Strawberry Growth and Development in an Annual Plasticulture System

The growth and development of three strawberry cultivars commonly grown in a plasticulture system were documented. Strawberry plants were harvested monthly and divided by roots, crown, leaves, flowers, and fruit and then dried in an oven. The dry matter production and resource allocation proceeded along a predictable pattern of development. The establishment phase was characterized by an active period of growth of root, crown and leaves in the fall. Through the winter, the plants underwent slow growth, ending in a transition period in the late winter/early spring when resources were allocated to both vegetative and reproductive growth. In the spring, all plant parts received significantly increased allocation of, or redistribution of, resources. Cultivars of California origin, ‘Chandler’ and ‘Camarosa’, displayed similar trends in yield, dry matter production, seasonal resource allocation, and growth analysis variables throughout the season. ‘Sweet Charlie’, a cultivar from Florida, showed lower dry matter accumulation and relative growth rate in the spring, higher harvest index and lower yield than the California cultivars. physiological performance of the whole strawberry plant over a growing season. Our specific objectives were to: 1) document changes in dry matter accumulation and allocation; 2) chronicle phases of plant phenology; and 3) conduct extensive growth analysis of the three cultivars most commonly grown in North Carolina. Materials and Methods Field experiments were conducted during the 1997–98 growing season. The experimental site was located at the Tidewater Research Station, Plymouth, N.C. (USDA Hardiness Zone 7b, latitude: –76.65, longitude: 35.87). The soil was a Megget fine sandy loam. ‘Camarosa’, ‘Chandler’, and ‘Sweet Charlie’ plants with leaves attached were obtained bare-root from an Ontario, Canada, nursery. A randomized complete block design was used with four replications. Plants were set in 0.76-m wide fumigated beds, with 1.52 m between the centers of each bed. Plants were set on 17 Oct. 1997. Plots were single beds 7.6 m, with double rows of plants staggered 0.3 m apart. Each plot contained 50 plants, with the center 30 plants being designated for fresh fruit harvest. The remaining 20 plants were allotted to whole plant harvest. Standard cultural programs were followed according to North Carolina recommended practices (Poling and Monks, 1994). Whole plants were harvested every 4–6 weeks. At each whole-plant harvest date, four plants of each cultivar were harvested, including all belowground plant parts. Roots were washed over a fine mesh sieve to separate soil from roots. Plants were then divided by roots, crowns, leaves (including petioles), flowers, and fruit. At each whole plant harvest, the number of crowns per plant was recorded. Leaf area of fresh leaves was determined with a LI-COR LI-3200 leaf area meter (LI-COR, Lincoln, Neb.). All plant parts were bagged separately, and placed in a drying oven (Fisher Scientific, Pittsburgh) at 70 °C for 10 d. Growth analysis of relative growth rate (RGR), specific leaf area (SLA), leaf area ratio (LAR), and harvest index (HI) were calculated from recorded total yield, leaf areas, and dry weights of sacrificed plant parts. These indices of plant growth were defined by the following equations: RGR = dW/dt (1/W) [d]