Identification of Powdery Mildew Physiological Race in Seed-used Pumpkin Cucurbita pepo L.）and Genetic Analysis of Its Resistance
LI Shujie1，WANG Ping1*，YANG Yongsheng1，ZHANG Lidong2，LIU Qi2，WANG Jing3，WANG iming4，YE Yingjie2
1College of Horticulture and Plant Protection，Inner Mongolia Agricultural University，Hohhot 010010，Inner Mongolia，China；2Tongliao Academy of Agricultural Sciences，Tongliao 028015，Inner Mongolia，China；3Tongliao Economic Crops orkstation，Tongliao 028000，Inner Mongolia，China；4Agricultural Technology Extension Center of Baotou ，Baotou 14010，Inner Mongolia，China
Abstract：Identification was carried out on powdery mildew pathogenic species of seed-used pumpkin Cucurbita pepo L.）from different regions of Inner Mongolia by morphology and molecular biology ethods．The physiological race of powdery mildew from different regions were identified by using the nternational common used 13 different identification hosts of powdery mildew and identification system．The resistance of 20 seed-used pumpkin germplasms was evaluated，and statistical analysis on 6 generations rogeny resistance was carried out using artificial inoculation method at the seedling stage．Studies on genetic esistance of powdery mildew was also carried out．The results of morphological identification indicated that he powdery mildew of seed-used pumpkin had bunchy ellipsoidal conidium having corpus fibronsum．The esult of molecular identification showed that the rDNA-ITS sequence of powdery mildew was in a branch with he sequence of Podsphaera xanthii，published in GenBank．The powdery mildew in Inner Mongolia region as identified as P. xanthii，and 4 physiological races of powdery mildew identified in Inner Mongolia region ere race 4，race 2F，race 1，and one unknown race．The test results of germplasm resistance showed that mong the 20 seed-used pumpkin germplasms 7 were disease-resistant，4 with medium-resistance，and 1 with igh-resistance．The powdery mildew resistance genes of seed-used pumpkin in Inner Mongolia region were ontrolled by a pair of major recessive single gene．
