Plant age, time of digging and carbohydrate content in relation to storage mortality and post storage vigor of strawberry plants
Hicklenton, P.R. and Reekie, J.
ISHS Acta Horticulturae 513: 237-246.
1998
บทคัดย่อ
In northern regions strawberry nursery plants are often dug in the late Fall, stored over winter at - 1.5 to -2.0°C and shipped to growers in the early Spring. Selecting an appropriate digging date is essential to the successful operation of this system since plants which are dug too early in the Fall can deteriorate in storage and show poor post-storage vigor. Plants of Kent, Veestar and Bounty were harvested at 10 weekly intervals beginning on October 3, in 2 consecutive years from 3 fields in the Annapolis Valley, N.S. In the first year (1995) first daughter plants were stored over winter at -1.5°C and then assessed for mortality and post-storage vigor when planted to the field. In the Fall of 1996 first, second and third daughter plants were harvested to assess the combined effects of plant age/size and time-of digging on post-storage vigor. Field measurements of crown temperature were used to calculate accumulated chilling hours (<8°C) for each year. Plant mortality at different digging dates varied with year and daughter position - third daughter plants showed reduced survival at early dates - but all plants dug after November 7 showed full survival. Plant vigor (number of daughters and runners) increased in all cultivars and plant ages at the later digging dates but in most cases there was little benefit in delaying digging beyond November 20. Early dug plants had relatively low concentrations of leaf and root glucose, fructose, sucrose and raffinose, high leaf starch and low root starch concentrations. Concentrations of leaf sugars (particularly glucose and fructose) were higher in 1996 (a year with below average temperatures) than in the previous year (with above average temperatures), but root starch was lower. The results suggest that optimum digging dates vary little from year to year and are not closely related to seasonal temperature conditions.