Biochemical screening of advanced potato lines for tolerance against rhizoctonia solani

Potato (Solanium tuberosum) is a starch rich tuberous crop of Solanaceae family. Potato is known to be indigenous to Chiloe Archipelago and its cultivation dates back 10,000 years. In the early and mid sixteenth century it was introduced to Europe and the marines introduced it to the territories all over the world. In Pakistan potato was cultivated on an area of 154317 hectares with total production of 2538971 tons in the year 2007-08. During the present study three potato lines viz. VR96, VR94725 and V3 were investigated for reducing sugar, starch and vitamin C after artificial inoculation with Rhizoctonia solani for 40 days and compared with control. The reducing sugar content in control samples ranged from 13.22 to 13.38% while in inoculated samples it ranged from 5.51 to 5.22%. Starch and vitamin C content were significantly affected by inoculation. In control the starch varied from 38.37% in VR96 to 46.56% in V3 whereas in inoculated samples the starch ranged from 24.27 % in V3 to 31.09% in VR94725. Similarly the vitamin C ranged from 3.32 to 4.25mg/100gm in control samples whereas in inoculated samples it ranged from 1.69 to 2.21mg/100gm.