EFFECT OF ORGANIC GROWING SUBSTRATES AND SELENIUM ON FRUIT QUALITY AND YIELD OF STRAWBERRY CULTIVARS IN HYDROPONIC CULTURE

Abstract

The choice of appropriate growing substrates is an important factor in promoting the optimum growth of crops like strawberry plants. Mixing coarser materials with growing substrates in different ratios can improve the physicochemical properties of growing substrates. Selenium is another important mineral for human health. The content of selenium in strawberries can be increased by the application of selenium during cultivation. Therefore, an experiment was carried out to evaluate the physicochemical properties of the organic growing substrate mixture and their influence on the growth of the plant and yield of strawberry cultivars with the application of selenium in a hydroponic system. Treatments considered four types of organic growing substrate mixtures (viz., M 1 = 60% rice husk + 30% coconut coir + 10% vermicompost; M 2 = 60% coconut coir + 30% khoa + 10% vermicompost; M 3 = 60% sawdust + 30% khoa + 10% vermicompost; and M 4 = 60% ash + 30% khoa + 10% vermicompost). four levels of selenium (viz., Se 0 =0 mg L -1 selenium, Se 1 =1.0 mg L -1 selenium, Se 2 = 2.0 mg L II -1 selenium, and Se 3

selenium) and three varieties (viz., V 1 : Local Strawberry-1, V 2 : Local Strawberry-2, and V 3 : Local Strawberry-3). The physicochemical properties of growing substrate mixtures and the growth, yield, physiological traits, quality of fruits, and phytochemicals of strawberry cultivars were measured. The highest pH (6.88) was found in M 4 , which was not suitable for strawberry production, while a suitable pH (6.25) was found in M 1 . Bulk density, Water retention, air-filled porosity, and dry weights of substrate mixtures were higher in M 1 and lower in M 3 . The highest plant height (26.16cm), number of fruits per plant (13.08), individual fruit weight (23.85g), fruit length (4.51cm), fruit diameter (4.14cm), fruit volume (22.23 cc), yield per plant (311.96 g), ascorbic acid content (71.29 mg/100 g FW), TSS (16.14°Brix), total phenolic content (150.77 mg/100 g FW), total anthocyanin content (8.25 mg/100 FW), total flavonoid content (5.97 mg/100 FW), and selenium contents in fruits (1.63 mg/100 DW) were found in M 1 = 3.0 mg L , while the lowest in M 3 . The highest number of fruits per plant (11.96), individual fruit weight (24.93g), fruit length (4.89cm), fruit diameter (4.26cm), fruit volume (20.38 cc), yield per plant (298.16g), ascorbic acid content (68.12 mg/100 g FW), TSS (14.25 °Brix), and selenium contents in fruits (3.28 mg/100g DW) were found in Se 3 while the lowest were in Se 0 . The highest total phenolic content (139.37 mg/100 g FW), total anthocyanin content (7.44 mg/100 g FW), and total flavonoid content (5.0 mg/100 g FW) were found in Se 2. The highest plant height (23.65cm), number of fruits per plant (14.13), individual fruit weight (25.70g), fruit length (4.61cm), fruit diameter (4.11cm), fruit volume (20.52 cc), yield per plant (363.14g), ascorbic acid content (70.41 mg/100 g FW), TSS (16.15°Brix), total phenolic content (150.14 mg/100 g FW), total anthocyanin content (8.63 mg/100 FW), total flavonoid content (5.86 mg/100 FW), and selenium contents in fruits (1.59 mg/100 DW) were found in V 1 while the lowest in V 3 . Therefore, the Se 2 formulation can be used for fruit quality, and the Se 3 formulation can be used for the growth and yield of strawberry cv. Local strawberry-1 along with M 1 growing formulation in a solid hydroponic system in Bangladesh.