Dry Bean Improvement for the Northern Plains
April 15, 2003
Plant Sciences Department
North Dakota State University
The objective of the dry bean breeding program at North Dakota State University is to develop high yielding, high quality bean genotypes adapted to the northern Great Plains. As in past years, several hundred unique hybridizations were made in the greenhouse. Parental germplasm consists of adapted cultivars grown in the Northern Plains, breeding lines developed at NDSU, and germplasm possessing desirable traits from other breeding programs. Unadapted germplasm lines from other sources are evaluated for desirable traits and introgressed into adapted material (e.g., pre-breeding). Each year, the breeding program evaluates material from around the world as possible sources of resistance to white mold, rust, root rot, virus, anthracnose, and bacterial blights. To date, the breeding project has made approximately 330 hybridizations, with 150 crosses made for pinto improvement. Hybidizations for navy, black, and kidney bean improvement are scheduled for March, 2003.
Yield Tests, Breeding Nurseries, and Variety Trials
The breeding program had yield tests and/or breeding nurseries at 11 locations in North Dakota and Minnesota [Erie, Hatton (2), Forest River, Johnstown, Fargo, Carrington, Perham, and Park Rapids] in 2002. The white mold nursery was moved from Hatton to Carrington to take advantage of micro-irrigation, allowing both the plant and the pathogen a better opportunity to interact. The white mold trial used rigid set of irrigation pipes fitted with xeri-mister nozzles. These nozzles provide a fine mist (virtually a cloud), keeping the canopy moist and making the environment ideal for disease development. Disease development was excellent, resulting in good separation of materials, and again allowing for several lines, including line AN-37, to continue to show strong white mold resistance.
Two sites near Hatton, one for the variety trial and the other for the breeding nursery were conducted. Heavy rainfall in July resulted in poor growth for yield trials at the breeding site, but segregating populations were not as severely affected. In 2002, pinto (P), navy (N), and miscellaneous (M) bean class variety trials were grown near Erie (P, N, & M), Hatton (P, N, & M), and Forest River (P & N); preliminary and advanced yield tests were grown at Erie, Hatton, Johnstown, and Perham, and Park Rapids. The breeding program tested 42 pinto, 34 navy, 12 black, and 20 kidney bean lines in advanced yield trials. We also tested 168 pinto, 152 navy, 112 black, 40 great northern, and 26 small reds in preliminary yield tests. Preliminary tests of kidney and black were not conducted because due to a shortage of seed. Approximately 1,500 plots were harvested for the variety trials alone; an additional 3,000 test plots of preliminary and advanced yield trials also were harvested. More than 5000 single plant selections were made and harvested from breeding nurseries grown in 2002.
In 2002, breeding nurseries were located at Erie, Fargo, Hatton, Johnstown, Perham, and Park Rapids. Germplasm evaluation nurseries (exotic material) were at Erie, Fargo, Perham, Hatton, and a rust nursery also was at Fargo. Breeding nurseries, yield trials, and other trials totaled more than 10,000 plots planted on about 40-45 acres.
The 2002 growing season was, in general, ranged from poor to very good. While some areas received surplus moisture, these areas were considerably reduced from rainfall extremes experienced in previous years. The weather pattern and reduced disease pressure again resulted in high yields in ND. Even though the region looked as if white mold pressure would be great early in the season, limited rainfall and warm temperatures in late July and early August resulted in minimal damage. Rainfall was critical at the Erie site, which developed into a very good nursery, in spite of receiving limited rainfall in late July and August, during pod fill. This lack of rainfall also hastened maturity of late-season material and brought about reduced seed sizes. Yields also were affected, although the yield trials had very good yield averages. The yield tests at Hatton and Johnstown were lost due to excessive rainfall in June and July. The early generation populations grown at Hatton were less affected by the rainfall (better runoff). The breeding nursery site at Perham, however, had moderately severe root rot pressure, which allowed us to differentiate those that had some levels of root rot resistance compared to the susceptible check Montcalm. The test site near Park Rapids was under center pivot irrigation and produced good yields, although, overall, plants exhibited a lack of late season N, which affected yields.
Approximately 5,000 single plant selections were made, considerably less than in 2001. However, because of the heavy rainfall that occurred at the Hatton site, many populations were advanced using the single pod descent method (one pod harvested from each desirable plant in the population - seed is then bulked to plant a population the following year). After harvest, these single plant selections were evaluated again for seed type in the seed lab, and the lines with the best pinto and navy seed traits will be entered into preliminary yield trials or plant rows (dependent on amount of seed) Lines from the 2002-03 winter nursery will form the basis of the segregating populations for 2003. Approximately 90% of the breeding effort is placed on pinto bean and navy bean improvement. Lines from single plant selection of pink, great northern, small red, black, and kidney will be evaluated in 2003 in ND and Minnesota.
Breeding lines were evaluated in the greenhouse during the winter for the presence of BCMV resistance genes I, bc22, and bc3. Lines are discarded if resistance genes are not present. Incorporating adequate levels of BCMV resistance into pinto bean breeding lines improves the overall desirability of experimental lines because of the threat of virus infection in western seed producing states. Lines also were evaluated for rust resistance, using a composite of isolates collected from North Dakota. High levels of resistance were identified in lines from a number of market classes.
In cooperation with Plant Pathology Department, two anthracnose isolates (races 7 and 73), obtained from Michigan State University, are being used to screen for resistance to this disease. These two races represent the two most common anthracnose races in the U.S. We are continuing our evaluation of material, including parental material and advanced bean lines. Now that this disease has been found in North Dakota, it is imperative that we place greater resources on incorporating resistance to this pathogen in adapted lines.
Canning trials of pinto bean and navy bean breeding lines are conducted for all advanced and some preliminary trials, depending on seed supply. In these canning trials, experimental lines are rated on overall appearance, on a subjective scale of 1 = superior to 7 = poor appearance (4 = average), relative to released commercial cultivars (prior to 1995, a 1 to 5 scale was used). These cultivars also serve as yield and agronomic checks in the yield trials. The objective of these canning tests is to identify both potentially superior genotypes, which would be advanced for further evaluation, as well as inferior genotypes, which would be eliminated from the breeding program. Current samples are being canned and evaluated by USDA-ARS personnel in Michigan at no cost to our program, other than seed shipment.
Breeding Other Market Classes for the Northarvest Region
The objective of this program is to allow the dry bean growers of the Northern Plains to diversify into other market classes, thereby increasing the possibility of further exports. As indicated, breeding programs for dark and light red kidney, pink, small red, black, and great northern bean market classes also are underway. Pink, small red, and great northern market classes are closely related to pinto bean, while black is similar to navy bean; materials used to improve the two major market classes may also be used to improve these other, minor classes. Determining that cranberry bean production was minimal the past several years allowed us to focus those resources in pinto bean improvement. Plant rows were evaluated in 2002 and preliminary yield trials of black beans, pinks, great northern, and reds also were grown.
White Mold -- White mold (Sclerotinia sclerotiorum) continues to be a serious problem for dry bean growers and is ranked as the disease of most concern by producers. The potential for improved genetic resistance as a control measure has been demonstrated. Two major mechanisms of genetic resistance to white mold exist: 1) avoidance - usually associated with improved plant architecture; and 2) physiological - associated with biochemical functions at the cellular level. Generally, greenhouse and laboratory methods screen solely for physiological resistance, whereas field plantings screen for both physiological and avoidance mechanisms. Thus, greenhouse and laboratory resistance may not correlate well to field resistance. The breeding project has relied on evaluating material in the field at Hatton, where a 12 entry National White Mold Nursery also was grown. This national nursery is grown in Michigan, New York, Nebraska, Colorado, and Ontario, Canada. We have since moved the white mold location to Carrington, where we can take advantage of a better management scheme for use of a solid set irrigation system.
An NDSU navy bean breeding line, 88-106-04, continues to provide good levels of resistance and is used in the NDSU program as a source of resistance. We are transferring this resistance into pinto bean, which is our greatest challenge. We are collaborating with USDA-ARS in this area in order to obtain an additional white mold site. This population was tested in two environments in 2001 (Prosser, WA at a site with center pivot irrigation) and near Hatton, ND (natural rainfall, natural infection, well protected) and again at Prosser and Carrington in 2002. Lines differed dramatically for reaction to white mold, with several lines showing minimal white mold infection at both sites. One line, AN-37, had the best overall score for white mold tolerance. This line, which is early with a small pinto seed type, was incorporated into the 2002 pinto crossing block. Several NDSU navy bean breeding lines have shown excellent white mold resistance in both field and greenhouse trials, but this may be due, primarily to escape. We are continuing to develop populations using Othello and lines from the USDA Plant Introduction Collection that contain some level of white mold resistance, in cooperation with Dr. Jack Rasmussen, Plant Pathology, NDSU.
Rust -- Rust (caused by Uromyces appendiculatus) has, at times, been a severe disease problem, particularly for pinto bean producers. This fungal pathogen is composed of many races (at least 46 in the United States and over 200 worldwide) and has the capability to increase in variability, since it can complete its entire life cycle on the bean plant. Resistance usually is controlled in a single gene fashion, whereby one gene in the plant imparts resistance to one specific race of the pathogen. Often, this type of vertical resistance is short-lived, because the selection pressure placed on the rust race forces a change in the rust population. As a result, a new rust race is developed, and the former resistant variety becomes susceptible. This was observed in the pinto variety Olathe which, when first grown in North Dakota, was completely resistant, but was susceptible to at least one component of the rust population.
A rust nursery grown annually at Fargo is used to identify field response to the rust population that exists in North Dakota. The nursery is artificially inoculated with a collection of rust made the previous year. A collaborative nursery to determine potential adaptation of material into which exotic genes for resistance have been incorporated was planted. In 2002, we evaluated more than 200 lines (pinto, great northern and red) for reaction and overall adaptation. These lines were developed cooperatively between NDSU and USDA-ARS for high levels of resistance to rust and other bean diseases. From this effort, we have jointly released with USDA more than 30 lines possessing virtual immunity to rust.
Root Rot -- A root rot nursery was established at Perham to identify resistant genotypes and incorporate the resistance into adapted, high quality, high yielding kidney and cranberry beans. I have identified many lines with less disease damage, and some lines that essentially have no disease development on the roots. We need to continue to evaluate material in the field because of the nature of the complex. Efficient evaluation of material can occur in the greenhouse, but evaluation for reaction to only one pathogen at a time can be made. In Minnesota, there may be as many as five genera that may be causing damage: Fusarium (2), Pythium, Rhizoctonia, or Aphanomyces, so field screening is critical.
Because of the excellent performance of VAX 3 and VAX 5, two common bacterial blight lines developed at CIAT, the International Center for Tropical Agriculture, Cali, Colombia, in the root rot trial at Perham in 2000, we are using these lines as sources of resistance to both CBB and root rot. We have developed populations with these lines as sources of resistance, which are being advanced rapidly in the greenhouse for further evaluation. VAX 3, which possesses a red seed coat, also has high levels of resistance to anthracnose, bacterial blights, and rust and is being used as a source of resistance for other market classes as well as kidney bean.
Bean common mosaic virus -- We continued to screen for BCMV resistance in order to assure production of quality seed. This virus, which is occasionally observed in ND, is prevalent in the Pacific North West region, which affects seed production and, ultimately, supply. Selection for two resistance genes allows us to assure that the virus will not be problematic in NDSU material. Since the virus is seldom seen in ND, we evaluate material for reaction to this disease only during the winter months in the greenhouse. We have transferred resistance genes into Maverick by backcrossing, increased the seed in Idaho in 2002, and will begin yield testing these lines in 2003.
Anthracnose -- In 1998-99, we began identifying material that was used in the breeding program which possessed resistance to this disease. Several races of this disease are found worldwide, but the two most prevalent in the U.S. are races 7 and 73. Race 7 primarily attacks kidney bean and cranberry beans, but usually does little damage to cultivars of pinto, navy, black, and other market classes. Race 73, on the other hand, does primary damage to pinto, navy, black, and others, but usually has no effect on kidney and cranberry. Now that the disease has been found in ND, we have given breeding for resistance to this pathogen our greatest disease priority. Focusing our efforts on this problem will allow us to make good progress in incorporating resistance genes into adapted material. We are primarily interested in using the Co-42 gene for resistance, simply because we can screen for the presence of this gene in the absence of the pathogen by using molecular markers. This will allow us to rapidly backcross this resistance gene into desirable genotypes. Other sources of resistance also will be exploited, because our greatest chance of controlling this pathogen is to combine several resistance genes into our cultivars.