Resistance to Multiple Tuber Diseases Expressed in Somaclonal Variants of the Potato Cultivar Russet Burbank

Table 1

Severity of tuber soft rot in selected potato cv. Russet Burbank variants. Tubers were tested against Pectobacterium carotovorum subsp. carotovorum (Pcc) and P. atrosepticum (Pa) using two different inoculation techniques (T1 and T2—surface bruise; T3—cut) with an incubation period of 14 days.

Variants	Relative tuber disease severity^a			Disease severity (rotted tissue %)^b
				T1 (surface bruise)		T2 (surface bruise)		T3 (cut)
	Common scab	Powdery scab	Soft rot	Pcc ^c	Pa	Pcc	Pa	Pcc	Pa
A380	0.19	0.44	0.49	7.22^a	9.03^a	9.78	5.37^a	23.71	2.37
A168a	0.21	0.36	0.71	20.44^b	18.15^abc	14.2	22.00^b	—	—
TC-RB8	0.57	0.98	0.76	15.60^ab	23.29^bc	21.80	12.89^ab	16.78	3.17
A362	0.66	0.80	0.73	26.66^bc	12.61^ab	20.62	14.97^ab	—	—
Russet Burbank (parent)	1.00	1.00	1.00	34.21^c	29.63^c	19.02	24.42^b	21.68	3.65
𝑃				<0.001	0.006	0.229	0.007	0.441	0.331
LSD (0.05)			12.09	12.88	ns	10.82	ns	ns

—: lines not tested within the specified trial.
^aMean relative disease severity scores for common scab, powdery scab, and tuber soft rot were generated for each variant by dividing the mean disease score of each variant by the mean disease score of the parent cultivar in each trial in which they appeared and averaging the result. Common scab data are from [3] and powdery scab data are from [2].
^bPercentage of rotten tissues from individual tuber was calculated (𝑛=12).
^cMeans followed by the same letter within the same column are not significantly different at 𝑃=0.05 using Fisher’s LSD test; ns: nonsignificant.