Biostimulants affect growth, yield and quality of Eustoma grandiflorum L. and Matthiola incana L.

Lisianthus (Eustoma grandiflorum L.), a member of family Gentianaceae, and stock (Matthiola incana L.), a member of family Brassicaceae, are extensively grown as cut flowers globally  and are also getting popularity in Pakistani markets during recent years. A study was aimed to evaluate the efficacy of various biostimulants on improving the growth, yield, and quality of lisianthus and stock at Floriculture Research Area, Institute of Horticultural Sciences, University of Agriculture, Faisalabad, during 2022-2023. The experiment was laid out individually for each species to elucidate the effects of three different products, viz. Isabion (3 mL L‑1), Humic acid (0.4%) and Corteva XYZ (3 mL L-1). Both experiments were laid out in randomized complete block design (RCBD) with three replications of 20 plants each. Biostimulants were applied at 3 mL L-1 of isabion and Corteva XYZ, while 0.4% humic acid, which were sprayed three times at fifteen days interval until runoff on each species starting after fifteen days of transplanting. Results demonstrated significant differences among treatments for both Eustoma grandiflorum L. and Matthiola incana L. Lisianthus utilized least production time (59 days) when sprayed with Corteva XYZ, while in stock isabion application produced earlier flowers (75.6 days) compared to other tested treatments. Isabion application significantly increased plant height (60.3 and 79.6 cm), floret diameter (39.8 and 4.2 mm), stem diameter (4 and 6.1 mm), stem fresh weight (77.6 and 86.1 g)), stem dry weight (16.9 and 15.1 g) and vase life (8.8 and 7.5 days) of lisianthus and stock, respectively. Greatest leaf area (27.7 and 32.9 cm2) was recorded when plants were supplied with Corteva XYZ for lisianthus and stock, respectively. Greatest chlorophyll contents were recorded (75.3 SPAD) in lisianthus, while (81.6 SPAD) in stock, when sprayed with isabion and humic acid, respectively. Isabion consistently yielded best results indicating its potential as an effective biostimulant for promoting growth, yield, and quality attributes, and may be used by the growers to enhance yield and quality of selected specialty cut species.