Dennis Katuuramu (PhD student, Michigan State University) with a farmer group in Kamuli, Uganda evaluating a dry bean participatory trial.

A subset of the Andean Diversity Panel (ADP) comprised of 23 genotypes was screened on-farm across three districts in Uganda in 2015. The genotypes represent various market classes and were selected for faster cooking times and superior nutritional quality profiles. A participatory variety selection approach was used where the farmers belonging to nine farmer groups participated in the collection of both qualitative data (preference scores) and quantitative data (disease reactions, plant architecture, and seed yield). Farmers also rated seed quality preferences after harvest. In general, farmers preferred high yielding early maturing lines that exhibited tolerance to too little and/or too much water. A small seeded red mottled variety (Chijar) from Puerto Rico was consistently the most productive across all the agro-ecological zones used in the study.

Dr. James Bokosi performing single plant selections from PIC populations in Malawi

Beans are an important crop in Malawi both nutritionally and for income generation, however, production does not meet the demand and with actual yields (400 kg ha^-1) well below potential yield (2,000 kg ha^-1). The major yield constraints range from poor agronomic practices, soil infertility, lack of improved cultivars, and drought. To this end, a program for common bean improvement was initiated for Malawi under the Feed-the-Future Grain Legumes program with Bunda College titled “Advancing dry bean germplasm and cultivar development for resource poor farmers in Malawi.” Bunda College is a campus of the Lilongwe University of Agriculture and Natural Resources (LUANAR) located 30 km from Lilongwe.

The project started in the 2014/2015 crop growing season through testing of Andean Diversity Panel (ADP) lines, Phaseolus Improvement Cooperative (PIC) breeding populations, and National Bean Yield Trials (NBYT). The ADP lines were grown at two sites, Bunda and Bvumbwe. The PIC populations were grown at three sites: Bunda, Bvumbwe, and Bembeke. The National Bean Yield Trial (NBYT) was grown at five sites: Bunda, Bembeke, Bvumbwe, Kasungu, and Champira and were composed of materials from the Bean/Cowpea CRSP project conducted from 2004 to 2007. These materials will be tested for their potential for release as new cultivars in Malawi. The seed types ranged from small- to large-seeded and from solid to mottled seed coat colors. The lines are a mix of Andean and Middle American lines and a variety of seed types including black, small red, carioca, brown, sugar cranberry, large red and red mottled.

The 2014/2015 crop growing season was an unfavorable year for crop growth and production. It was characterized by heavy rains at the beginning leading to floods in some areas, followed by terminal drought to end the season. These conditions affected yields of many crops including beans. Bean yields were below average which made evaluation of materials challenging, however important phenotypic data were collected and selections made.

The performance of 38 ADP lines was evaluated at Bunda College with yields ranging from 139 to 935 kg ha^-1 (ADP-0113=OPS-RS4) and at the Bvumbwe Research Station, where yields ranged from 95 kg ha^-1to 479 kg ha^-1 (ADP-0687=Pink Panther). Calima, a check variety, produced lower yields (289 kg ha^-1) than the grand mean (386 kg ha^-1).

A total of 480 single plant selections were obtained from 35 PIC populations. About 8 to 10 F4 plants were selected from each PIC population, planted in three replications, at the Bunda and Bvumbwe locations. Fewer selections were completed at the Bembeke location due to an unfavorable growing environment resulting from soil infertility, disease pressure and drought. The F5 plant rows from F4 plants were then planted in collaboration with Deidre Fourie at the ARC in South Africa. About 390 F5 progeny lines were selected from the generation advance in South Africa and sent to Malawi for evaluation during the 2016 field season.

The advanced breeding lines in the NBYT were ranked at each site based on yield. Entry F11 MDRB (B) 25 was ranked 1^st at three sites: Bunda, Bvumbwe and Champhira, and ranked 2^nd at Kaluluma; entry F3 MDRB (A) 8 was ranked 2^nd at three sites: Champhira and Bembeke EPA; and entry F10 BC3 D/N 42 was ranked 1^st, 2^nd and 3^rd at Bembeke EPA, Bunda and Bembeke sub-research stations, respectively. The check variety, Bwenzilaana, was ranked 1^st, 2^nd and 3^rd at Kaluluma, Bembeke sub-research station, and Bembeke EPA, respectively.

Plans for the 2015/2016 growing season include continued evaluation of the ADP and continued selection from PIC populations. In addition, a new set of 35 PIC populations will be evaluated that will feed into the National breeding program. National yield trials on advanced lines will also be conducted that include the eight best lines from 2014/2015 combined with a new set of eight lines from preliminary yield trials. Overall this collaborative project is nearing the key objective of releasing germplasm or cultivars for bean production in Malawi.

Common Bean Disease Workshop on Angular Leaf Spot and Root Rots
Protea Hotel Kruger Gate, Skukuza, South Africa, July 20-23, 2015

The USDA-ARS Feed-the-Future Grain Legumes Project, in collaboration with ARC South Africa, hosted a consortium of 65 bean scientists from 14 countries, including: 35 participants from 10 African countries, 9 participants from 3 South American countries, and 21 participants from the U.S. including 4 USDA-ARS scientists that represent the ARS-FtF Grain Legumes Project.  Three ARS Administrators were also in attendance including Dr. Roy Scott, Dr. Eileen Herrera, and Dr. Chavonda Jacobs-Young who presented Certificates of Appreciation to three outstanding partners who had made significant contributions to the ARS-FtF Grain Legumes Project.

SEVEN ARS PARTICIPANTS – left to right Karen Cichy, Eileen Herrera, Phillip Miklas, Chavonda Jacobs-Young, Roy Scott, Talo Pastor Corrales and Timothy Porch.

Other organizations participating in and/or sponsoring the event included CIAT, PABRA (Pan Africa Bean Research Alliance), USAID- Legume Innovation Lab, and the Kirkhouse Trust (African Bean Consortium). Event sponsors included Dry Bean Producers Organization (DPO), Pannar Seed, and Syngenta South Africa.

AWARDEES – receiving Certificates of Appreciation from Dr. Jacobs-Young for contributions to the ARS-FtF, Grain Legumes Project included L-R Dr. Deidre Fourie, Plant Pathologist, ARC, South Africa, Dr. Susan Nchimbi-Msolla, Plant Breeder and Geneticist, Sokoine University of Agriculture, Tanzania, and Dr. Consuelo Estevez de Jensen, Plant Pathologist, University of Puerto Rico.

The workshop addressed two common bean diseases of global significance, angular leaf spot which is the most critical disease problem of beans grown in Africa and South America, and root rots which are endemic worldwide. The first two days of the workshop consisted of presentations by keynote speakers and participants concerning the past, present, and future research needs for combating these major disease problems. During the third day participants were split into four working groups: angular leaf spot pathology, angular leaf spot breeding, root rot pathology, and root rot breeding, with each group responsible for presenting future research needs. The fourth day was used for presentations by experts to update the participants on breeding for resistance to bruchid seed weevils and important bean diseases caused by bacterial (common blight, halo blight), fungal (anthracnose, rust) and viral (bean common mosaic virus, bean common mosaic necrosis virus) pathogens. Significant impacts are expected from the global research strategies and collaborations developed by the consortium of scientists to better understand the pathogens, improve pathogen characterization and host screening protocols and tools, and facilitate resistance gene discovery and deployment into improved common bean cultivars for enhanced control of angular leaf spot and root rot diseases worldwide.

Group of women scientists in attendance at the workshop

In collaboration with Drs. Susan Nchimbi and Paul Kusolwa, Sokoine University, single plant selections were completed from 35 PIC populations and a number of trials were evaluated in Arusha and Mbeya, Tanzania from 6/07 to 6/13/2015.

Single plant selections from 35 PIC populations were completed at Selian (Arusha; left photo) and at Uyole (Mbeya; right photo) Stations.

Evaluation of the ADP

A subset of 47 lines from the ADP population, that performed well in 2014, were evaluated at the Selian Station in Arusha for white mold; and in Mbeya for rust, angular leaf spot and vigor. This ADP subset was replicated three times. The average score for ALS was 5.7, and for rust and vigor were 3.9 and 3.0, respectively, in Mbeya. Tanzanian breeding lines were identified with potential for release.

Evaluation of the Durango Diversity Panel

Two hundred pinto, pink, small/medium red, and great northern lines and cultivars were evaluated in Arusha and Mbeya, for reaction to rust, white mold, angular leaf spot and adaptation. The full range of response was seen for each disease, from very susceptible to resistant, and good production potential was noted for some genotypes at both sites. Much of the germplasm in this panel was well adapted to both environments. Openness to seed types in Tanzania may create an opportunity for pinto and great northern market classes, while the small red class is already an acceptable market class.

 Single Plant Selection from PIC populations

Single plant selections from 35 PIC populations were completed at Selian (Arusha; left photo) and at Uyole (Mbeya; right photo) Stations. About 600 selections were completed. Plant rows of selections from 2014 from the PIC-005 population, Canada (ADP-0010) x CAL 143, and from the PIC-003 population, Kilombero (ADP-0004) x AND 277 population, showed no disease in Arusha and were evaluated for rust and angular leaf spot in Mbeya. These lines show promise for future release.

Through coordination by James Bokosi (Bunda College), 35 PIC populations were grown at three sites in Malawi:

1. Dedza District – (Bembeke Research Station) which is well known for heavy disease pressure and degraded, low fertility soils (low N, P and pH);
2. Bunda College Farm—which was fertilized but was experiencing drought conditions;
3. Bvumbwe—which exhibited the best growing conditions but suffered disease pressure.

The 35 populations were developed from crosses between ADP lines with superior performance across different countries and stress conditions and a list of them is available on the ARS-FtF website http://arsftfbean.uprm.edu/bean/?page_id=2

Plants were selected based on agronomic performance and tolerance to biotic and abiotic stresses in the field without regard to seed types. The F5 seed from each individual F4 plant will be planted as F5 plant rows in the off-season in order to obtain enough seed for thorough evaluation and selection among these fixed breeding lines during the next growing season in Malawi in 2016. It is expected after sorting based on seed shape and color that about 500 F5 lines will be selected.

Local common bean market classes present at a road-side stand in Malawi

Evaluation of the ADP

A subset of the ADP population consisting of 40 lines was evaluated at two locations: Bunda College Farm and at Bvumbwe Research Station. The African landraces Kiangwe, Kasukany, Kokola, and Kablanketi Ndefu stood out and a few lines from N. America performed well: Silver Cloud, VA19, and Pink Panther. Poor plant stand was observed for 30% of the plots and appeared to be due to a field effect not genotype. Good stand establishment for all of the ADP and PIC materials at Bvumbwe site indicated that the seed source from S. Africa had good germination quality. Drought was the prevailing stress at Bunda.

National Bean Trials

The Bunda National Bean Trials consisted of 16 entries which included 15 advanced lines and one common check Kalima (CAL 143). The lines were a mix of Andean and Middle American lines and a variety of seed types including black, small red, carioca, brown, sugar cranberry, large red and red mottled. The trials were planted at three research stations and three on-farm trials: Dedza District, Champhira, and Kukuluma. The Middle American materials outperformed the Andean lines at all sites, but a few Andean lines showed promise.

A simple cart was constructed from the design of White and Conley (2013) (https://www.crops.org/publications/cs/pdfs/53/4/1646) in Mayaguez, Puerto Rico for the Climate-Resilient Bean project. The original cart was designed at the USDA-ARS, U.S. Arid-Land Agricultural Research Center in Maricopa, Arizona. The design was modified to include a steering mechanism for the back tires in order to facilitate turning the cart in the field (photos below). The cart was designed to be able to cover two rows of common bean, while the distance between the tires can be adjusted for different row widths and for transport in the back of a standard pick-up truck.

The cart is being used for the collection of canopy temperature, plant height, leaf area, and GPS location data from field plots related to a Feed the Future Bean Innovation Lab for Climate-Resilient Beans (http://www.feedthefuture.gov/article/feed-future-innovation-labs). This research aims at identifying mechanisms associated with abiotic stress tolerance in common bean.

The design of the field data collection cart includes a bar for turning the wheels of two bicycles to facilitate movement through the field. Computer, GPS, sensors, and datalogger equipment are mounted on the cart for the collection of field data (as per White and Conley, 2013).

White, J. W. and Conley M. M. 2013. A flexible, low-cost cart for proximal sensing. Crop Science 53:1646-1649.

This study examined the nodulation characteristics of 400 lines from the Andean Diversity Panel (ADP). Inoculation with Rhizobium tropici strain CIAT 899 and Rhizobium etli CIAT 632 was carried out in a screenhouse using pasteurized sand in benches. Ten seeds per cultivar/line were sown from each line after surface disinfection with 10% bleach, followed by rinses with sterile water. The Rhizobium strains were grown individually in a Yeast Mannitol Broth Media.  Five days after sowing the seedlings, they were inoculated with 1 ml of 1 x 10⁹ rhizobia cells/ml. Rhizobia counts were conducted with a hematocytometer and the estimation of the viable rhizobia cells was carried out in Yeast Mannitol Agar using the drop plate method. The inoculation consisted of applying 1 ml of the Rhizobium broth culture of each strain separately onto the stem of each seedling. Cultivar Verano was included as a local check with each group of ten lines evaluated in sequential plantings. Nodulation was evaluated 12 days after inoculation by counting the nodules in the upper 3 cm of the roots and the location of the upper-most nodule (UMN) was measured in cm.  In the combined analysis for both Rhizobium strains, the results showed contrasting results in nodule numbers resulting from the inoculation with R. tropici and R. etli with 134 different ADP lines (Figure 1). Lines that formed the greatest number of nodules 12 days after inoculation in the upper 3 cm of the root are shown in contrast with ADP lines that had the lowest number of nodules (Figure 1).

Even though all 134 ADP lines nodulated with both strains, significant differences (P > 0.05) were found between Rhizobium tropici and Rhizobium etli in the number of nodules produced by each strain (Figure 2). The 134 ADP lines produced the highest number of nodules with Rhizobium etli. These findings are particularly important since reports indicate that Andean genotypes prefer R. etli over R. tropici. However, from the 134 ADP lines, ADP-390, 456 and 514 nodulated better with R. tropici than with R. etli. The outstanding lines for overall nodulation were ADP-186, 225, 302, 368, 390, 444, 456, 477 and 514.

Luseko Chilagane working with Ana Vargas at the ARS in Mayaguez, Puerto Rico.

Luseko Chilagane, PhD student in Dr. Susan Nchimbi’s program at Sokoine U. in Morogoro, Tanzania completed a workshop on biological nitrogen fixation at the U. of Puerto Rico in collaboration with Dr. Consuelo Estevez de Jensen and worked on collaborative research on Angular Leaf Spot (ALS) at the ARS in Mayaguez, Puerto Rico. ALS is a widespread disease in Southern and Eastern African common bean production zones, and a critical constraint to common bean production there and in Latin America. Luseko Chilagane and Luz Miryam Serrato, a PhD student at the U. of Puerto Rico researching ALS, worked on PCR amplification and sequencing of specific loci from ALS isolates collected in both Puerto Rico and Tanzania. This diversity analysis will yield important information regarding ALS variability and the corresponding response in common bean.