Preliminary Study On SSR Markers Linked To The Resistance Gene Of MRDV In Maize

The maize was one of three big grain crops in the world, as well as feed and industrial materials. Maize rough dwarf disease was a serious virus disease, caused by the maize rough dwarf virus (MRDV). Recently, due to the frequent occurrence of disease caused massive losses in maize production throughout our country. Exploring and using MRDV disease resistant germplasm resources, establishing an advanced screening technology was the most cost-effective measures for rough dwarf disease resistance. The experiment explored MRDV Inheritance of resistance to disease and related molecular markers and was expected to be the reference to the further study on breeding for disease resistance.The"Qi 319"and"Ye478"was used to construct F1, BC and F2 populations in this study. They were evaluated for their resistance to disease by seedling stage and adult stage in the field assessments. The SSR marker and BSA method were adopted to identify the resistance related genes, and finally the MRDV disease resistance gene linked SSR marker was found. The main results were as follows:①The field identification of the parents and their generations showed that all of"Qi 319", F1 and BC1 populations were resistant. The resistant and susceptible were separated from BC2 and F2 populations. In 189 F2 individuals, there were 147 resistant individuals, and the left were susceptible. The ratio of their resistant plants and the susceptible was about 3:1, and it accorded with theχ_c~2 test (χ_c~2=0.78). In 80 BC2 individuals, there were 45 resistant individuals, and the left were susceptible. The ratio of their resistant plants and the susceptible was about 3:1, and it accorded with theχ_c~2 test (χ_c~2=1.25). It was assumed in this study that the resistance of the maize varieties was controlled by a dominant gene.②88 pairs of SSR primers covering maize genome with 10 pairs of chromosomes were screened by BSA in resistant and susceptible parental DNA pools. And only 39 pairs showed polymorphic. Then by sub-screening in F2 DNA pools with the polymorphic primers, there were only 2 pairs left (bnlg125 and bnlg1064) was obtained. After analysis of the 189 F2 individuals with bnlg125 and bnlg1064 polymorphic primers, the fragment (bnlg125-410) was amplified by PCR with bnlg125 primer linked with resistant gene of MRDV and the genetic distance between them was 5.8 cM.