|PANDEY, MANISH - University Of Georgia|
|QIAO, LIXIAN - University Of Georgia|
|FENG, SUPING - University Of Georgia|
|KHERA, PAWAN - University Of Georgia|
|WANG, HUI - University Of Georgia|
|WANG, JIANPING - University Of Florida|
|Holbrook, Carl - Corley|
|CULBREATH, ALBERT - University Of Georgia|
|VARSHNEY, RAJEEV - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India|
Submitted to: Biomed Central (BMC) Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2014
Publication Date: 12/10/2014
Citation: Pandey, M.K., Wang, M.L., Qiao, L., Feng, S., Khera, P., Wang, H., Tonnis, B.D., Barkley, N.L., Wang, J., Holbrook Jr, C.C., Culbreath, A., Varshney, R.K., Guo, B. 2014. Identification of QTLs associated with oil content and mapping FAD2 genes and their relative contribution to oil quality in peanut (Arachis hypogaea L.). Biomed Central (BMC) Genomics. 15:133.
Interpretive Summary: Oil quality traits of peanut have great impact on peanut market due to profitability and consumers due to several health benefits. FAD2 genes are known to control some of these traits but their position on the peanut genome and their relative contribution towards total phenotypic variance for these quality traits are not studied. This research leads to development of a genetic map with more markers constructed from two crosses, SunOleic 97R × NC94022 and Tifrunner × GT-C20, and identification of 49 M-QTLs and 115 E-QTLs with PVE up to 74.03% and 72.69%, respectively. More importantly this is the first report of estimating PVE of these two FAD2 genes for oleic acid, linoleic acid and O/L ratio in addition to mapping these genes. It is clear that contribution of FAD2B is higher than the FAD2A gene. Thus, the information generated through this study is very useful for marker-assisted selection for peanut oil quality.
Technical Abstract: Improvement of oil quality traits in peanut is the second most important research goal other than yield because of high impact on market and consumers due to profitability and several health benefits. Although FAD genes are known to control some of these traits but their position on the peanut genome and their relative contribution towards total phenotypic variance for these quality traits (total oil content, oleic and linoleic fatty acids, and O/L ratio) is still unknown. Two recombinant inbred line (RIL) mapping populations were used in this study, which were derived from SunOleic 97R × NC94022 and Tifrunner × GT-C20. Total 249 marker loci were mapped and FAD2A (A-genome) and FAD2B (B-genome) were mapped on AhIX and AhV linkage groups, respectively. Further, QTL analysis detected a total of 49 main-effect QTLs (M-QTLs) explaining upto 74.03% phenotypic variance (PVE) and 115 epistatic QTLs (E-QTLs) upto 72.69% PVE for all the four quality traits. Two marker intervals representing mutant alleles FAD2A and FAD2B contributed up to 23.36% and 39.27% phenotypic variance (PVE), respectively for oleic acid; up to 26.07% and 41.21%, respectively for linoleic acid; and up to 10.84% and 30.45 – 74.03%, respectively for O/L ratio, respectively. All the interactions detected through QTLNetwork were two-locus while GMM 98 interactions were among three loci. The phenotypic effect of E-QTLs detected through QTLNetwork showed lower PVE (0.5 - 16.17%) as compared to E-QTLs from GMM (25.82 to 72.69% PVE). In summary, present study identified 49 M-QTLs and 115 E-QTLs with PVE up to 74.03% and 72.69%, respectively. More importantly this is the first report of estimating PVE of these two FAD2 genes for total oil content, oleic acid, linoleic acid and O/L ratio in addition to mapping these genes. It is clear that contribution of FAD2B is higher than the FAD2A gene. Thus, the information generated through present study is very useful for marker-assisted accelerated improvement of peanut oil quality.