Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2002
Publication Date: 9/1/2003
Citation: CHARLSON, D.V., CIANZIO, S.R., SHOEMAKER, R.C. ASSOCIATING SSR MARKERS WITH SOYBEAN RESISTANCE TO IRON CHLOROSIS. JOURNAL OF PLANT NUTRITION. 2003. v. 26. p. 2267-2276. Interpretive Summary: Iron deficiency chlorosis causes millions of dollars in lost soybean production each year. Some progress in breeding more efficient soybean lines has been made but selection for improved lines is difficult because of the strong effect of the environment. In this paper the authors report the use of molecular markers to `pre-select' lines prior to planting in the field, thus increasing the efficiency of selecting improved lines. They showed that they could increase the frequency of `superior' lines in the field from 13% (without preselection) to as much as 27% with preselection. This approach can be used by plant breeders to increase the probability of finding improved plants in the field and can decrease the cost of the field component of breeding programs.
Technical Abstract: Iron deficiency chlorosis (IDC) causes soybean yield loss to growers when certain varieties are planted on calcareous soils. The importance of environment on chlorosis expression impedes progress in improving IDC resistance. Breeders could use molecular marker-assisted selection (MAS), an environment-independent tool, to improve soybeans¿ resistance to IDC. Our objective was to determine the efficiency of simple sequence repeat (SSR) markers in selecting for IDC resistance in soybean. A breeding population differing in IDC resistance and yield potential was advanced to the F2 and F2:4 generations. Foliar chlorosis data were recorded for parents and F2:4 lines in replicated field tests planted on calcareous soils at two Iowa locations in 2000 and 2001. Genotypic data were obtained on individual F2 plants, and association between chlorosis scores and allele segregation was tested by single-factor analysis of variance using 2001 data. Three SSR markers were associated (P¿0.1) with chlorosis scores at each location; however, different markers were identified at each location. In addition, two SSR markers associated with chlorosis were examined for their efficacy in improving breeding efficiency. Preliminary data presented herein demonstrates the importance of environment on expression of this soil-stress factor and the potential of using SSR markers as an environment-independent selection tool for breeding for IDC resistance in soybean.