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:
R01-4787) yielded 100% of the commercial check averaged over 2011 and 2012 Arkansas combined data. In 2012 USDA Preliminary MG V Test, R08-3119 yielded 55.0 bu/a, which was equivalent to 100% of check average (AG 5606, AG 5632RR2Y, 5002T, Osage and AG 5831RR2Y). R08-3119 is a MG 5.7 line with resistance to lodging and shattering. This line is being considered for release. A total of 44 high-yielding, 25 to 50% PI-derived lines, were grouped into two final tests (PDF-1 and PDF-2) and both of the tests were evaluated at three locations in Arkansas (Pinetree, Stuttgart, and Rohwer, AR). Rohwer were not included in the final data analysis because of poor stands there. On average, 19 out of the 44 advanced lines yielded statistically the same (p=0.05) as the mean of the three checks (70.1 bu/a), with a range from 65.4 to 73.6 bu/a, representing 93 to 105% of the check average. Eleven of these 19 lines had yields equivalent to the best check AG 5606. Eight of the 19 lines are 50%-PI derived and eleven are 25%-PI derived. R10-4892 (5002T x R01-3474F), R10-5595 and R10-5594 (R01-3474F x R02-3263RR) were numerically higher in yields than the best check (AG 5606).