Effects of production system and transplanting time on yield, quality and antioxidant content of organic winter squash (Cucurbita moschata Duch.)

Abstract

Research was carried out on butternut squash cultivar “Waltham F1”, following the organic agriculturepractice, in order to evaluate the effects of two production systems (open field and greenhouse) and fourtransplanting times (16 April, 30 April, 14 May, 28 May in the open field; 2 April, 16 April, 30 April, 14May in the greenhouse) on growth, productivity and fruit quality indicators at harvest and during aneight months storage of fruits. Yield, number and mean weight of fruits showed a better performancein greenhouse than in open field crops. The highest yields were recorded with the second and the thirdtransplanting time. Greenhouse crops produced fruits with higher values of dry weight, sucrose, totalproteins and ascorbate, whereas the open field cultivation produced fruits with better values of glucose,fructose, total acidity, ash, colour and carotenoids content. Most quality indicators increased from thefirst to the fourth transplanting; starch, total proteins and ascorbate did not vary. The open field cropsproduced fruits with higher content of calcium, potassium, copper and iron, but lower nitrates comparedwith the greenhouse cultivation. The fruit mineral content decreased from the earliest to the latest trans-planting time, with the only exception of calcium, which increased. During the eight months storage acomplex evolution pattern was recorded: dry matter and starch content in the fruits decreased; glucoseand fructose increased; soluble solids, sucrose, acidity, total proteins, ash and colour showed an initialincrease followed by a later decrease; the mineral composition did not change with time.The greenhouse system proved to be more effective than the open field management in terms of yieldand, to a certain extent, of fruit quality. The intermediate transplanting performed in the second half ofApril in greenhouse, and in the first half of May in the open field, gave the nearest match in yield and fruit quality