THE EFFECTS OF RUNNER GRADE, HARVEST DATE AND PEAT GROWING MEDIA ON STRAWBERRY TRAY PLANT FRUIT PRODUCTION

Strawberry plugs are quickly replacing traditional bare-root transplants in Ireland. This is particularly the case for soilless culture in glasshouse and polythene tunnel production. The aim of this experiment was to study the effect of runner size, date of runner harvest and two peat types on subsequent fruit yield characteristics from the 'tray plants' grown. Runner tips were harvested from 'super elite' strawberry mother plants cv. 'Elsanta' and planted into peat modules and grown in a non-heated glasshouse. Runner tips were harvested on the 5 th and the 19 of July 2005. On both dates they were graded into small, medium and large sizes. These were rooted in one type of propagation tray and two different types of peat substrate. The final strawberry crown diameter ranged from 14.3 to 15.69 mm at harvest. The root score ranged from 3.55 to 4.36 out of a total score of five. There was no significant difference between the total yields recorded in either season one or two for any of the treatments. The lowest and highest average yield recorded over the two seasons was 11.33 and 12.73 kg per m 2 respectively. The average fruit weight was higher from plants propagated from large runners and when grown in the finer peat substrate. However, when large runners were used later in the season, the average fruit weight is lower. Strawberry crown dissection showed the regular pattern of flower formation throughout the growing season. The stage of flower development was closer for the three runner grades that were harvested later.