W679 Recombinant Inbreds for Sugar Beet: Insights from Developing First Generation Resources

Date: Saturday, January 14, 2012
Time: 1:50 PM
Room: Pacific Salon 2
J. Mitchell McGrath , USDA-ARS Sugarbeet & Bean Research Unit, East Lansing, MI
Sugar beet is an outcrossing species facilitated by a complex system of self-incompatibility. By deploying the dominant self-fertily gene, self-fertile F1 hybrids can be made and their progeny can be selfed to fixation over successive gererations. Such populations could have broader utility for the beet and plant science communities, for instance inbreds provide a genetically uniform population whereby the molecular basis of phenotypes may better be understood. Over 1,000 self-fertile hybrids have been made in East Lansing, and over 1,400 F2 seedlots have been generated. The process, implications, and preliminary results of inbreeding beets from the F2 to the F6 is the focus of this presentation. Beet pollen is wind-blown, thus potection from out-crossing by bagging the flower stalk is needed. However, even without bagging, out-crossing rates of 20% or less among self-fertile materials were seen in the greenhouse. Beet flowers are small and hybridization is facilitated by use of male-sterility, which impacts inbreeding success in following generations in an as yet unpredicatable manner. None-the-less, ~4,500 F3 seedlots, ~2,200 F4 seedlots, ~1,400 F4, ~1,400 F5, and ~1,600 F6 seedlots have been generated. The source materials were a highly diverse collection of crop type (sugar, table, chard, fodder, wild) chosen for some aspect that would shed light on inheritance of major traits needed by sugar beet growers. Field agronomics of the most advanced Recombinant Inbred Lines (RIL) shows a wide range of phenotypic values, and these genetics should now be relatively straightforward to dissect.