Twenty nine cowpea genotypes, including four Ugandan genotypes, were evaluated for grain yield, protein stability and adaptability under diverse environments in a randomized complete block design with three replications. The analysis showed that cowpea grain yield and protein content were significantly (P < 0.01) affected by genotypes (G), environments (E), and interaction (G x E). Genotypes C2T and C2I had the highest grain yield and protein content respectively, but both were only adapted to specific environments. Genotypes C1J, C1V, C2A, C2O, and C2R were adapted to three environments with high yield which was stable. Similarly, genotypes BRS Pujante, C1J, C2Q and CIT also expressed high protein levels with high stability and wide adaptability. The study further revealed that Namulonge 2014B, Serere 2014A, Serere 2014B and Serere were the most favorable environments for obtaining high yield and protein respectively, because at these four environments, mean yield and protein were higher than the overall mean. All Brazilian genotypes had high protein levels compared to Ugandan genotypes indicating the potential of Brazilian genotypes in improving cowpea seed protein content in Uganda.

Pseudocercospora griseola the casual pathogen for angular leaf spot (ALS) on common bean (Phaseolus vulgaris) is highly variable with many different races occurring in different agro-ecological zones. Therefore, for an effective breeding program, there is a need to continuously monitor the distribution and variability of the pathogen as a means of guiding breeders on which races to target. A study was conducted to assess the incidence, severity and variability of P. griseola in bean growing districts of Dokolo, Lira, Apac, Sironko, Mbale, Rakai, Lwengo, Bukomansibi, Kabale and Kisoro in Uganda. Forty five out of 80 isolates collected were tested on a set of 12 international bean differentials cultivars for ALS. Molecular markers were also used to elucidate the variability among isolates. In all districts, ALS was found wide spread with a mean incidence of 49.9%. Dokolo district had the highest disease incidence and severity, while Kisoro registered the lowest values respectively. In terms of altitude, incidence (60%) and severity (45%) were high for bean fields located between 1000-1200 m and low disease incidence (33.6%) and severity (20.7%) for fields lying above 1500 m. The standard differential cultivars and molecular markers defined 12 pathotypes and 30 haplotypes respectively. These belonged to Middle America and Andean group with considerably high level of diversity. Our findings indicated the presence of ALS in Uganda with high incidence, severity and variability across districts and altitudes. Hence strategic interventions involving integrated disease management and breeding for durable resistance are required to manage the disease.

Angular leaf spot (ALS), a fungal disease caused by Pseudocercospora griseola, has a significant impact on bean productivity in Africa, causing up to 80% yield losses. Efforts to breed for ALS resistance are challenged by continuously evolving pathogen races that differ by location. Released bean varieties in Uganda are susceptible to ALS; the few exotic sources of resistance available are not well adapted to local environmental conditions. To overcome these challenges, a study was conducted to understand pathogen variability and identify new sources of ALS resistance for deployment in ALS resistance breeding. Variability in 45 P. griseola pathotypes was elucidated using a set of 12 ALS differential cultivars, random amplified microsatellite markers, and conserved sequences. The differentials and markers defined 12 pathotypes and 30 haplotypes, respectively, which belonged to the Middle American and Andean gene pool groups, each with high variability. Among the 74 bean landraces screened using the 1:6, 17:39, 21:39, and 61:63 P. griseola pathotypes, only U00279 showed consistent resistance to all the four pathotypes. U00297's resistance to pathotype 17:39 was conferred by a single dominant gene, while digenic epistatic gene interactions were responsible for resistance to other pathotypes. The dominant gene in U00297 was independent of resistance genes harbored by documented resistance sources AND277 and G5686. The results revealed high variability in P. griseola and identified a new source of broad ALS resistance. The divergent inheritance patterns of resistance to the different pathotypes indicate the importance of race specificity of the target host plant in breeding for disease resistance.

Aims: The study was conducted to determine the effectiveness of pyramided genes in improving angular leaf spot (ALS) resistance in susceptible common bean cultivars. Study Design: The experiment was set in randomized block design with three replications. Place and Duration of Study: The experiment was conducted at International Centre for Tropical Agriculture (CIAT) at Kawanda, Uganda in 2010-2014. Methodology: Crosses among three Pseudocercospora griseola resistant lines of common bean (Phaseolus vulgaris) were developed. The crosses involved five inbred lines, AND277, Mexico 54, G5686 and two susceptible cultivars, K132 and Kanyebwa. The resistant lines were crossed in cascading pyramiding scheme to develop triple crosses (TC). The TC F 1 and each of the resistant parents were crossed with each of the two susceptible cultivars to generate four parent crosses Original Research Article

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