Effect of Mycorrhiza, Fertilizers and Planting Media on Rock Melon (Cucumis Melo Linn Cv. Glamour) Growth Using The Canopytechture Structure

: Rock melon (Cucumis melo Linn), one of the most popular and delicious fruits of Malaysia has great potential for commercial development. Currently, rock melon is most widely cultivated under rain shelter structure using soilless culture. This study aimed to determine the effect of mycorrhiza, various fertilizer and planting media applications on growth performance of rock melon (Cucumis melo Linn cv. Glamour) in open area. The experiment comprised the following treatments: T1 = Medium A - Mycorrhizal + Inorganic fertilizer, T2 = Medium A + Mycorrhiza + Organic fertilizer, T3 = Medium A + Mycorrhiza + Inorganic fertilizer, T4 = Medium A - Mycorrhizal + Organic fertilizer, T5 = Medium B + Mycorrhiza + Organic fertilizer, T6 = Medium B + Mycorrhiza + Inorganic fertilizer, T7 = Medium B - Mycorrhiza + Organic fertilizer and T8 = Medium B - Mycorrhiza + Inorganic fertilizer. Medium A consisted of Peat moss + Perlite + Vermiculite while Medium B comprised Peat moss + Perlite + Vermiculite + Top soil. A randomised complete block design experiment with three replications was conducted at the Horticulture Research Centre plot, MARDI, Serdang. Different types of fertilizer, planting media and applications of arbuscular mycorrhizal had effects on fruit production and yield of melon as compared to control (T1). Maximum and significant yield of melon was from T6 plants. Furthermore, the maximum fruit weight and total soluble solids of 1350 g and 14.25 °Brix, respectively, were from T6 treated plants and the minimum was from T4 (717 g and 10.17 °Brix, respectively). The presence of the indigenous arbuscular mycorrhizal inoculums in planting media was successful in colonizing plant roots, resulting in better plant growth and significantly enhanced yield of rock melon. This study suggested the possibility of applying moderate combinations of planting media with mycorrhiza in producing good quality and high yield of rock melon.


Introduction
Horticultural cultivation is becoming widespread in urban areas of Malaysia. Growing climbing vegetables vertically in pots using a simple structure called Canopytechture ( Figure  1) has been developed by Malaysian Agricultural Research and Development Institute (MARDI). The Canopytechture is a multi-purpose supportive support system for cultivating climbing vegetables and fruit trees. It is a specially designed structure to allow the plants to twist, cling and grow vertically. This structure has a special hexagonal shade frame measuring 150 centimeters in diameter and is located on a support pole with a height of 180 cm. Through training and bending process, vegetables or fruit trees can grow vertically and produce fruits that hang in the special section. For urban agriculture, this simple multipurpose support structure is very practical to be applied with a self-watering container (SWC) or regular pot for cultivating climbing vegetables such as angled gourd, bitter gourd, cucumber and pumpkin as well as fruits such as grapes, passion fruit and melons. Its use can help the landowners to grow crops in limited spaces. In addition to crop yields, Canopytechture can also give aesthetic impact and become a therapeutic element in the site. Increased use of fertilizers can affect both human and the environment. A reduction of fertilizer input together with selecting suitable combinations of planting media will better adapt to these constrains thereby increasing the sustainability of crop production.
Arbuscular mycorrhizal fungi (AMF) can be integrated in soil management to achieve low-cost sustainable agricultural systems [1,2]. Mycorrhizal fungi occur in most of the soils and colonize roots of many plant species. Mycorrhiza are structures resulting from the symbiosis between these fungi and plant roots, and are directly involved in plant mineral nutrition. The symbiotic root-fungal association increases the uptake of less mobile nutrients [2,3]. AMF can also benefit plants by stimulating the production of growth regulating substances, increasing photosynthesis, improving osmotic adjustment under drought and salinity stresses and increasing resistance to pests and soil borne diseases [4]. These benefits are mainly attributed to improved phosphorous nutrition [2,5]. Most horticultural and crop plants establish the symbiosis with AMF. Although the mycorrhizal potential of the symbiosis to improve horticultural production is recognized [2,6], it has not been implemented under field conditions, integrating this biotechnology in large horticultural production systems [7]. Melon (Cucumis melo L.), a common fruit in the South East Asia region, forms the arbuscular mycorrhizal symbiosis [8], with a positive effect on plant growth [2,7] under controlled experimental conditions.
Rock melon (Cucumis melo Linn), a common fruit in South East Asia region, forms the arbuscular mycorrhizal symbiosis [8], with a positive effect on plant growth [2] under controlled experimental conditions. Cucurbitaceae family crop responds well to an increased fertilization [2,9] reported that the amendment of soil with vermicompost in quantities ranging from 10 to 50% significantly increased dry matter yields of cucumber plants, compared to treatments where soil was not amended. Mycorrhizal inoculation of cucumber could increase seedling quality and reduce the quantity of fertilizer application, to achieve similar yields to non-inoculated plants [2,7,10,11]. In this work we attempted to find a niche for the production of mycorrhizal inoculated seedling with the objective of substituting partially or completely the fruit quality and yield application with mycorrhizal inoculation. We screened different combinations of planting media with and without mycorrhiza, assessing the effects on melon seedling growth and yield under field conditions.

Experimental Site and Growth Conditions
The experiments were conducted in an open area located at Horticulture Research Centre plot, MARDI, Serdang Selangor (2° 59' 51.4374" N 101° 41' 26.227" E / 2.997622° N 101.690619° E), with average minimum/maximum temperatures of 23.0°C -33.0°C ( Figure 2). Rock melon (Cucumis melo. L. cv. Glamour) seeds were sown in germination trays filled with peat and was placed in a growth chamber under controlled conditions for one week. At 7 to 10 days after emergence, uniform seedlings were selected and gently removed from the trays and transplanted into planting pots measuring 52 cm x 46 cm (width x height) which were complete with the Canopytechture structure. Plants were manually irrigated twice a day and kept well watered for a week until plant roots were well established (   Plants were subjected at two application of fertilizer types, organic and inorganic. The organic fertilizer was processed chicken dung at 300 g/plant, while inorganic fertilizer was NPK green and NPK blue at 50 g/plant. Data taken were plant height, vine length, number of leaves, number of nodes, stem diameter, fruit weight, fruit length, fruit diameter, total soluble solids, rind and flesh thickness.

Experimental Design and Statistical Analysis
The experimental design was a randomized complete block design (RCBD) with three replications. Analysis of variance (ANOVA) was performed using the procedures of the Statistical Analysis System [12]. The Least Significant Difference (LSD) was used for test of significance.

Determination of Yield and Fruit Quality
Total fruit fresh weight was recorded at the end of the growing season i.e. at 76 days after transplanting (DAT). In all treatments, only one fruit was borne per plant located between leaf number 7 to 13 or node 7 to 12. Total soluble solids (TSS) of rock melon from respective treatments were assessed at harvest, i.e. at 76 DAT. The TSS was determined on the juice extracted from the pericarp sliced from the equatorial region of the fruit using a hand held refractometer (Model ATC-1 Atago, Tokyo, Japan), with automatic temperature compensation.

Plant Height
Growth performance parameters evaluated showed statistical differences in rock melon plants following applications of different types of fertilizers, planting media and mycorrhiza. At 76 DAT, the maximum and significant on plant height was recorded from T6 plants (190.78 cm) while the lowest plant height was recorded from T4 plants (146.89 cm) at harvest (Figure 4).

Vine Length
Results obtained showed an increase on vine length with the similar trend according to the treatment tested. Vine length from T6 and T3 plants were 205.11 and 198.72 cm, respectively, higher and significantly different from T4 plants (157.61 cm) at 76 DAT ( Figure 5)

Number of Leaves
Leaf number also showed an increase with an increase in plant growth, with maximum and significant results obtained from T6 plants (31 leaves) at harvest (76 DAT). Again T4, T7, T1 and T8 plants showed the sequent least increase in total leaf number at harvest (Figure 6).

Number of Nodes
Number of nodes in T6 plants (30.50) was higher as compared to other treatments. Again the minimum number of node reading of 26.61 and 26.83 were from T4 and T7 plants, respectively ( Figure 7).

Effect of Type Fertilizers, Planting Medium and Mycorrhizal Application on Plant Growth
Fertilizers are essential for crop production since plants need them for growth, tissue expansion and yield production. Growth and yield of rock melon was significantly affected by However, results showed that almost all plants which were treated with mycorrhizal inoculations significantly had increased number of leaf, stem diameter, fruit weight, fruit length, fruit diameter, rind and flesh thickness and flesh thickness. Cagras [13] found that mycorrhizal inoculation of cucumber plants significantly increased leaf and shoot fresh and dry weight, root biomass and leaf area index. Lee and George [14] showed that mycorrhizal hyphae of G. mosseae had a significant contribution in the uptake of P, Zn and Cu by inoculated cucumber plants resulting in a increased concentration of those nutrients in the plant shoots. Wang [15] also showed an increased macro nutrient element uptake in inoculated cucumber plants.
Overall, T6 plants showed superior results as compared to other treatments in terms of weight, rind and flesh thickness of fruit. Inorganic fertilizer application enhances plant growth and yield because it is absorbed quickly by soil and plants. Therefore, farmers apply maximum amounts of inorganic fertilizers to their crops to achieve higher yield. As a result, excess inorganic fertilizers leach into the ground water and polluting it. To avoid this situation, a combination of inorganic fertilizer with biological ingredients is better to use in crop cultivation. Mycorrhiza is a type of organic fertilizer or bio fertilizer that creates mutual symbiosis between mycorrhizal fungi and higher plants. Mycorrhiza improves crop yield and increases the use of inorganic fertilizer by forming a bridge between the roots and the soil. It is indirectly enhancing the structure of the soil (planting medium) and improves air and water infiltration.

Conclusions
In conclusion, different types of fertilizers, planting media and mycorrhiza strongly affect vegetative and reproductive growth of melon. Results obtained from the current study indicates that both vegetative and reproductive growth of Cucumis melo plants were strongly affected by type of fertilizer, planting media and mycorrhiza applied. The overall rock melon plant yield changed and improved, although mycorrhizal inoculation was always beneficial for plant growth. The effects of the isolates were consistently the best; and gave good results, establishing good root colonization and increased rock melon yield, and could be integrated in rock melon production as an ecologically sound practice. We can conclude that rock melon plants readily establish the arbuscular mycorrhiza symbiosis with different planting medium types. The fungal species, planting media and fertilizer types increase plant yield and nutrient uptake, while inoculation always resulted in better plant growth. Seedling inoculation significantly increased rock melon survival at transplanting. The effects of other factors involved in plant growth such as weather conditions, seedling production, standardization of the inoculate, and crop management techniques need to be further studied in order to effectively integrate the mycorrhiza technology in horticulture production.