Response of different growing media on the growth and yield of gerbera in hydroponic open system

Field: Agricultural and Biological Sciences (Life Sciences)

Gerbera (Gerbera jamesonii) is one of the herbaceous plants with colorful and beautiful flowers that are used as cut, pot and garden flower. Various planting beds around the world is used for growing gerbera such as perlite, rock wool, vermiculite, sand, coconut fibre (coco peat), expanded clay, organic substrates, compost cow, zeolite, pumice, sand etc. reported by Khalaj (5) and Fakhri et al. (4). Soil-less cultures have been successfully used for several decades with the aim to intensify production and reduce cost of cultivation (Maloupa et al., 6). Peat is the most widely used substrate for potted plant production in the nurseries and accounts for a significant portion of the materials used to grow potted plants (Marfa` et al., 8; Ribeiro et al., 15). Since the last few years, coco peat, also known as coir dust has been considered as a renewable sphagnum peat substitute for the use in horticulture (Yau and Murphy, 19; Pisame et al.,13). Perlite has been widely used in soil-less cultures too. Perlite, an alumino-silicate of volcanic origin, is rather inert (low buffering and cation exchange capacities of 0-1 mg l-1). In general, it has a closed cellular structure, with the majority of water being retained superficially and released slowly at a relatively low tension, providing excellent drainage of the medium and aeration of rhizosphere (Maloupa et al., 6). The objective of this study was to determine the effect of different substrates on growth and yield of gerbera under an open soil-less production system. This experiment was carried out as Randomized Complete Block Design (RCBD) with 14 treatments and three replications for study on the effect of different substrates on growth and yield of gerbera over a period of 6 months as (v/v) : T0 = fine sand, T2 = peat + fine sand (25% + 75%), T3 = peat + fine sand (50% +50%), T4 = perlite + peat (75% + 25%), T5 = perlite + peat (50% + 50%), T6 = perlite + peat (25% + 75%), T7 = perlite + peat + expanded clay (25% + 70% + 5%), T8 = perlite + peat + expanded clay (50 %+ 25%+ 25%), T9 = perlite + peat + expanded clay (25%+ 50% + 25%), T10 = perlite + expanded clay (50% + 50% , T11 = coco peat, T12 = coco peat + perlite (75 %+ 25%), T13 = coco peat + perlite (50% + 50%), and T14 = coco peat + perlite + expanded clay (50% + 25% + 25%). The different physical properties of the media tested are given in Table 1. Plants were fertilized with a same nutrient solution in all the treatments. Sand, perlite and expanded clay were used with 0.5-1.0, 1.0-2.0 and 3.0-5.0 mm in diameter, respectively. The greenhouse temperature and relative humidity were 18-280C and 50-70% and the intensity ranged from 23,000-25,000 (lumens/ m2). Gerbera plants were transplanted in 4 l capacity pots. They were irrigated 3-4 times daily. Electrical conductivity and pH of water (nutrient solution) was 5.5-6.5 and 1.5-2.0 dS/m, respectively. In a period of six months, different flower characteristics were measured such as flower number, flower stem height, flower disc diameter, stem diameter, stem neck diameter and vase-life. Standard procedures were followed to collect the data for growth and flowering parameters. The data collected was analyzed statistically by using Duncan’s Multiple Range (DMR) test at 5% probability level and used to compare the difference among treatment means (Steel et al., 16). The selecting of media is based on many factors as existence; ease of use, cheap for producers. The different types of media can be used as peat and recently coco peat (coconut fibre), rock wool, vermiculite, perlite, expanded clay, pumice, sand etc. have been used in different proportions. In this experiment, based on various sources of external and internal reviews, common media used in gerbera cultivation were evaluated (Sindhu et al., 15; Khalaj, 5; Venezia et al., 18; Mascecarini, 9; Pisanu et al., 13). The results showed that T7 treatment, which includes a mixture of perlite + peat + expanded clay (25% + 70% + 5%) produced maximum flower numbers (10.33) against control comprising sand bed alone (3.77 flowers) (Table 2). The flower numbers of gerbera in T7 treatment could be due to the faster plant development and good root system and better physico-chemical properties of mixes. Growth medium is known to have a large effect on value of potted ornamental plants (Vendrome et al., 17). Cation exchange capacity (CEC) of substrate No. 7 was 80 Short communication