Physiological and Biological Quality of Lettuce (Lactuca sativa L.) Cultivars Grown in Different Growing Systems Under Protected Condition
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Date
2018-06
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University of Agricultural Sciences, Dharwad
Abstract
An experiment was conducted at the Hi-Tech Horticultural Unit, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad during kharif, 2017-18 with factorial CRD design. Two factors of experiments were growing systems viz., soil based growing system, aggregate media hydroponics growing system (cocopeat as substrate), nutrient film technique (NFT) and lettuce cultivars viz., Locarno RZ, Concorde RZ, Starfighter RZ.
The morphological parameters viz., plant height (45.8 cm), number of leaves (35.3), leaf fresh weight (96.73 g) and root length (45.84 cm) were significantly highest in nutrient film technique and lowest in soil. Leaf area (2552.0 cm2 plant-1) was significantly highest in nutrient film technique whereas leaf dry matter percentage (4.55 %) was significantly highest in soil grown lettuce at bolting.
Physiological parameter like relative chlorophyll content (29.47 SPAD value) and biophysical parameters viz., photosynthetic rate (18.57 µmol CO2 m-2 s-1), transpiration rate (6.994 mmol H2O m-2 s-1) and stomatal conductance (0.647 mmol CO2 m-2 s-1) of lettuce cultivars were significantly higher in nutrient film technique and least in soil.
Yield parameter like marketable number of leaves, leaf fresh weight of total marketable leaves per plant and number of marketable leaves per square meter was 27.7, 260.66 g and 719 respectively and quality parameters viz., anthocyanin content (146.03 µg 100 g-1 fw) and ascorbic acid content (7.029 mg 100 g-1 fw) was significantly highest in nutrient film technique.
The cultivar Starfighter RZ recorded significantly highest relative chlorophyll content (38.39 SPAD value), photosynthetic rate (18.27 µmol CO2 m-2 s-1), marketable number of leaves harvested per plant (25.2) and also other growth parameters compared to other cultivars. Overall performance of growing systems were in decreasing order of nutrient film technique followed by aggregate media hydroponics followed by soil based growing system. The cultivar Starfighter RZ had best performance among the cultivars.