Identification And Comprehensive Evaluation Of Resistance To PVY Disease In Different Tobacco Varieties(Lines)

In this paper,46 tobacco varieties ere used as test materials to carry out artificially induced PVY test.46 PVY resistance grades of tobacco varieties were identified,and based on disease index(D)and resistance index(RI),clustering method was used to divide the population.The resistance of different tobacco varieties and the classification of their disease resistance.In order to reduce the one-sidedness of the single-indicator analysis,two representative high-resistance varieties(SY04-3.CF222)and four mid-resistance varieties(Piaohe1?Yun87?Longjiang981?Yanshai6),5 medium-sensitive varieties(Yanshai7?Yanshai5?Zhongyan90?Damaxi?Jianpingdarentou)and 1 susceptible variety(NC95)were used as test materials and were inoculated with PVY.The values of antioxidant enzyme activity,dry matter accumulation,photosynthetic efficiency,and chlorophyll content at 14,21,28,and 35 days were used as indexes,and the degree of resistance of 12 tobacco varieties was comprehensively analyzed using the membership function method.The main findings are as follows:1.The results of PVY resistance test showed that 6 test materials for the PVY high resistance variety;SZ08-1?SZ08-3?Jiyan9?Yanshai9?Yanshai6?Yanshai10?Baichenghuboxiang?Yanshai8?Balin sun-cured?Bankun sun-cured?SY03-1?SY04-5?Yanshail?Yun87?Piaohel?8107?Longjiang981,17 test materials for the PVY medium resistant varieties;SZ08-2?Yanshai4?SZ12-01?SZ12-02?SZ12-04?Yanjiqiancengta?SZ12-07?SZ12-05?Yanshai3?Zilaihong?Yanshai2?Yanshai 5?SZ12-06?SZ12-03?B7?Damaxi?Yanshai7?Xiaomaxi?Zhongyan90?Jianpingdarentou and 20 trials of anti-PVY varieties;NC89?K326 and NC95 three test materials were resistant to PVY.2.The clustering analysis results sho,w that regardless of clustering based on the disease index or resistance index,the tested varieties are divided into two categories,the first major group includes two subgroups(I-1,I-2)A total of 23 varieties are included.Among them,I-1 includes:SY04-3?SY04-6?SZ08-04?TN90?CV91?CF222?and six mid-resistant varieties.I-2 includes 17 medium resistant varieties such as SZ08-1?SZ08-3?Jiyan9?Yanshai9?Yanshai6?Yanshai10?Baichenghubouxiang,and Yanshai8;The two large groups also included two subgroups(?-1,?-2),which contained a total of 23 varieties.?-1 includes 20 medium-intensity varieties such as SZ08-2?Yanshai4?SZ12-01?SZ12-02?SZ12-04?Yanjiqiancengta?SZ12-07 and SZ12-05.?-2 includes:NC89?K326 and NC95,3 susceptible varieties.3.The results of physiological and biochemical changes of different tobacco varieties after inoculation showed that the antioxidant enzyme activity of 12 tobacco varieties inoculated after 14 days and 21 days after inoculation was higher than that of the control,showing a trend of increase,and the increase of high resistance varieties was the largest.Followed by mid-resistance varieties and moderately susceptible varieties,and finally susceptible varieties.At 28 days after inoculation,the high-resistance and middle-resistance cultivars still showed a trend of increase,but the inoculation treatment of the middle sensible and susceptible cultivars was lower than that of the control,showing a downward trend.The highest increase was in high-resistance varieties,followed by medium-resistance varieties;the most significant decline was in susceptible varieties,followed by medium-intensity varieties.After 35 days of inoculation,the inoculation treatment was lower than the control treatment,and the trend of decline appeared.The most significant decline was in susceptible varieties,followed by moderately susceptible varieties and moderately resistant varieties,with the lowest drop being high-resistance varieties.The performance of malondialdehyde(MDA)content was opposite to that of antioxidant enzyme activity.Twelve tobacco varieties were inoculated with higher treatment than the control,showing a trend of increase.The most significant increase was in susceptible varieties,followed by moderately susceptible varieties,moderately resistant varieties,and finally high-resistance varieties.In terms of actual photosynthetic efficiency,chlorophyll content and dry matter accumulation,the control treatments of the 12 tobacco varieties were all higher than the inoculation treatment,showing a trend of decline.The descendants ranged from large to small:susceptible varieties,moderately susceptible varieties,medium-resistance varieties,and high-resistance varieties.4.Comprehensive ranking of membership functions:The comprehensive ranking of 12 tobacco varieties resistant to PVY was ranked sequentially from strong to weak:SY04-3>CF222>Piaohel>Yun87>Longjiang981>Yanshai6>Yanshai7>Yanshai5>Zhongyan90>Damaxi>Jianpingdarentou>NC95.Among them,the high-resistance varieties were ranked high,and the membership function values were between 0.7629-0.8309;followed by the mid-resistance varieties,the subordinate function values range is between 0.5228-0.6131;the last was middle-sensing varieties and susceptible varieties.The function value range is between 0.1429-0.4019.SY04-3 had the highest membership function value among the 12 tobacco varieties being 0.8309,with the strongest resistance the NC95 membership function had the lowest value of 0.1429,and the resistance was the weakest.