Strawberry shape: phenotypic variation in length and width

Fruit of the cultivated strawberry varies widely in shape ranging from oblate to long-conic. Typical short-conic strawberries have length/width of about 0.9-1.1 and long-conic berries 1.2-1.4. We have developed long narrow genotypes with L/W >3.0 and have maintained this form during selection through several generations of crossing. To understand the phenotypic variation in this trait, we crossed K09-11 (L/W=3.4) with the long-conic K09-3 (L/W=1.3) and the broader-than-long 'Flavorfest' (L/W=0.7) and measured the mass, length, width, and equator position (widest point) of the offspring on primary and secondary fruit. The seedlings approximated a normal frequency distribution between the parents for L/W with means closer to the broader parent. Seedling plants with long narrow fruit similar to K09-11 were present but rare. Principal components analysis (PCA) using correlations between measurements identified the importance of fruit width (PCA Score 1) and the length between the fruit equator and tip (PCA Score 2) in describing relationships among measurements. Measurements on secondary fruit gave little additional information to that of the primaries.