Application of indole-3-butyric acid by fertigation on pepper plants in soilless culture grown in a greenhouse

Hormones play an important role in the physiological processes, which take place in a plant, and low levels of hormones may be required for normal plant growth. Exogenously applied plant growth regulators may affect the growth and development of plant, but little is know about how they act when they are added to the nutrient solution. Two years of field experiments were conducted in a greenhouse located in El Ejido area of Almeria, Spain during 2001-2002 and 2002-2003 growing seasons, to evaluate the effects of two concentrations (0.5 and 1.0 L ha^-1) of a commercial indole-3-butyric acid (IBA 0.4 %, Exuberone®) applied weekly into nutrient solution from early fruit development in grown pepper plants in soilless culture. The substrate used was perlite in bags of 40 L. The design was randomized complete-block. Fruit number, weight and yield; fruit firmness, total soluble solids and fruit dry matter; the root weight, volume and root dry matter; also the water use efficiency, as well as the nutrients absorption and emission were analyzed. In general, the effects were smaller at the untreated control than from pepper plants treated with growth regulator. IBA 0.4 % at 0.5 L ha^-1 affected marketable production and root parameters. IBA 0.4 %-induced pepper harvest yield was greater at 0.5 L ha^-1 than 1.0 L ha^-1. IBA 0.4 % applied by fertigation promote yield increase by increasing root parameters, enhancing nutrient uptake. These results demonstrated that applying IBA 0.4 % at 0.5 L ha^-1 concentration to the root zone by fertigation increase total marketable yield of greenhouse-grown pepper, and reduce ion emission.