, and Gisele Barata da Silva
A doubled-haploid (DH) population, obtained by anther culture of F1 plants from a cross between a highly susceptible rice cultivar Lijiangxintuanheigu and the resistant somaclone (SC09), of the cultivar Araguaia, was used to identify RAPD markers linked to the blast resistance gene Pi-ar. The 86 DH plants, inoculated with the race IB-9 of Magnaporthe oryzae, segregated in 1:1 ratio of resistant and susceptible plants. Of the 67 primers used 31 produced DNA profiles that differentiated resistant and susceptible bulks as well as the parental cultivars. The resistance gene was found linked to the primer OPS162072 (‘AGGGGGTTCC’) at a distance of 3.6 cM. The selection efficiency of this primer was assessed in a BC3 F1 population derived from another cross between a susceptible cultivar IAC 201 and SC09. The marker OPS16 showed efficiency of 86.9%, when six resistant and two susceptible plants were considered as negatives in RAPD analysis.