Genetic Diversity Analysis of the Main Commercial Varieties of Brassica napus in Guizhou Province

[Objective] The aim was to investigate the genetic diversity of the main commercial varieties of Brassica napus in Guizhou Province at the molecular level. [Method] Nine main commercial rapeseed cultivars in Guizhou were detected by 40 pairs of SSR primers used in the national regional trial of B. napus, and then clus-tering analysis was carried out. [Result] A total of 191 bands were amplified, and 143 （accounting for 75%） of them showed polymorphism among the nine rapeseed cultivars. By cluster analysis, the nine cultivars were divided into two groups. Group A included seven varieties, and group B consisted of two cultivars from Guizhou In-stitute of Oil Crops. The cultivars in group A were further divided into sub-groups A1 and A2 at the similarity coefficient of 0.643 4. Sub-group A1 included three culti-vars from Guizhou Rapeseed Institute, and sub-group A2 included the other four cultivars from Guizhou Institute of Oil Crops. [Conclusion] The cultivars bred by the same institute had similar genetic background. The cultivars from Guizhou Institute of Oil Crops showed wider genetic basis. However, the genetic similarity coefficient between Qianyou 17 and Qianyou 29 was up to 0.87, suggesting that they shared closer genetic basis.

Variation for Resistance to Alternaria tenuissima and Potential Structural Mechanism among Different Cultivars of Chrysanthemum morifolium

Black spot disease,caused by the necrotrophic fungus Alternaria tenuissima(Fr.)Wiltsh(A.tenuissima),is considered a highly destructive disease of Chrysanthemum(Chrysanthemum morifolium Ramat.).A set of 17 accessions of commercial chrysanthemum cultivars were evaluated for resistance to A.tenuissima by seedling artificial inoculation.It was found that the reaction of the accessions to artificial inoculation ranged from resistant to highly susceptible.Five varieties of chrysanthemum(‘Zhongshan Taogui’,‘Jinba’,‘Zhongshan Jinguan’,‘Jinling Wanhuang’and‘Jinling Yangguang’)were resistant;two varieties of chrysanthemum(‘Zhongshan Xinggui’and‘Zhongshan Jinkui’)were moderately resistant;and others were susceptible to various degrees,four varieties of chrysanthemum(‘Zhongshan Zihe’,‘Zhongshan Jiuhong’,‘Zaoyihong’and‘Jinling Jiaohuang’)were highly susceptible,especially.Some leaf morphological features of two resistant and two highly susceptible cultivars were further researched.Trichome density,length,height,gland size and stomata density were found to be associated with plant passive resistance.Resistant varieties that were identified in present study will be promising germplasm for exploitation of breeding programmes aimed at developing A.tenuissima-resistant cultivars and increasing genetic diversity.

COMPARISON OF POMELO(CITRUS MAXIMA)GROWN IN CHINA AND THAILAND

Pomelo is a member of the genus Citrus that is a key contributor to the breeding of modern citrus cultivars.China is the largest producer of pomelo and one of the top five pomelo exporting countries.Pomelos from Thailand are also well-known for their excellent quality and flavor and are ranked in the top ten export countries.This review introduces pomelo planting locations and conditions in China and Thailand.The characteristics and qualities of some commercial pomelo cultivars in China and Thailand are summarized to introduce them to international consumers and to document their similarities and dissimilarities.Data on bioactive compounds and antioxidant capacity are also included for most Chinese and Thai pomelos to highlight how they differ in this aspect because consumers are increasingly interested in healthier foods.In addition,the sensory perception in terms of aroma,flavor,texture and taste attributes,consumer perspective and preferences are discussed.