A review of angular leaf spot resistance in common bean.

Angular leaf spot (ALS), caused by Pseudocer-cospora griseola, is one of the most devastating diseases of common bean (Phaseolus vulgarisL.) in tropical and subtropical production areas. Breeding for ALS resistance is difficult due to the extensive virulence diversity of P. griseolaand the recurrent appearance of new virulent races. Five major loci, Phg-1 to Phg-5, confer-ring ALS resistance have been named, and markers tightly linked to these loci have been reported. Quantitative trait loci (QTLs) have also been described, but the validation of some QTLs is still pending. The Phg-1, Phg-4, and Phg-5loci are from common bean cultivars of the Andean gene pool, whereas Phg-2 and Phg-3are from beans of the Mesoamerican gene pool. The reference genome of common bean and high-throughput sequencing technologies are enabling the development of molecular markers closely linked to the Phg loci, more accurate mapping of the resistance loci, and the compar-ison of their genomic positions. The objective of this report is to provide a comprehensive review of ALS resistance in common bean. Further-more, we are reporting three case studies of ALS resistance breeding in Latin America and Africa. This review will serve as a reference for future resistance mapping studies and as a guide for the selection of resistance loci in breeding programs aiming to develop common bean cultivars with durable ALS resistance

Additional file 1: of Genetic characteristics of soybean resistance to HG type 0 and HG type 1.2.3.5.7 of the cyst nematode analyzed by genome-wide association mapping

Sources and distributions of 440 soybean accessions. (PDF 433 kb

High temperature tolerance in grain legumes

High temperature stress (or heat stress) during reproductive stages is becoming a serious constraint to productivity of grain legumes as their cultivation is expanding to warmer environments and temperature variability is increasing due to climate change. Heat stress adversely affects pollen viability, fertilization, pod set and seed development leading to abscission of flowers and pods and substantial losses in grain yield. Photosynthate remobilization has been identified to play an important role in heat tolerance. A high temperature of 35°C was found critical in differentiating heat tolerant and heat sensitive genotypes in chickpea, lentil and faba bean, while heat sensitive lines of common bean lose yield when night temperature is higher than 20°C. Field and laboratory screening techniques have been standardized for screening of genotypes for heat tolerance and sources of heat tolerance have been identified in most of the grain legumes. A heat tolerant chickpea line ICCV 92944 has been released in three countries (India, Myanmar and Kenya) and area under its cultivation is expanding rapidly. Several heat tolerant varieties of faba bean have been released in Sudan giving up to 2-fold increase in yield as compared to the sensitive cultivars. Interspecific crosses have been successfully used for enhancing heat tolerance in beans. Studies on physiological mechanisms and genetics of heat tolerance and identification of molecular markers and candidate genes for heat tolerance are in progress and would help in developing more efficient breeding strategies for heat tolerance in grain legumes