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Brassica campestris vegetables play an important role in the Chinese diet. The objective of this study was to evaluate the composition and content of glucosinolates (GSs) in five species of Chinese Brassica campestris vegetables by high-performance liquid chromatography. The compositions and contents of GSs varied significantly among and within species and cultivars. The contents of total GSs were 100 to 130 mg/100 g fresh weight (FW) in turnip (B. rapifera), 50 to 70 mg/100 g FW in purple cai-tai (B. chinensis var. purpurea), and 14 to 35 mg/100 g FW in Chinese cabbage (B. pekinensis), choysum (B. chinensis var. utilis), and pakchoi (B. chinensis var. communis). In Chinese cabbage, the predominant individual GSs were glucobrassicin for both cultivars, neoglucobrassicin only for ‘zaoshuwuhao’, and gluconapin only for ‘zaoshuwuhao’. The predominant individual GSs were glucobrassicanapin and gluconapin in purple cai-tai and choysum and gluconapin in pakchoi and turnip. The relative content of total aliphatic GSs was 80% to 90% in purple cai-tai and choysum, 60% to 65% in pakchoi and turnip, and 17% to 50% in Chinese cabbage. The relative content of total indolic GSs was 37% to 75% in Chinese cabbage, 25% to 27% in pakchoi, and 5% to 17% in purple caitai, choysum, and turnip. The relative content of aromatic GSs was 28% to 36% in turnip, 8% to 14% in Chinese cabbage and pakchoi, and 2% to 4% in choysum and purple cai-tai. These results suggest that there are significant genotypic variations in composition and content of glucosinolates in Chinese Brassica campestris vegetables.
Rust disease, incited by the fungus Uromyces vignae, adversely affects production and quality of asparagus bean and other types of cowpea in many parts of the world. Genetic resistance to the rust pathogen has been identified in a few accessions, but it is difficult to efficiently transfer the resistance to a broad range of asparagus bean cultivars using traditional breeding approaches. We determined that rust resistance was controlled by a single dominant gene designated Rr1 in the cross of a highly resistant cultivar ZN016 and highly susceptible cultivar Zhijiang 282. Bulked segregant analysis was applied to an F2 population derived from these parents, and an AFLP marker (E-AAG/M-CTG), 150 bp in size, was detected in the resistant bulk. The AFLP fragment was then converted to a SCAR marker, named ABRSAAG/CTG98, and the genetic distance between the marker and the Rr1 gene was estimated to be 5.4 cM. This SCAR marker could be used effectively for MAS of Rr1 in breeding programs to develop rust-resistant asparagus bean cultivars and potentially more widely to breed rust-resistant cultivars of other types of cowpea.