Recipient Organization
UNIVERSITY OF NEBRASKA
(N/A)
LINCOLN,NE 68583
Performing Department
Panhandle Res & Extension Cntr
Non Technical Summary
The Nebraska Dry Bean Breeding Program continues its involvement in the multistate W-3150 project. I am Vice Chair of this project and lead efforts for its renewal (W_TEMP_4150 'Breeding Phaseolus Beans for Resilience, Sustainable Production, and Enhanced Nutritional Value'). Nebraska project goals are to develop and release improved high-yielding dry bean cultivars/germplasm for western Nebraska to enhance the competitiveness of the Nebraska dry bean industry. Specific objectives include 1.) developing improved high-yielding dry bean cultivars/germplasm for western Nebraska with multiple disease resistance, upright plant architecture, less than 95 days from planting to harvest, and high seed quality, 2.) studying the genetics/mapping the genes responsible for common bacterial blight pv. fuscans resistance and transferring this resistance into elite Nebraska dry bean lines, and 3.) introgressing drought tolerance into elite Nebraska germplasm. These objectives complement those of the W-4150. Methods include: replicated trials across different generations of inbreeding, demonstration plots in growers' fields, disease screening (field and greenhouse trials), collaborative multistate trials, shuttle-breeding (Puerto Rico and Nebraska), and marker assisted selection. Results will be disseminated through industry and scientific publications/presentations including: the Bean Bag newsletter, the Bean Improvement Cooperative meetings/publications, peer-reviewed journals, and Nebraska Dry Bean Growers Association bean days. Summaries of the Dry Bean Drought Nursery and Cooperative Dry Bean Nursery (CDBN) trials will be distributed to collaborators. CDBN and Dry Bean Variety Trial results will be posted on the University of Nebraska-Lincoln Crop Watch website. This work supports efforts to secure external funding from state, national, and international agencies.
Animal Health Component
40%
Research Effort Categories
Basic
50%
Applied
40%
Developmental
10%
Goals / Objectives
Increase productivity and sustainability
Project Methods
Objective 1: Develop improved high-yielding dry bean cultivars/germplasm for western Nebraska with multiple disease resistance, upright plant architecture type, less than 95 days from planting to harvesting, and high-quality seed. Top dry bean lines in early, intermediate, and late generations within several market classes tested previously in replicated trials at Scottsbluff and Mitchell, NE will be continued being evaluated during 2020 and beyond. The pedigree breeding method for multiple crosses and the modified bulk method for single crosses will continue to be used. The 'Good x Good' approach will be used to cross elite adapted Nebraska lines with germplasm from several sources that possess disease resistance, good agronomic traits, earliness, and upright plant architecture. In years 1-5 (2020-2024), multiple traits will be incorporated into elite lines using single, three-way, double, and multiple crosses. Cyclical intercrossing of elite superior lines will also be performed.Demonstration plots of elite great northern and pinto lines will be planted at the PHREC-Scottsbluff (Mother trials) and in growers' fields grower fields in Morrill, Scotts Bluff, and Box Butte counties (Baby Trials) from 2021 to 2025.My dry bean breeding program continues to participate in collaborative multistate bean breeding trials, including the Mid-West Regional Performance (MRPN), Dry Bean Drought Nursery (DBDN), and the national Cooperative Dry Bean Nursery (CDBN) and White Mold Monitor Nursey (WMMN). I continue to serve as the coordinator for the DBDN and CDBN (since 2011).Disease screeningBacterial wilt (BW): A RIL population developed by single seed descent (G18829/Raven; 303 RILs) was screened against a virulent bacterial wilt isolate at the V2 stage. One plant was punctured between the first and second node with a needle dipped into a 48-hour old bacterial culture. Negative controls were used. The plants were evaluated from 7 to 42 days after inoculation using a 1-5 scale, where 1= immune and 5= very susceptible. The overall goal is to determine the genetics of BW resistance and to identify molecular markers that can be used in dry bean breeding programs. A linkage map will be constructed using SNP markers generated by Molecular Inversion Probes (MIPs) and QTL identified for host resistance.Common bacterial blight (CBB) pv. fuscans: Accessions from the U.S. dry bean core collection (424) and CIAT (1700) and great northern and pinto bean cultivars currently grown in western Nebraska will be screened for resistance to CBB in the dry bean breeding greenhouse facilities at the PHREC-Scottsbluff. The accessions will be planted in an augmented block design with each block including GN Nebraska #1 selection 27 and Orion as the resistant and susceptible checks, respectively. When the first trifoliate is fully expanded, three of the four plants in each pot will be inoculated with a bacterial suspension using a multiple needle method. The other will be inoculated with sterile water as a control. The inoculum, a 107 cfu ml-1 bacterial suspension from a Nebraska fuscans isolate. Plants will be evaluated 14-25 days after inoculation using a 1-5 scale, where 1= immune, and 5= very susceptible (CIAT, 1987).Rust: Intermediate and advanced lines will be screened for resistance to rust races 415-1 (41), 4-10 (44), 15-3 (47), 22-6 (49), 31-1 (53), 31-22 (67), and 22-52 (108) at the Beltsville, MD greenhouse facilities. 'Pinto UI 114', 'Aurora' (Ur-3), and 'Weihing' (Ur-3, Ur-6) will be used as very susceptible, intermediate, and resistant checks, respectively. The experimental lines will be replicated two times. Plants will be inoculated at the primary leaf stage using spores of the rust races of interest. Plants will be scored for hypersensitive response or pustule size using a rust evaluation scale that considers pustule size (scale of 1-6) and intensity of infection (Stavely et al., 1993).Bean Common Mosaic Virus (BCMV): The NL3 strain of BCMNV will be used to screen bean lines for resistance to both BCMV and BCMNV. The inoculum will be prepared by grinding 1 g of young BCMNV infected leaves in 5 ml of cold 0.01 M phosphate buffer (pH 7.0). Primary leaves will be inoculated when they have expanded. Response will be evaluated using Kelly's (1997) description of the differential reactions of eight common bean varieties.White mold (WM): Dry bean fields with a previous history of WM will be used for field screening trials, with susceptible pinto cultivar, 'Othello,' planted in spreader rows. WM severity (percent of above ground plant canopy with WM symptoms) will be evaluated at plant maturity. The most resistant advanced lines will be screened in the multi-state WMM dry bean nursery.Molecular markersUse of molecular markers to incorporate and pyramid disease resistance into commercial beans continues. Marker Assisted Selection (MAS) complements traditional breeding methods that screen for disease resistance through all breeding generations. Publicly available molecular markers for resistance to rust, CBB, BCMV and BCMNV, and/or WM will be used to characterize our elite and segregating bean lines and facilitate selection for multiple disease resistance. Intertek SNP platform for MAS will be used. The most promising lines will be used as recurrent parents in our crossing block to develop new hybrid combinations.Objective 2: Study the genetics and map the genes of common bacterial blight pv. fuscans resistance and transfer such resistance into Nebraska elite dry bean lines.Resistant genotypes from the U.S. Dry Bean Core Collection will be crossed with the susceptible cultivar, Orion. F1 will be advanced to F2 through selfing. The F2 will be backcrossed to both parental lines (resistant and susceptible). The six generations from each cross (P1, P2, F1, F2, BCF1P1, and BC1F1P2) will be inoculated with CBB as described above. Parental lines are being increased at the PHREC-greenhouse facilities.DNA from the most extreme segregates (those with very high or very low tolerance) will be pooled to create susceptible and tolerant DNA bulk. RAPD markers polymorphic between the parents and the resistant and susceptible bulk will be screened against the entire F2 population. Significant associations between bacterial CBB and marker genotype will be determined using one-way ANOVA (PROC MIXED; SAS, 1994). Linkage relationships will be determined using MAPMAKER/EXP group command.The CBB pv. fuscans resistance genes, if identified, will be pyramided into current great northern and pinto beans through hybridization.Objective 3: Introgress drought tolerant lines into the Nebraska elite germplasm; and identify QTLs for drought tolerance in dry beans using molecular markers.The shuttle breeding program between Nebraska and Puerto Rico (initiated in 2006) will continue. Two lines, TARS-MST-1 and SB-DT1, with drought/heat and multiple disease resistance, were released by UNL and the USDA-ARS Puerto Rico in 2011. Several lines within different market classes will be released in the next two years.Daily rainfall during the growing season will be recorded. Soil water content will be measured using a Watermark Soil moisture probe on a daily basis. Plant data recorded will include seed yield (kg ha-1), 100-seed weight (g), number of days to flowering and maturity, pod harvest index, leaf temperature, and stomatal conductance. In order to quantify drought severity, the drought intensity index (DII) will be calculated for each environment and averaged across all environments. The drought susceptibility index (DSI) will be used to quantify drought susceptibility of the various lines. The geometric mean (GM) will be calculated to predict the performance of a line under stress and irrigated conditions.