Location: Crop Genetics and Breeding Research
2019 Annual Report
Objectives
Objective 1: Identify and characterize genes/Quantitative Trait Locus (QTLs) controlling resistance to major diseases (leaf spot, white mold, rhizoctonia limb rot, and nematodes) and drought stress, and use the information in marker-assisted breeding to develop improved high oleic (oleic/linoleic fatty acid ratio) peanut cultivars or germplasm with tolerance to biotic and abiotic stresses.
Sub-objective 1.A.: Conduct phenotypic evaluations of recombinant inbred line (RIL) populations to aid in the identification and characterization of genes/QTLs controlling resistance/tolerance to biotic and abiotic stresses.
Sub-objective 1.B.: Develop improved high oleic peanut cultivars or germplasm with resistance to nematodes and improved resistance to leaf spot.
Sub-objective 1.C.: Develop high oleic peanut germplasm with improved drought tolerance and reduced preharvest aflatoxin contamination (PAC).
Approach
1.A. Sixteen structured recombinant inbred line (RIL) populations were developed using parents that were selected to maximize genetic diversity while meeting practical breeding objectives. In-depth phenotyping and genotyping of the populations will be conducted to identify genetic markers that can be used in peanut cultivar development.
1.B. Breeding populations will be developed by hybridizing cultivars with high oleic acid with high yielding breeding lines with resistance to the peanut root-knot nematode and/or resistance to leaf spot. Marker assisted selection will be utilized to select early generation progeny that are homozygous for the desired characteristics (high oleic, nematode resistance, and/or leaf spot resistance). Selections in later generations will focus on field resistance to tomato spotted wilt virus, high yield, and other agronomic characteristics.
1.C. Breeding populations will be developed by hybridizing high-yielding, high-oleic cultivars with sources of resistance to preharvest aflatoxin contamination and sources of resistance to drought. These populations will be evaluated under field conditions with drought and heat stress imposed by covering the entire test area with a mobile greenhouse. Aflatoxin contamination of the subsequent yield will be determined using the immunoaffinity column fluorometer method. Progeny will be selected based on relatively low aflatoxin and/or relatively high pod yields.
Progress Report
Crosses were made to combine resistance to biotic and abiotic stresses with high yield, good grade, and high oleic fatty acid content. Populations were advanced to a more inbred state when marker assisted selection (MAS) was used to identify individuals that will breed true for high oleic fatty acid content and/or nematode resistance and/or leaf spot resistance. Progeny from these individuals are then evaluated for resistance to other biotic and/or abiotic stresses, yield, and other agronomic charateristics. One recombinant inbred line (RIL) population (Tifrunner x NC 3033) was phenotyped for resistance to white mold using a replicated field study. Quantitative trait loci (QTLs) for resistance to white mold were identified.
Accomplishments
1. Identification of fenetic markers for resistance to leaf spot in peanut. Early and late leaf spot are the major foliar diseases of peanut and cost the U.S. peanut industry over $50 million annually. The development of resistant varieties is a sustainable solution to reduce these costs. Genetic markers linked to resistant genes can be used in marker assisted selection (MAS) to speed the development of resistant varieties. The objective of this study was to genotype and phenotype a segregating population of peanut to attempt to identify genetic markers linked to resistant genes. ARS researchers in Tifton, Georgia, identified three genetic markers for resistance to late leaf spot, and three different genetic markers were identified for resistance to early leaf spot. These markers can be used to develop peanut varieties with resistance to leaf spot disease.
Review Publications
Bertioli, D.J., Jenkins, J., Clevenger, J., Dudchenko, O., Gao, D., Seijo, G., Leal-Bertioli, S., Ren, L., Farmer, A., Pandey, M., Samoluk, S.S., Abernathy, B., Agarwal, G., Ballen-Taborda, C., Cameron, C., Campbell, J., Chavarro, C., Chitikineni, A., Chu, Y., Dash, S., El Baidouri, M., Guo, B., Huang, W., Kim, K.D., Korani, W., Lanciano, S., Lui, C.G., Mirouze, M., Moretzsohn, M.C., Pham, M., Shin, J.H., Shirasawa, K., Sinharoy, S., Sreedasyam, A., Weeks, N.T., Zhang, X., Zheng, Z., Sun, Z., Froenicke, L., Aiden, E.L., Michelmore, R., Varshney, R.K., Holbrook Jr, C.C., Cannon, E.K., Scheffler, B.E., Grimwwood, J., Ozias-Akins, P., Cannon, S.B., Jackson, S.A., Schmutz, J. 2019. The genome sequence of segmental allotetraploid peanut Arachis hypogaea. Nature Genetics. 51:877-884. https://doi.org/10.1038/s41588-019-0405-z.
Chu, Y., Chee, P., Culbreath, A.K., Isleib, T.B., Holbrook Jr, C.C., Ozias-Akins, P. 2019. Major QTLs for resistance to early and late leaf spot diseases are identified on chromosomes 3 and 5 in peanut (Arachis hypogaea). Frontiers in Plant Science. 10:1-13.
Chu, Y., Holbrook Jr, C.C., Isleib, T.G., Burow, M., Culbreath, A.K., Tillman, B., Chen, J., Clevenger, J., Ozias-Akins, P. 2018. Phenotyping and genotyping parents of sixteen recombinant inbred peanut populations. Peanut Science. 45:1-11.
Korani, W., Chu, Y., Holbrook Jr, C.C., Ozias-Akins, P. 2018. Insight into genes regulating postharvest aflatoxin contamination of tetraploid peanut from transcriptional profiling. Genetics. 209:143-156.
Songsri, P., Jogloy, S., Holbrook Jr, C.C., Puangbut, D. 2019. Determination of lethal dose and effect of gamma rays on growth and tuber yield of Jerusalem artichoke mutant. SABRAO J. of Breeding and Genetics. 51:1-11.
Yuan, W., Holbrook Jr, C.C., Chu, Y., Ozias-Akins, P., Dickson, D.W. 2018. Influence of temperature on susceptibility of cvs. Tifguard and Georgia-06G peanut to Meloidogyne arenaria. Journal of Nematology. 50:33-40.
