Articles
INFLUENCE OF HEAT THERAPY ON ROOTING OF, AND ELIMINATION OF RASPBERRY BUSHY DWARF VIRUS FROM, SHOOT CUTTINGS OF RED RASPBERRY
Article number
66_8
Pages
63 – 70
Language
Abstract
Virus-free plants were developed from a raspberry clone infected with raspberry bushy dwarf virus by combining heat therapy with propagation of small shoot cuttings.
Infected plants were decapitated to promote axillary growth, then subject to 16-hour days under three temperature regimes for 28 weeks.
The night-day temperatures were 33–36, 37–39 and 39–42 C. Shoot tips and nodal segments were excised at intervals during treatments, dusted with a rooting hormone and planted in damp sand.
The shoot tips were 0.5–2.0 mm long with the largest leaf at least 10 mm long; the nodal segments were 1–3 mm long with one leaf and a dormant axillary bud.
Treatment temperature had the greatest influence on propagation of cuttings.
Between the two higher temperatures, differences were small, but both were superior to 33–36 C. The higher temperatures stimulated profuse axillary growth, providing more material suitable for cuttings, and these cuttings rooted more readily than those from the lowest temperature.
Nodal segments often rooted more slowly than the shoot tips but eventually 78% of the nodal segments, and 80% of the shoot tips, became established plants.
Length of treatment had the greatest influence on virus elimination.
After 4 weeks treatment, all rooted cuttings were infected; after 8 weeks, 66% were freed at 39–42C, 47% at 37–39 C, and 27% at 33–35 C. After 20 weeks treatment, the virus was eradicated from most plantlets irrespective of the temperature.
Infected plants were decapitated to promote axillary growth, then subject to 16-hour days under three temperature regimes for 28 weeks.
The night-day temperatures were 33–36, 37–39 and 39–42 C. Shoot tips and nodal segments were excised at intervals during treatments, dusted with a rooting hormone and planted in damp sand.
The shoot tips were 0.5–2.0 mm long with the largest leaf at least 10 mm long; the nodal segments were 1–3 mm long with one leaf and a dormant axillary bud.
Treatment temperature had the greatest influence on propagation of cuttings.
Between the two higher temperatures, differences were small, but both were superior to 33–36 C. The higher temperatures stimulated profuse axillary growth, providing more material suitable for cuttings, and these cuttings rooted more readily than those from the lowest temperature.
Nodal segments often rooted more slowly than the shoot tips but eventually 78% of the nodal segments, and 80% of the shoot tips, became established plants.
Length of treatment had the greatest influence on virus elimination.
After 4 weeks treatment, all rooted cuttings were infected; after 8 weeks, 66% were freed at 39–42C, 47% at 37–39 C, and 27% at 33–35 C. After 20 weeks treatment, the virus was eradicated from most plantlets irrespective of the temperature.
Authors
F. C. Mellor, R. Stace-Smith
Keywords
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