Identification of rapd marker linked to blast resistance gene in a somaclone of rice cultivar Araguaia

Abstract

The gene Pi-ar confers resistance to Pyricularia grisea race IB-45 in a somaclone derived from immature panicles of the susceptible rice (Oryza sativa) cultivar Araguaia. RAPD technique was used to identify molecular markers linked to this gene utilizing bulked segregant analysis. Initially, the two parental DNAs from the resistant donor SC09 and 'Araguaia' were analyzed using random primers. Of the 240 primers tested, 203 produced amplification products. The two parental DNAs along with the resistant and susceptible bulks of F2 population were screened using 48 primers that differentiated resistant and susceptible parents. Even though eight primers differentiated the resistant bulk from the susceptible bulk, as well as somaclone SC09 and 'Araguaia', only one primer, OPC02 ('GTGAGGCGTC'), was found to be tightly linked (1.7cM) to the resistance gene of somaclone SC09.

Search for a Microsatellite Marker Linked with Resistance Gene to <i>Xanthomonas axonopodis</i> pv. <i>malvacearum</i> in Brazilian Cotton

“…Invariably, the artificial inoculations with bacteria give a margin for misinterpretation of the results because of the inconsistent reactions influenced by unsuccessful inoculations especially under field conditions [4]. Marker assisted selection (MAS) is being advocated to aid selection of resistant plants in early generations in some plant species [5][6][7][8][9][10][11][12]. The MAS technique allows us to identify the presence of resistance gene(s) in segregating populations of early generations within a few days and avoids repeated inoculations under field conditions.…”