Variability among the potato sclerotial isolates of Rhizoctonia solani of Mountainous Region, Gilgit-Baltistan, Pakistan

摘要

An experiment was carried out to find the variability among twenty sclerotial isolates of Rhizoctonia solani collected from potato growing areas of Gilgit-Baltistan. These isolates were grown in different culture media, mycelial compatibility and fungus protein profile were investigated. Culture media were used to study radial colony growth and sclerotial production of isolates. Radial colony growth (RCG) and sclerotial production (SP) of isolates against culture media ranged from 12.31-21.55; 3.66-22.66 in potato dextrose agar, 12.67-18.56; 4.66-10.66 in czpedox agar, 12.02-20.42; 2.00-8.66 in corn meal agar and 10.54-14.16; 0.00-3.00 in water agar, respectively. These isolates were further classified into three categories on the basis of RCG and SP. Result revealed that out of total isolates, 60% showed medium RCG and 40% fast growth, while 10, 60 and 30% isolates showed low, medium and high SP. Furthermore, sclerotial characteristic such as size, shape and distribution pattern were also recorded. Mycelial compatibility and incompatibility among the R. solani isolates was also studied. The results indicated that out of 190 combinations, 72.10% were compatible, whereas 27.90% were incompatible. Fungus protein profile of twenty isolates of R. solani by sodium dodecyl suplphate gel electrophoresis (SDS-PAGE) recovered sixty one bands with different frequencies among the isolates. Cluster analysis of twenty isolates divided them into two major lineage groups, A and B. Lineage A contained 65% isolates whereas lineage B contained 35% isolates. These lineages were further divided into thirteen clusters (C1-C13); A was comprised of eight and B five clusters, respectively.