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:
In Preliminary IVS early test, S10-2635 exceeded the yield of 2 of 3 check varieties. Average over two years, S09-9943 was the highest yielding entry in IVS test exceeding the yield of AG 4703 by 1.3 bu/A. S09-13185 had the highest yield averaged over 2011 and 2012 in the maturity group V test yielding 0.4 bu/A more than Osage. S10-2635RR2 Roundup Ready 2 line with 13% PI 427099, PI 445830 and 4.2 maturity has been tested two years in southeast Missouri and it has averaged 3 Bu/A more than AG4232 (63.9 Bu/A), a popular Roundup 2 line of similar maturity. In the 2012 Southern Regional Uniform Preliminary early group IV test across nine sites S10-2635RR2Y averaged 2.6 Bu/A more than AG4232 (68.7 Bu/A). S09-9943 was released as a cultivar. It has 35% of its background derived from LG04-5196 with PI 253665D, PI 283331, PI 391594, PI 437851A in its pedigree. It is a conventional line with tolerance to sulfonylurea herbicides. S09-9943 has yielded equal to high yielding check AG4703 in 13 southeast Missouri tests, 1.8 Bu/A more in 9 Southern Regional Preliminary tests, 2012 and 1.3 Bu/A in 8 southern diversity IV early trials, 2011-12. S09-13185 with 13% of its background derived from PI416937 is mid-group V maturity with resistance to race 1 and 3 of soybean cyst nematode and frogeye leaf spot and tolerance to chloride. It also has averaged 37.7% in protein content vs. 35.0% for 5002T. In 13 southeast Missouri test in 2010-12; seven tests in the regional group V quality traits test in 2012; and in eight tests in the 2012 USB Diversity V test in 2012; S09-13185 was equal to or as much as 1.5 Bu/A higher yielding than RR or conventional checks of similar maturity.