Title: Contributions of plant introductions to the ancestry of current U.S. peanut cultivars Authors
|Isleib, Tom -|
Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2013
Publication Date: July 11, 2013
Citation: Isleib, T., Barkley, N.L. 2013. Contributions of plant introductions to the ancestry of current U.S. peanut cultivars. American Peanut Research and Education Society Abstracts. Paper No. 58. Technical Abstract: Plant introductions (PIs) have been used in peanut (Arachis hypogaea L.) improvement in the U.S.A. since the inception of peanut breeding there in the 1930s. One might think that the era of screening collections of PIs for pest resistances or other economically important traits then crossing selected PIs with existing cultivars was over and that breeders would now mark economically important segments of chromosomes for incorporation into new cultivars, incorporate known DNA sequences into genomes or employ directed mutation of existing cultivars to produce new improved lines. An effort was made to ascertain the proportion of ancestry of modern US peanut cultivars that was derived from PIs. The Association of Official Seed Certifying Organizations (AOSCA) maintains a record of certified acreage of all peanut cultivars in the U.S.A., an approximate indicator of which cultivars will be planted in which proportionate areas in the following year. The 2011 record was consulted to determine the distribution of cultivars in U.S. production regions for 2012. Pedigrees of lines used were traced to PIs and previously existing cultivars to determine the contributions of PIs to the ancestries of existing cultivars, assuming the contribution of each parent to be 50% in their offspring. The contribution of a given PI to the 2012 crop was estimated as the sum of cross products of the percentage of the crop occupied by a cultivar times the ancestral contribution of the PI to that cultivar. Overall, PIs contributed 20.6% of the ancestry of cultivars grown in 2012, 22.5% of the ancestry of cultivars of the runner market type (occupying 77.2% of the total acreage), 12.0% of the ancestry of cultivars of the virginia market type (occupying 20.5% of the total acreage), 14.4% of the ancestry of cultivars of the spanish market type (occupying 1.9% of the total acreage), and 100.0% of the ancestry of cultivars of the valencia market type (occupying 0.5% of the total acreage). PI 203396, the source of TSWV resistance in Southern Runner, Georgia Green, and C-99R, was the PI most commonly found in the ancestry of all cultivars (16.1% of all U.S. acreage). This PI which was collected in Brazil contributed critical resistance genes in many runner market type cultivars developed from the Universities of Georgia and Florida. PI 121067 was a distant second (1.0% of all U.S. acreage), figuring most prominently in the ancestry of virginia-type cultivars from NCSU. PI 109839 was third (0.7% of all acreage), occurring through runner-type cultivars from Texas AgriLife Research. A substantial and important part of the ancestry of current U.S. peanut cultivars could be ascribed to PIs that are maintained in the USDA-ARS collection at Griffin, GA.