Changes in Morphological, Biochemical and Physiological Traits in Strawberry in the Northeastern United States During One Hundred Years of Breeding

摘要

Two of the more popular northeastern strawberry cultivars from each decade spanning 1891 - 2003 were obtained from various sources and grown in a common environment. Morphological, physiological and biochemical traits were measured in each cultivar to determine if directional changes have occurred through selective breeding over time. Fruit firmness, size, and fruit set increased over time, whereas soluble solids and leaf area ratio (LAR) decreased. Photosynthesis tended to become less efficient over time, while plant pigments showed no consistent change. Yields peaked in the 1980s and have remained somewhat constant for the past 30 years. For most traits, cultivars exhibited values midway between those of the progenitor species, suggesting that traits are partially heritable. F. chiloensis appears to have a more efficient photosynthetic apparatus than F. virginiana, so might be a good candidate for recurrent breeding. We suggest several approaches for productivity improvement including increasing fruit number per plant, modifying plant architecture and carbon allocation, improving carbon assimilation and increasing photosynthetic efficiency. Incorporating day neutrality into adapted cultivars also could have a significant impact on yield.