1a. Objectives (from AD-416):
Our objective is to identify and utilize exotic germplasm to improve U.S. soybean productivity. We will deliver 1) high yielding lines derived from exotic germplasm that are available to all U.S. soybean breeders developing new cultivars, 2) quantitative trait loci (QTL) affecting yield with the positive allele derived from exotic germplasm and the DNA markers associated with these loci, and 3) lines derived from exotic germplasm that will improve the yield and seed quality in the Early Planting Production System of the mid-south.
1b. Approach (from AD-416):
High-yielding experimental lines will be developed from exotic germplasm to expand the genetic base and accelerate the rate of yield improvement of soybean production in the U.S. This breeding project will use over 150 soybean introductions and many experimental lines derived from these introductions in past USB projects. These introductions include modern Asian varieties that are unrelated to U.S. cultivars, diverse primitive varieties that predate scientific plant breeding, and wild soybean. The number of exotic lines that we are using exceeds the total number of all the ancestral lines, regardless of the size of their contribution, of all of the current varieties grown in the U.S. Our projects are located in all major soybean-growing regions of the U.S. so that new genes for increasing yield from exotic germplasm will be accessible to soybean breeders and eventually soybean farmers in every soybean-producing state. We will also be testing exotic germplasm and lines derived from exotic germplasm in the Early Planting Production System of the mid-south to select for high yield and improved germination rates in the harvested seeds. Concurrently with developing high yielding experimental lines, we are developing sets of lines (mapping populations) that will allow us to begin the process of identifying specific genes (quantitative trait loci, QTL) from exotic germplasm that can increase yield of commercial varieties and then to confirm those QTL in independent populations.
3. Progress Report:
We made available for distribution to all public soybean breeders 21 heterogeneous inbred populations in maturity groups II, III and IV that were derived from exotic germplasm and selected for high yield. These lines were derived from 24 exotic parents. Seeds were sent to 8 public soybean breeders. In the 2011 Uniform Preliminary IIB Test - Northern Region, the yield of our six entries ranged from 90 to 96% of the yield of the highest yielding check. By pedigree, these lines ranged from 12 to 63% exotic germplasm. The donor parent of the line with only 12% exotic germplasm was a wild soybean accession and that line yielded 94% of the best check. This was one of only two lines, both from our program, derived from wild soybean in all of the entries of the Uniform Tests. In the 2011 Uniform III Test - Northern Region, the yield of both of our entries was 96% of the yield of the highest yielding check. One of these lines also had 12% of its pedigree derived from wild soybean and the other line was 50% exotic germplasm by pedigree. In the 2011 Uniform Preliminary IIIB Test - Northern Region, the yield of our eight entries ranged from 87 to 96% of the yield of the highest yielding check. By pedigree, these lines ranged from 25 to 87% exotic germplasm. In the 2011 Uniform Preliminary IV Test - Northern Region, the yield of our five entries ranged from 88 to 95% of the yield of the highest yielding check. By pedigree, these lines ranged from 25 to 50% exotic germplasm. In 2011 in cooperative tests with 6 soybean breeding companies, we tested 258 experimental lines in 9 tests at between 7 and 18 locations per test. These lines were derived from 61 exotic soybean accessions. We identified 30 lines that numerically exceeded the yield of the best commercial variety included in each test. The best lines exceeded the yield of best commercial variety in the test by 6 bu/a. The pedigrees of these lines ranged from 12 to 100% exotic germplasm and the highest yielding lines had pedigrees with the same range of exotic germplasm. Activities of this project are monitored through quarterly reports, an annual planning meeting, and periodic phone calls and e-mails.