Identification Of Germplasm Resources Of Pear Cultivars And Screening Of Resistant Resources

The disease resistance of pear is a very important character in the cultivation and production.For a comprehensive understanding about the differences of resistance in Pear Cultivars on main diseases,including pear valsa cancer,black spot and anthracnose.In this study,291 kinds of pear resources belonging to different cultivated species were identified.We established the evaluation system of resistance identification,defined the resistance levels of different breeds and screened out excellent disease resistance resources.The main results are as follows:1.By screening pathogenic bacteria,and optimizing the incubation time for bacteria and branches,we established a screening system of resistant pear varieties about valsa canker.The results showed that F-HN-6 was able to effectively screen the resistant varieties,and found that when the bacteria culture time was 7 days,and brunches culture time was 10 days,the screening effect was best.This experiment used the method of inoculating with isolated brunches to understand the resistance of pear germplasm resources.We evaluated the resistance of 270 pear cultivars about valsa cancer in two years,the results showed great difference between different varieties.Among them,there were 28 resistant varieties,accounting for 10.37%,96 medium resistant varieties,accounting for 35.56%,79 medium susceptible varieties,accounting for 29.26%,67 susceptible varieties,accounting for 24.81%.'Jiuquanchangba','Daxiangshui','Maidiwan','Jinzhoushanli','Zaojinsu','Annonglhao',etc.displayed high resistance,'Huashan','Qiuyue','Lvyun','Hongtaiyang','Zaohuangjin',etc.displayed low resistance;the experiment of different cultivar system showed that Ussurian pear displayed high resistance,Xinjiang pear took second place,and Chinese white pear,Chinese sand pear,Western pear were the worst.2.We initially established the identification in vitro system of pear varieties' resistance about black spot.We used black spot PDA bacteria patties which cultured four days inoculating on the punctured leaves and pericarp,moisturizing and putting them at 28 ?incubator cultured for 4 days,measured lesion to distinguish disease resistance.By using the method of inoculating with isolated leaves and fruits to understand the resistance of pear germplasm resources.We evaluated the resistance of 133 pear cultivars,leaves and 124 pear cultivars' fruits about pear black spot,the results showed great difference between different varieties.Among leaves,there were 12 resistant varieties,accounting for 9.02%,60 medium resistant varieties,accounting for 45.11%,24 medium susceptible varieties,accounting for 18.05%,37 susceptible varieties,accounting for 27.82%.Among fruits,there were 13 resistant varieties,accounting for 10.48%,36 medium resistant varieties,accounting for 29.03%,35 medium susceptible varieties,accounting for 28.23%,40 susceptible varieties,accounting for 32.26%.'Huobali','Dayexue','Xingyeli','Lanzhoushanli','Kushi',etc.displayed high resistance of leaf;'K9','Hangqing','Xinxue','Jinhua','Baxing',etc.displayed high resistance of fruit.The experiment of different cultivar system showed that Xinjiang pear displayed high resistance of leaf;Chinese sand pear displayed high resistance of fruit.3.We initially established the identification in vitro system of pear varieties' resistance about anthracnose.We used anthracnose PDA bacteria patties which cultured four daysinoculating on the punctured leaves and pericarp,moisturizing and putting them at 28? incubator cultured for 4 days,measured lesion to distinguish disease resistance.By using the method of inoculating with isolated leaves and fruits to understand the resistance of pear germplasm resources.We evaluated the resistance of 121 pear cultivars' leaves and 123 pear cultivars' fruits about pear anthracnose,the results showed great difference between different varieties.Among leaves,there were 2 resistant varieties,accounting for 1.65%,35 medium resistant varieties,accounting for 28.93%,40 medium susceptible varieties,accounting for 33.06%,44 susceptible varieties,accounting for 36.36%.Among fruits,there were 1 resistant varieties,accounting for 0.81%,24 medium resistant varieties,accounting for 19.51%,50 medium susceptible varieties,accounting for 40.65%,48 susceptible varieties,accounting for 39.02%.'Jinchuanyeshenglierhao','Huobali','Ganguxiangshui','Hongxiao-1 ','Tiantang',etc.displayed high resistance of leaf;'Hangqing','Guiguan','Jincunqiu','Chonghuadali','Lvyun',etc.displayed high resistance of fruit.The experiment of different cultivar system showed that Xinjiang and rootstock pear displayed high resistance of leaf;Rootstock and Western pear displayed high resistance of fruit.