Impact of Monosporascus cannonballus on growth parameters of melon plants

In hot and arid areas، root rot and vine decline of melon plants caused by Monosporascus cannonballus is considered as one of important diseases in Iran. The pathogen infects melon plants at early growth stages and causes root rot followed by a decrease in root and vine weight in susceptible melons. However، the effect of the pathogen on plant growth parameters needs further research. In this study، one of pathogenic isolate of M. cannonballus was inoculated to 10 different genotypes of muskmelon and cantaloupe locally named: Samsoori، Jalal، Sooski، Shahabadi، Ahmadi، Minoo، Zard-e-Mahali، Mashhadi، Garmsar and Rish baba. The inoculated plants were kept at 27 ± 2 °C for 4 and 32 days before they were examined for the existence of the pathogen using species specific primers. In addition، root and vine fresh weights of inoculated plants were measured after 45 days. Although the pathogen was detected in all samples using molecular markers، a significant difference was observed in the weight of root and vine of the genotypes. Root weight reduction maxima were recorded for Sooski، Samsoori، Garmsar and Zard-e-Mahali as 72. 05، 67. 28، 62. 46 and 54. 60% respectively and the minima were recorded for Minoo and Mashhdi as 22. 25 and 27. 10% respectively. The vine reduction weight of Shahabadi، Zard-e-Mahalli، Ahmadi and Sooski were 61. 92، 58. 64، 53. 75 and 52. 27 and those of Minoo and Mashhadi were measured as 15. 96 and 21. 20%. Based on the fresh weight of root، shoot and total plant، Mashhadi and Minoo genotypes were more resistant compared with Shah Abadi and Suski genotypes.