كليدواژه :
بيماريهاي گياهي , PYTHIUM گونه , چغندرقند , پوسيدگي , استان خوزستان , Pythium , Sugar beet rout rot , Khuzestan
چكيده لاتين :
To study the role of Pythium species assosiated with sugar beet root and crown rot during two growing seasons 2002 and 2003, disease samples and soil samples from sugar beet fields were collected from different regions of Khuzestan province including Ahwaz, Andimeshk, Behbahan, Dezfoul, Safi Abad, Shoush Danial, Shoushtar, Kesht va Sanaate Shahid Beheshti and Kesht va Sanaate Shahid Rajayee. Decaying root segments were washed and cultured on CMA supplemented with antibiotics (Pimarcin, Ampicilin, Rifampicin, Benomyl and PCNB). Pythium isolates were recoverd from soil by citrus leaf bailing methode. Species were identified based on morphological characters of sexual and asexual organs, cardinal temperature for growth and colony morphology on various media. From 580 isolates of Pythium recovered, 6 species and two groups were identified as: P. aphanidermatum, P. deliense, P.okanoganense, P. oligandrum, P.salinum , P.tracheiphilum, Pythium G. "F"and Pythium O."G". P.salwum and P. tracheiphihtm are new for Iran flora.Palhoginicity tests were carried under greenhouse conditions using sterlized soil artificially infested with vermiculite inoclum. P. aphanidermatum and Pythium G. "F"respectively caused severe seed rot and seedling dampping off. P. deliense, P. oligmuirum and P.salinum were less pathogenic. Other species are none pathogenic.
