Identification Of Pepper Varieties Resistant To Phytophthora Capsici And Screening Of Antagonistic Bacteria Against Phytophthora Capsici

Pepper is an important horticultural vegetable with a high economic value,but it has been threatened by pepper blight for many years.In this experiment,the effects of differe-nt medium and light conditions on the growth and development of Phytophthora capsici were investigated.The antagonistic bacteria were isolated from the rhizosphere soil of the pepper protection ground,and 23 pepper samples were inoculated with Phytophthora cap sici to screen resistant varieties,achieved the following research results:?1?The mixed vegetable juice medium?V8?and carrot solid medium?CA?can pro-mote the reproductive growth of Phytophthora capsici,and is more suitable for cultivat-ing Phytophthora capsici colonies that need to obtain a large number of zoospores.Soy solid medium?BA?can Promote the growth and development of Phytophthora capsici co-lony,which is more suitable for the Phytophthora capsici colony which needs to obtain a large number of mycelium;the light will obviously inhibit the vegetative growth of Phyt-ophthora capsici,but the short-term illumination can promote the formation of Phytoph-thora capsici spores and the releasion of zoospores.?2?By separating the fungal bacteria in the root soil of the protected pepper,and get a strain of Aspergillus niger J-01 which is antagonistic to Phytophthora capsici,can inhi-bit the growth and infection process of Phytophthora capsici by the plate confrontation test.The pot experiment proved that the antagonistic bacteria can effectively reduce the incidence of high blight resistant varieties and delay the onset time of low blight resistant varieties.?3?The apparent characteristics of different varieties after inoculation with Phytoph-thora capsici were observed and the disease index was calculated.In general,the materi-als of Japanese chaotian pepper and erjintiao pepper had the strongest disease resistance,followed by materials dongxing pepper,Chuannong Pepper No.1 and Dongxing Horn-sh-aped pepper,which also showed Strong ability to infect Phytophthora infestans.The Kor-ean long pepper,bian pepper No.1,and L_{2-7-2-9-7-1-1-1} showed lower disease resistance.?4?The catalase,peroxidase,superoxide dismutase,polyphenol oxidase,phenylalan-ine ammonia lyase,?-1,3 glucanase,chitin of pepper plants before and after infection were determined.Activity and values of the enzyme and cell membrane permeability catalase activity decreased signifycantly after infection,and superoxide dismutase,poly-phenol oxidase,phenylalanine ammonia lyase,?-1,3 glucanase,chitin of pepper plants showed differrent degrees of increase.Cluster analysis showed that materials Dongxing Horn-shaped pepper,erjintiao pepper,and Japanese chaotian pepper had the strongest resistance to pepper blight,followed by materials Chuannong Pepper No.1 and dongxing pepper.And The disease resistance of chaotianpepper L_2-1-1,L_{10-9-1-1-1-4-1-1-1},bullet pepper,haijiao pepper,hang pepper No.1,8819 Line pepper was at a medium level in the materia-ls of this test.,materials jinyu green pepper,grainless pepper,chaotianhuang pepper,yuh-ang pepper No.4,Multi-grain pepper,and chaotian pepper are at a lower level,materials Korean long pepper,bian pepper No.1,L_{2-7-2-9-7-1-1-1},lixian long pepper and lixian Horn-shaped pepper are at a low level of disease resistance,and weiyuanxindianqixing pepper have the lowest disease resistance.?5?Among the 23 test materials,the materials with higher resistance to pepper bligh-t were screened out.Japanese Chaotian pepper and erjintiao pepper were the most compr-ehensive resistant varieties,while Dongxing Horn-shaped pepper,Chuannong PepperNo.1,Dongxing Pepper Can also be used as an excellent disease resistant breeding mate-rial.