همبستگی بین شیوع و شدت بیماری پوسیدگی فوزاریومی بلال (Fusarium verticillioides) و عملکرد و اجزای عملکرد در ژنوتیپ‌های جدید و خارجی ذرت دانه‌ای در شرایط آلودگی مصنوعی در منطقه‌ی گرگان

Fusarium ear rot is one of the most important maize disease in tropical and subtropical areas of the world, including Gorgan area in Golestan Province. Planting the maize that is resistant to disease is one of the most appropriate methods of control and management of the disease in prevelence areas which causes the less damage to biology. The aim of this research was to study the type and rate of the corellation between incidence and severity of Fusarium ear rot disease (Fusarium verticillioides) and yield and yield componenets in new and forigen genotypes of maize in artificial infestation conditions in Gorgan region. This research was done in the agricultural year 1394-95, in Gorgan agricultural and natural resource research and education center (Araqi area) by using 24 genotype of maize in the format of complete randomized blocks design in four replication. Process of field preparation, planting and cultivation was done according to the common area custom. About 7-10 days after maize crown appearance in field, maize inoculation is done by nail punch method using conidium suspension of pathogenic fungus in volume two mililiter and 106 mililiter density of conidium. About two months later, when inoculation is done at the same time with corns physiologic cultivation level, 10 inoculated maizes of each genotype and practice was collected and evaluated. Disease incidence (DI) percentage based on ratio of infected maize among inoculated maizes, disease severity (DS) percentage based on rate of mycelial coverage of pathogenic fungus on each ear, is measured according to nine numbering scale, Aghajani, et al. (1387). Furthermore, after harvesting, economic yield (ear function by 14% moisture) and yield components (ear length, number of grain row in ear, number of grains in each row of ear, ear diameter, ear stem diameter, garin depth, weight of 1000 granis, biologic yield and harvest index) were measured. Pierson correlation coefficient (r) between DI and DS and yield and yield components were calculated. The results of analysis of data variance and correlation coefficient determination show that there was direct (positive) and meaningful correlation between DI and DS, economic yield and weight of 1000 grains for each 24 tested genotype at statistical probability level (p0.01). The correlation coefficient between DI and economic function and weight of 1000 grains was respectively (r = 0.61) and (r = 0.76). Therefore, the effect of DS on economic function and weight of 1000 grains is more than DS. Then, preventing ear infestation to Fusarium ear rot pathogenic fungus in 24 new and forigen maize genotype in Gorgan area causes significant increase of economic yield and weight of 1000 granis.