Viabilitas isolate Pseudomonas solanacearum asal kacang tanah pada varietas kelinci.

Ten isolates of P. solanacearum representing 7 peanut isolates (race 1) and 3 potato isolates (race 3) were tested for their variability in virulences peanut cv. Kelinci, a susceptible cultivar to bacterial wilt. The peanut plants were prepared in plastic pots containing sterilized Cikeumeuh soil. Two week-old plants were inoculated with bacterial inoculum by placing a micropipette tip containing 100 ul inoculum of each bacterial isolates on the third youngest fully developed leaves. The inoculum was prepared by suspending a 48 hour-old culture on an SPA slant in 10 ml sterile distilled water. From initial concentrations of the inoculum, 8.10 at the power of 8 colony farming units (CFU)/ml, a ten-fold serial dilutions were made to 10 at the power of -1; 10 at the power of -2; 10 at the power of -3; 10 at the power of -4; 10 at the power of -5 were made. Ten plants were inoculated with each inoculum dilution. Check plants were inoculated with sterile distilled water. Design of the experiment was a completely randomized block design. Observations were made daily to record disease developments. Wilt intensities were calculated at 14 and 21 days after inoculations. The results indicated the presence of variation in virulence among P. solanacearum isolates collected from different localities on cv. Kelinci. The degree of variability in virulence of the isolates collected by the difference in the incubation period to initiate 50 percent plant wilting and the wilt intensity in the peanut plants inoculated with the different dilution of bacterial inoculum. Isolate Ps 9019 from Ngale (East Java) was the most virulent and aggressive among the seven peanut isolates. Ranking of the isolates from the most virulent to the least virulent one was the Ngale Isolates, followed by isolates Ps 8954 from Malang Ps 9006 from Cikeumeuh (Bogor) and Ps 9027 from Muara (Bogor) which have the same degree of virulence, Ps 9028 from Cikeumeuh, Ps 8974 from Muara and Ps 9060 from Manokwari (Irian Jaya). The three isolates of race 3 were not pathogenic on peanut.