ارزیابی مقاومت نسبی ارقام و لاینهای سویا به بیماری بوته میری فیتوفترایی

‭Phytophthora root and crown rot of soybean can be found everywhere around the country especially in Lorestan province and has been one of the most important factor in decreasing of the soybean planting areas. The objectives of this research was two fold. I-Exert a fast,accurate and simple method in inoculation of soybean seedlings and 2-Evaluation of som~ soybean lines and cultivars to an aggressive isolate of P.SOjCl. During the years 1379-80 some plant disease samples in different stages were collected and after disint~cti()n.sm~\l1 tissues from stem and crown and root were put on the semi-selective media.PARPH.Finally S isolates of Phylophlhora were achieved.B~sed on morphological and some physiological characters,all isolates were identified as Phyiophilloia .wj" .Pathogenicity of the isolates was tested on Williams cultivars seedling by hypocutyl inoculation method. Williams seedlings were sowned in 10-cm pots containing. l1!ixture or sand and soil( 10 seedlings in each pot at least) and then maintained in 2S"c greenhouse condition.1noculation was provided on LBA plates that were cultured with 2-3 chunks of P. .'i(~i(l :.md maintained in 2SoC during a period of 10-14 days.The isolate.PS3.had the ~re"test puthogenicity on Williams (100% damping-orO. So it was used in resistance lcsts.!n these tests,seeds were sowned in a pasteurized mix of soil and sand in 10-cm seedlings per cultivar( 10-14 day old plants) were inoculated using the wound~d hypocutyl technique.This method involves cutting an agar culture (2x 3mm~).m