Effects of Plant Covers and Mulching on the Biometric Parameters, Yield and Nutritional Value of Tomatillos (Physalis ixocarpa Brot. Ex Hornem.)

The aim of this study, which involved a field experiment conducted in north-eastern Poland, is to evaluate the phytometric parameters, yield, and biological value of fruit of three tomatillo cultivars grown in soil mulched with black PE (polyethylene) film and covered with PE film and non-woven PP (polypropylene) fabric. A two-factor field experiment was conducted in 2015 and 2017-2018 in the Agricultural Experiment Station owned by the University of Warmia and Mazury in Olsztyn. In the control treatment, tomatillo plants were grown without protective covers or mulch. Tomatillo fruits were harvested gradually, upon physiological maturity, which was determined based on changes in the color of the peel and calyx, and the aroma. The growth and development of tomatillos were evaluated based on plant measurements performed in the field. The chemical composition of tomatillo fruits was analyzed at the stage of full fruiting. During the three-year study, the weight, vertical diameter, and horizonal diameter of fruit were highest in cv. 'Rio Grande Verde' and lowest in cv. 'Purple'. The combined use of mulch and plant covers accelerated fruit ripening. The total and marketable yields of tomatillo fruit were highest in cv. 'Rio Grande Verde' and lowest in cv. 'Purple'. The fruit of cv. 'Purple' had the highest content of dry matter, total sugars, extract, beta-carotene, and total polyphenols.