Pea (Pisum sativum L.) is an annual cool-season legume crop. Owing to its role in sustainable agriculture as both a rotation and a cash crop, its global market is expanding and increased production is urgently needed. For both technical and regulatory reasons, neither conventional nor transgenic breeding techniques can keep pace with the demand for increased production. In answer to this challenge, CRISPR/Cas9 genome editing technology has been gaining traction in plant biology and crop breeding in recent years. However, there are currently no reports of the successful application of the CRISPR/Cas9 genome editing technology in pea. We developed a transient transformation system of hairy roots, mediated by Agrobacterium rhizogenes strain K599, to validate the efficiency of a CRISPR/Cas9 system. Further optimization resulted in an efficient vector, PsU6.3-tRNA-PsPDS3-en35S-PsCas9. We used this optimized CRISPR/Cas9 system to edit the pea phytoene desaturase (PsPDS) gene, causing albinism, by Agrobacterium-mediated genetic transformation. This is the first report of successful generation of gene-edited pea plants by this route.

Lentil (Lens culinaris Medikus subsp. culinaris, 2n = 14) is a cool-season legume with high production potential for multiple uses. However, limited molecular research has been conducted in this species owing to its large genome, which impedes the generation of genome sequences and the development of molecular markers. In this study, more than 1.37 billion filtered clean reads were collected by RNA-Seq of six diverse lentil accessions and 217,836 transcripts and 161,095 unigenes were de novo assembled, yielding respectively 257.1 and 240.6 million nucleotides. The mean transcript length was 1180 bp and the N50 and N90 lengths were respectively 2075 and 479 bp. The mean length of the unigenes was 1494 bp and their N50 and N90 values were respectively 2203 and 714 bp. The unigenes were annotated against seven databases. The FLOWERING LOCUS T (FT) gene homolog in lentil showed high protein sequence similarity to the FT gene homologs of pea and alfalfa. On the basis of the RNA-Seq analysis, 26,449 EST-SSR markers were designed in silico, and 276 preliminarily screened markers were selected to evaluate polymorphism in 94 diverse lentil accessions. In total, 125 (45.29%) of 276 EST-SSR markers were found to be polymorphic. A total of 130,073 SNP loci were detected and 78 (61.41%) of 127 SNPs were successfully converted to KASP markers. Population genetic analyses of the lentil accessions with EST-SSR and KASP markers revealed similar genetic structures, suggesting that the RNA-Seq-generated resources and the developed markers are reliable for use in molecular marker-assisted breeding of lentil.

As a cool-season crop, pea (Pisum sativum L.) can tolerate frost at the vegetative stage but experiences yield loss when freezing stress occurs at the reproductive stage. Cold-tolerance improvement of pea varieties is important for stable yield and expansion of the winter pea planting area. Under natural low-temperature conditions during winter in Qingdao, Shandong, China, we evaluated the cold tolerance of 3672 pea germplasm accessions in the field and categorized them as displaying high resistance (214), moderate resistance (835), or susceptibility (2623). The highly and moderately resistant genotypes were validated in the following year. We found that genotypes from the winter production region showed higher cold tolerance than genotypes from the spring production region. The accessions identified as having high levels of cold tolerance are recommended as potential genetic resources in cold-tolerance breeding of pea.

Food legumes comprise all legumes grown for human food in China as either dry grains or vegetables, except for soybean and groundnut. China has a vast territory with complex ecological conditions. Rotation, intercropping, and mixed cropping involving pulses are normal cropping systems in China. Whether indigenous or introduced crops, pulses have played an important role in Chinese cropping systems and made an important contribution to food resources for humans since ancient times. The six major food legume species (pea, faba bean, common bean, mung bean, adzuki bean, and cowpea) are the most well-known pulses in China, as well as those with more local distributions; runner bean, lima bean, chickpea, lentil, grass pea, lupine, rice bean, black gram, hyacinth bean, pigeon pea, velvet bean, winged bean, guar bean, sword bean, and jack bean. China has remained the world's leading producer of peas, faba beans, mung beans, and adzuki beans in recent decades, as documented by FAO statistics and China Agriculture Statistical Reports. The demand for food legumes as a healthy food will markedly increase with the improvement of living standards in China. Since China officially joined the World Trade Organization (WTO) in 2001, imports of pea from Canada and Australia have rapidly increased, resulting in reduced prices for dry pea and other food legumes. With reduced profits for food legume crops, their sowing area and total production has decreased within China. At the same time, the rising consumer demand for vegetable food legumes as a healthy food has led to attractive market prices and sharp production increases in China. Vegetable food legumes have reduced growing duration and enable flexibility in cropping systems. In the future, production of dry food legumes will range from stable to slowly decreasing, while production of vegetable food legumes will continue to increase.

Simple sequence repeat (SSR) markers have previously been applied to linkage mapping of the pea (Pisum sativum L.) genome. However, the transferability of existing loci to the molecularly distinct Chinese winter pea gene pool was limited. A novel set of pea SSR markers was accordingly developed. Together with existing SSR sequences, the genome of the G0003973 (winter hardy)×G0005527 (cold sensitive) cross was mapped using 190 F₂ individuals. In total, 157 SSR markers were placed in 11 linkage groups with an average interval of 9.7cM and total coverage of 1518cM. The novel markers and genetic linkage map will be useful for marker-assisted pea breeding.