Articles
IDENTIFICATION OF GRAFT-TRANSMISSIBLE AGENTS FROM ‘TA TAO 5’ PEACH AND THEIR EFFECTS ON ‘CORONET’ PEACH
Article number
550_44
Pages
309 – 314
Language
English
Abstract
‘Ta Tao 5’ peach has been used as an interstem to delay bloom and reduce scion vigour in other peach cultivars.
Cultivars without this interstem, but having been grafted with ‘Ta Tao 5’ chip buds, also exhibited the same observed effects of delayed bloom and reduced growth suggesting that these effects resulted from graft-transmissible agents.
The ‘Ta Tao’ series of germplasm is reportedly infected with Peach Latent Mosaic Viroid (PLMVd), the recently reported Asian Prunus Virus (APV), and Apple Chlorotic Leaf Spot Virus (ACLSV). ‘Ta Tao 5’ is thought to contain only PLMVd and ACLSV. To determine if the observed effects could be linked to the presence of graft-transmissible agents, trials involving trees of the peach cultivar ‘Coronet’ grown in both plastic containers and the field were established.
Half of the trees in each trial were ‘inoculated’ using chip buds from ‘Ta Tao 5’. Dot-blot hybridisation using [32P]-labelled cRNA probes confirmed the transmission of PLMVd from the ‘Ta Tao 5’ buds to the inoculated trees.
The presence of ACLSV in inoculated trees was confirmed using a nested RT-PCR procedure.
Transmission of PLMVd was 100%. Transmission of ACLSV was less than 100% in the inoculated trees, and ACLSV was detected in a few of the non-inoculated trees.
Subsequent tests indicated that the source of ‘Coronet’ contained ACLSV but the infection affected relatively few buds.
Phenological data were collected for 3 years.
Significant differences in the time of bloom, autumn leaf defoliation, vegetative shoot vigour, and fruit ripening date were observed in the treated trees.
All observed effects could be related to the presence of PLMVd, but not ACLSV. Trees in which PLMVd was detected, but in which ACLSV was not detected, did not perform differently from trees in which both PLMVd and ACLSV were detected.
Since delaying bloom to minimize risk from late spring freezes is a desirable practice for peach production in the south-eastern United States, inoculation of existing orchards with PLMVd to manipulate bloom date may be useful in orchard management.
Cultivars without this interstem, but having been grafted with ‘Ta Tao 5’ chip buds, also exhibited the same observed effects of delayed bloom and reduced growth suggesting that these effects resulted from graft-transmissible agents.
The ‘Ta Tao’ series of germplasm is reportedly infected with Peach Latent Mosaic Viroid (PLMVd), the recently reported Asian Prunus Virus (APV), and Apple Chlorotic Leaf Spot Virus (ACLSV). ‘Ta Tao 5’ is thought to contain only PLMVd and ACLSV. To determine if the observed effects could be linked to the presence of graft-transmissible agents, trials involving trees of the peach cultivar ‘Coronet’ grown in both plastic containers and the field were established.
Half of the trees in each trial were ‘inoculated’ using chip buds from ‘Ta Tao 5’. Dot-blot hybridisation using [32P]-labelled cRNA probes confirmed the transmission of PLMVd from the ‘Ta Tao 5’ buds to the inoculated trees.
The presence of ACLSV in inoculated trees was confirmed using a nested RT-PCR procedure.
Transmission of PLMVd was 100%. Transmission of ACLSV was less than 100% in the inoculated trees, and ACLSV was detected in a few of the non-inoculated trees.
Subsequent tests indicated that the source of ‘Coronet’ contained ACLSV but the infection affected relatively few buds.
Phenological data were collected for 3 years.
Significant differences in the time of bloom, autumn leaf defoliation, vegetative shoot vigour, and fruit ripening date were observed in the treated trees.
All observed effects could be related to the presence of PLMVd, but not ACLSV. Trees in which PLMVd was detected, but in which ACLSV was not detected, did not perform differently from trees in which both PLMVd and ACLSV were detected.
Since delaying bloom to minimize risk from late spring freezes is a desirable practice for peach production in the south-eastern United States, inoculation of existing orchards with PLMVd to manipulate bloom date may be useful in orchard management.
Publication
Authors
P.G. Gibson, G.L. Reighard, S.W. Scott, M.T. Zimmerman
Keywords
PLMVd, ACLSV, Dot-blot, nested RT-PCR, bloom, scion
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