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ARS Home » Pacific West Area » Pullman, Washington » Grain Legume Genetics Physiology Research » Research » Research Project #423174

Research Project: Genetic Improvement of Cool Season Food Legumes

Location: Grain Legume Genetics Physiology Research

2018 Annual Report

In the United States, pea, lentils and chickpeas are grown primarily in the Pacific Northwest and Northern Plains. Over the past five crop seasons (2007-2012), these crops have been grown on an average of 1,260,000 acres in the US with an average harvest value of over $320 million. These crops also contribute to the success of the US wheat and barley industry by serving as useful rotation crops in small grain production systems. This research project has three objectives that focus on developing new and improved varieties of cool season food legumes (peas, lentils, and chickpeas) and effective integrated disease control strategies for these crops. 1) Develop and release new varieties and germplasm of peas, lentils, and chickpea that have higher seed mineral concentrations; improved host-plant resistance to Aphanomyces root rot, Sclerotinia wilt and Ascochyta blight; and higher yields than existing commercial varieties. 2) Identify genetic markers closely associated with superior yield, optimal plant height for harvest, seed mineral concentration, resistance to Aphanomyces root rot, and improved cold tolerance for autumn-sown peas, and validate their utility for marker-assisted plant breeding. Sub-objective 2A: Identify molecular markers in adapted pea populations that are associated with important traits including concentrations of minerals in seed, resistance to Aphanomyces root rot, and winter hardiness. Sub-objective 2B: Identify molecular markers in adapted chickpea populations that are associated with seed size and early maturity. 3) Develop efficient techniques to screen peas, lentils, and chickpeas for host-plant resistance to Ascochyta blight and Sclerotinia wilt, and characterize genetic and physiological factors responsible for the virulence of these pathogens. Sub-objective 3A: Develop efficient techniques to screen peas, lentils and chickpeas for resistance to Ascochyta blight and Sclerotinia white mold. Sub-objective 3B: Determine genetic factors responsible for pathogenicity of Sclerotinia sclerotiorum using a variety of genetic and genomic tools. Sub-objective 3C: Determine the role of solanapyrone phytotoxins produced by A. rabiei during the development of Ascochyta blight disease in chickpea. This research will result in several products, including new varieties of peas, lentils, and chickpeas along with improved methods for controlling diseases of these crops.

New varieties and germplasm will be developed from pure lines selected from among segregating populations of peas, lentils, and chickpeas. Cyclical hybridization will be conducted to combine favorable alleles for traits of interest. Parental lines will include adapted germplasm, commercial cultivars and accessions from the various international breeding programs. Promising breeding lines will be released as either germplasm or varieties based on a rigorous comparison of their performance relative to that of commercial check varieties. Linkage analysis and the detection of associations between markers and different traits will be done using simple sequence repeats (SSRs), expressed sequence tagged- SSRs, and single nucleotide polymorphisms (SNPs). Pea recombinant inbred line (RIL) populations will be developed from a cross between Aragorn and Kiflica to identify markers associated with seed mineral concentrations. RILs from a cross between the pea cultivars Medora and Melrose will be used to identify markers associated with cold tolerance. Molecular markers associated with seed size and early maturity in chickpea will be detected using a RIL population developed from an interspecific cross between C. arientinum line Flip 90-27 and PI599072 (C. reticulatum). Associations between markers and quantitative trait loci (QTL) conditioning traits of interest will be detected by composite interval mapping. Improved methods will be developed to screen chickpea for reaction to Ascochyta blight. Toxins will be purified from liquid cultures of A. rabiei. Toxins will be adjusted to various concentrations and applied to detached chickpea leaflets. Leaflets treated with water will be used as controls. The speed of lesion development and final lesion size will be used to compare the reactions of different chickpea genotypes. The relationship between field disease scores of the chickpea genotypes and their sensitivity to the toxin will be determined. Studies to develop more efficient methods to screen peas and lentils for reaction to Sclerotinia white mold will initially examine resistant and susceptible materials reported in prior studies. Plants will be grown in the greenhouse and inoculated with agar plugs containing mycelia of S. sclerotiorum. Disease reaction will be scored by measuring the length of the lesion produced by the fungus over different time points. Two approaches will be taken to investigate the genetic factors responsible for pathogenicity and virulence of S. sclerotiorum. One approach will be to use Agrobacterium mediated transformation (AMT) to generate random mutations that will be screened to detect mutants with reduced virulence. The other approach will be to identify genes of S. sclerotiorum that are differentially expressed during the processes of infection and disease development.

Progress Report
This is the final report for this project which terminated in April 2018. Research conducted during the course of this project is being continued and expanded in the new project 2090-21000-034-00D, “Improving Genetic Resources and Disease Management for Cool Season Food Legumes”, which started in April 2018. Please see the report for the new project for additional information. Objective 1: Our first objective supports NP 301, Problem Statement 1A “Superior new crops, varieties, and enhanced germplasm”, and has a primary focus on developing improved germplasm and varieties of peas, lentils, and chickpeas. During the course of this project we developed and released several improved varieties including two new chickpea varieties “Nash” and “Royal”, two new lentil varieties “Morena” and “Avondale”, and a new green pea variety “Hampton”. All of these varieties are commercially licensed and are currently being grown on more than 125,000 acres throughout the U.S. with an annual production value of approximately $50 million in 2017. These new varieties enhance economic opportunities in the rural regions where they are produced and ensure that the U.S. has secure sources of nutritious pulse crops for both domestic consumption and export. Objective 2: Our second objective, which supports NP 301, Problem Statement 1B “Innovative approaches to crop genetic improvement and trait analysis”, focuses on identifying new sources of desirable traits and new methods for accelerating progress in plant breeding. During the course of this project we identified DNA markers that are associated with several important traits including disease resistance in peas and chickpeas, and seed mineral content in peas. These markers are being used by breeders in the U.S. and abroad to rapidly identify plants with desirable traits that can be used as parents to develop more disease resistant and nutritious varieties. We also investigated the use of unmanned aerial systems, commonly known as “drones”, for the remote identification of desirable plants. Our results demonstrate that drones can be used early in the growing season to identify plants that produce high seed yields, which allows us to immediately use these high yielding plants as parents to develop improved varieties that have high yields and improved resistance to diseases and environmental stresses. Objective 3: Our third objective supports NP301, Problem Statement 1B “Innovative approaches to crop genetic improvement and trait analysis”, and NP 303, Problem Statement 2A “Fundamental pathogen biology”, and focuses on developing rapid methods to identify disease resistant plants and improving understanding of how pathogens cause plant diseases. The fungus Sclerotinia is one of the most globally destructive plant diseases, causing white mold disease on over 300 crops across the entire world. We identified 17 genes that are especially active while the fungus is infecting plants. Now we are examining each gene in closer detail to determine its role in disease. Better understanding of how the fungus causes white mold disease can help breeders of hundreds of crops identify new strategies to develop resistant varieties. The great majority of chickpea producers in the U.S. apply chemical treatments to the seed before planting as a primary means of controlling several diseases. We determined that a fungus with resistance to a commonly used seed treatment fungicide was responsible for a seed rot disease of chickpea that has emerged in the Pacific Northwest. Over several years we tested various seed treatments for the ability to control this disease and identified several promising treatments. In particular, we identified the fungicide Ethaboxam as being very effective at disease control. Chickpea growers throughout Idaho and Washington now routinely apply this treatment to control this destructive new disease.

1. New higher yielding lentil variety released. Lentils have been crucial to agricultural production systems and global human nutrition for thousands of years. Over the past 20 years lentil production has increased in the U.S. until currently we are the fourth highest producer of lentils globally. New lentil varieties must be developed that are well adapted to emerging production regions in the U.S. and have seed traits desired by consumers. ARS scientists at Pullman, Washington, developed and released the new lentil variety “2273E”, a small green lentil that typically yields 20 percent more than the variety, Eston, which it is intended to replace. It performs well in all lentil producing regions in the U.S. and will be primarily exported to Europe. This new lentil variety enhances economic opportunities in the rural regions where it is produced and ensures that the U.S. has secure sources of nutritious pulse crops for both domestic consumption and export.

Review Publications
Boydston, R.A., Porter, L.D., Chaves-Cordoba, B., Khot, L., Miklas, P.N. 2018. The impact of tillage on pinto bean cultivar response to drought induced by deficit irrigation. Soil and Tillage Research. 180:63-72.
Kim, W., Park, J., Dugan, F.M., Gang, D., Vandemark, G.J., Peever, T., Chen, W. 2017. Production of the antibiotic secondary metabolite solanapyrone A by the fungal plant pathogen Ascochyta rabiei during fruiting body formation in saprobic growth. Environmental Microbiology. 19(5):1822-1835.
Ma, Y., Coyne, C.J., Main, D., Pavan, S., Sun, S., Zhu, Z., Zong, X., Leitao, J., McGee, R.J. 2017. Development and validation of breeder-friendly KASPar markers for er1, a powdery mildew resistance gene in pea (Pisum sativum L.). Molecular Breeding. 37:151.
Hu, J., Chen, W., McGee, R.J. 2017. Three faba bean (Vicia faba L.) breeding lines appear naturally resistant to Pythium damping-off. Plant Disease Management Reports. 11:V008.
Landry, E.J., Coyne, C.J., Mcgee, R.J., Hu, J. 2017. A modified mass selection scheme for creating winter-hardy faba bean (Vicia faba L.) lines with a broad genetic base. Journal of Euphytica. 213:72.