Seasonal Plant Shading, Growth, and Fruiting in ‘Earliglow’ Strawberry

Abstract

Abstract ‘Earliglow’ strawberry ( Fragaria × ananassa Duch.) plants were covered with 60% shade cloth in Wisconsin and Ohio during each of the following developmental phases: 1) check, no shade; 2) the runnering period after plant establishment; 3) flower initiation period in Fall 1983; 4) early growing season (from mulch-off until first flowering); 5) the fruiting period, 1984; and 6) constant shade. ‘Earliglow’ has a photosynthetic light response curve typical of a C, plant. Leaf dry weight per plant was decreased at both locations by constant shading during the fruiting period, just prior to plant sampling. Crown dry weight was reduced by constant shading. Leaf nutrient element contents of K, Ca, Mg, B, and Fe varied by location, but were not appreciably affected by shading treatments. Shading during the active runnering period resulted in increased total yield the following spring by 12% in Wisconsin and 17% in Ohio. In Wisconsin, increased total yield was the result of increased number of fruit in midseason harvests. Berry size was increased for constant shading or shading during fruiting, but yield was offset by lower fruit numbers. Usable fruit in Ohio on plants shaded during runnering was increased by 20% compared to the unshaded control. Constant shade resulted in an 18% and 46% reduction in total yield in Wisconsin and Ohio, respectively. Shading during the fruiting period resulted in yield reductions in both Ohio (13%) and Wisconsin (27%). Yield reductions were also noted in Ohio when shading occurred during early spring (21%), just prior to fruiting, or during flower formation (24%) the previous fall. Shading during the spring growth and fruiting period delayed fruit maturity and peak harvest 5 to 7 days.