Artificial vernalization in strawberry plants: phyllochron, production and quality

To obtain the best productive performances strawberry plants require an accumulation of cold hours which varies by cultivar; this project evaluated phyllochron, the quality and fruit production from vernalized and non-vernalized seedlings of the strawberry cultivars Albion and Camarosa. The treatments consisted of seedling vernalized before planting for 200 cold hours in a cold chamber with temperatures 4.0 C. Seedlings in the control treatments were not vernalized and were transplanted directly after arrival. Phyllochron was evaluated (estimated by the inverse of the angular coefficient of the linear regression between the number of leaves in the main crown and the sum of thermal time accumulated for each transplanted seedling), in addition to production parameters (number of commercial fruits, number of non-commercial fruits, production of commercial and non-commercial fruits); and fruit quality (titratable acidity, total soluble solids and ratio titratable acidity/total soluble solids). The exposure of strawberry seedlings to vernalization treatments significantly affected productivity but did not affect leaf emission rates or quality of fruits, although these factors were different among cultivars. Camarosa showed greater leaf emission rates and higher productivity per plant and lower titratable acidity than Albion which may be related to genotypic acclimatization. Seedling vernalization is recommended because it results in greater fruit production. The cultivar with higher fruit production is Camarosa.