Molecular Tagging Of Srf,a Gene Conferring Sethoxydim Resistance In Foxtail Millet (Setaria Italica (L.) Beauv.)

Breeding and adequately using herbicide resistant varieties in agriculture production appears to be the most effective and economical ways to control weeds and improve yields. Therefore, it will greatly promote the herbicide resistance breeding to study the molecular tagging of herbicide resistance gene Srf in foxtail millet. In this paper, specific polymerase chain reaction (PCR) and amplified fragment length polymorphism (AFLP) techniques were used to screen molecular markers linked to the herbicide resistance gene Srf of foxtail millet, which will facilitate gaining the gene Srf by map-based cloning. And the optimum reaction procedures of specific PCR and AFLP were evaluated, respectively. The main results were as follows: 1. The AFLP analysis was conducted in the two DNA pools, one is from F2 plants resistant to Sethoxydim and the other from the susceptible, which were set up by bulked segregate analysis (BSA) in foxtail millet. Using two restriction enzymes MseI and EcoPJ, and silver-staining in AFLP technique, 22 out of the 330 pairs of randomly selected primers amplified the polymorphic bands. However, only two pairs of primers (M551E14, M55/E15) showed the same discriminating results in replications. Primer M55/E15 produces 284 bp (APi284) fragment and primer M55/E14 350 bp (AP2350) fragment linked to gene Srf The polymorphic bands AP 1284 and AP2350 were found linked to the Srf locus on the same side with the genetic distance of 7.350cM and 3.593cM ,respectively, and 3757cM between the two markers. The AFLP markers would be facilitate the selection on the herbicide resistance lines in foxtail millet. Also the optimum system and procedure of AFLP were discussed in this study. 2. Of ten pairs of specific PCR primers, each primer could amplified a band about 1kb in herbicide resistance parent, susceptible parent and F2 DNA pools. But - 47 - no polymorphic band was found. However, through the screening of these primers, the optimum system and procedure of specific PCR were established in foxtail millet, which could be a reference to the similar study in the future.