بررسی امکان ایجاد پایه های مقاوم سیب زمینی به بیماری خال سیاه از طریق ریز ازدیادی

Black dot of potato , a disease caused by the fungus Colletotrichum coccodes,can result in significant yield losses in the field and loss of quality of infected tubers in storage.We applied Potato dextrose agar (PDA) medium that generally have been using for routine isolation and growing of Colletotrichum coccodes on roots,stem bases and tubers. MS liquid medium used for propagation of fungus extract .Colonies of fungus in M.S.liquid medium was spherical white. Bodies of fungus had been blender and then was extracted by a exteractor filters of 10 millipore . Agria and Marfona cultivars were used for propagation of meristem culture and sprout propagation. Shoots that was achieving from meristem culture and sprots had divided in segment with 5-7 mm in height, they were ready for transplanting into flasks containing a suitable high organic mixture and various dosage mixture of fungus exteract with Morashige skook and nitch &nitch medium. Flasks of Plantlets and nodal cuttings was transfered into greenhous with 18-25 c and 14 h photoperiod.with whit cold flurescent. Every dishes was a plot containing cultivar in two level(Agria ,Marfona) ,concentration of fungus extract in three level( low,medium,high), MS and nitch &nitch culture medium with factorial design.After four weeks plantlets that reached 4 to 5 Cm were transferred to pot in green house . pot medium culture was mixture of perlite and peat moss .After 70 to 80 days minitubers were harvested. Datas of analyses variance detected that cultivar and cultivar ا fungus extract effect had different significant on producing of plantlets at 5% level with Duncan s Multiple Range test.Means comparating had shown that control and low concentration of fungus extract did not different significant on producing of plantlets (average product was 2.7 plantlets number in two treatments).means number of plantlets production had different significant at 1% level in control treatment with two concentration of fungus extract (medium and high concentration). In producing of minitubers only explants that aquered with low concentration of fungus produce minitubers compared with two other concentration. in totally Marfona produce more minituber than Agria in control and low concentration treatments.