Functional Growth Analysis of Field Grown Strawberry

Abstract

Field grown strawberry plants ( Fragaria × ananassa Duch.) of an advanced breeding selection (OR-US 4681) were harvested every 3–4 days during establishment and through fruiting the next spring. Plant dry weight and leaf area increased rapidly during mid-summer, then slowed and finally ceased in October. Absolute growth rate (AGR) peaked at 1 g dry matter/day near 1 Sept., then fell to zero by early October. Over this period, there was a decrease in weekly mean temperature (37%), solar radiation (47%), and daylength (35%). Maximum values of relative growth rate (RGR) (0.044 g/g/day) and unit leaf rate (ULR) (9 g/m 2 /day) were determined at the start of sampling at the end of June; both rates declined steadily thereafter. The following April through June, both plant dry weight and leaf area increased exponentially, whereas RGR remained constant at 0.02 g/g/day, and ULR rose from 5.5 to 6.5 g/m2/day. The rate of dry matter accumulation in fruit was exponential, whereas it was linear in leaf lamina and stems (crowns plus petioles). A much smaller proportion of dry matter was partitioned to leaves during fruiting than during plant establishment.