TABLE 3.

Reversion from a range of viruses for sweetpotato cultivars tested using Ipomoea setosa and PCR/RT-PCR in the screenhouse at MUARIK, Uganda

		No. of plants (out of 18) inoculated	Duration of the experiment (weeks) no. of positives out of a maximum of 10 plants
			0	2	4	6	8	10
Virus tested	Cultivar
SPLCUV	New Kawogo	18	10	6	4	3	3	2
	NASPOT 1	12	10	9	3	3	2	0
	NASPOT 11a	6	6	3	0	0	0	0
	Resisto	15	10	6	4	0	0	0
	Beauregard	12	10	10	6	3	3	0
SPFMV (East African strain)	New Kawogo	12	10	9	5	0	0	0
	NASPOT 1	18	10	10	6	0	0	0
	NASPOT 11a	0	0	0	0	0	0	0
	Resisto	18	10	10	10	10	9	8
	Beauregard	18	10	9	9	6	6	4
SPCSV (East African strain)	New Kawogo	10	10	9	10	10	8	9
	NASPOT 1	18	10	10	10	10	10	10
	NASPOT 11a	3	3	3	1	3	3	2
	Resisto	18	10	10	10	10	10	10
	Beauregard	18	10	10	10	10	10	10
SPMMVb	New Kawogo	16	10	8	4	0	0	0
	NASPOT 1	18	10	8	6	2	0	0
	NASPOT 11a	2	2	0	0	0	0	0
	Resisto	18	10	9	6	1	0	0
	Beauregard	18	10	10	8	3	0	0

Note: The I. setosa was side-grafted onto the experimental shoots and remained alive for the whole period of the experiment. The starting point for the experiment (0 weeks) was 1–2 weeks after graft inoculation, as this was the first time at which the virus could be detected. For each virus, a maximum of 10 successfully inoculated plants were chosen and followed for reversion. Shoot tips were sampled every 2 weeks for 10 weeks to test for virus infection (and reversion) by grafting to I. setosa and further testing with PCR/RT-PCR.

Abbreviations: SPCSV, Sweet potato chlorotic stunt virus; SPFMV, Sweet potato feathery mottle virus; SPLCUV, Sweet potato leaf curl Uganda virus; SPMMV, Sweet potato mild mottle virus.

^aFor each virus, this number of NASPOT 11 plants could be graft-inoculated.

^bDetection of SPMMV was performed using I. setosa.