Study on Graft Compatibility of Plants among three Selected Cucurbits

The research was conducted using three selected cucurbits such as cucumber (Cucumis sativus L.), bottle gourd (Lagenaria siceraria (Mol.) Standl. ) and bitter gourd (Mormodica charantia L.), to evaluate on the yield of grafted and non-grafted cultivated plants in completely randomized design (CRD). The seeds of cucumber, bottle gourd and bitter gourd were suggested to use in this experiment owing to the germination rate of above 70 %. In grafting, the graft compatibility of bottle gourd as a stock was the most exceptional for cucurbits and the survival rate is 26.5%. When compare the vegetative and reproductive growth of grafted and non-grafted of three cucurbits: cucumber, bottle gourd and bitter gourd. The grafted plants had maximum leaf area, female and male flowers, and fruit yield. The fruit weight of grafted plants was also superior to non-grafted plants. It was therefore suggested to use the grafted cucurbits for yield improvement. Introduction Cucurbits including in the family Cucurbitaceae had 118 genera and 825 species, and these plants are distributed in tropical and subtropical regions of the world (Jeffery et al., 1990). Among 118 genera, four have been recognized as of great economic importance: Citrullus, Cucumis, Cucurbita and Lagenaria. Cucumber (Cucumis sativus) is of Asiatic origin and probably of Indian origin and was domesticated around 1500 BC (Pitrat et al., 1999). Cucurbits are an important part of the human diet (FAO, 2006). The germination of typical dicot, the cucurbits, is epigeal and require relatively high temperature for germination. Generally cucurbits will not germinate in soil temperature below 17 19 °C. Cucumber, bottle gourd and bitter gourd may be grown on trellised, if it is not they tend to vine and sprawl out vigorously in the garden. Moreover, the use of trellises is to overcome the space problem (The Gardener, 1996). The main advantage of grafting is disease-resistant (Core, 2005). Grafting is the joining the two plant parts together such that they will unite and continue their growth as one plant. Grafting with detached scions has been practiced for thousands of years. It was used by the Chinese before 2000 B.C and spread to the rest of Eurasia and the practice was almost common in ancient Greece (Garner, 1988). Grafting of cucurbits is practiced to acquire the disease and drought resistant plants, and yield improvement of such crops. Grafting has become a routine technique in continuous cropping systems in many parts of the world. It was the first introduced in Korea and Japan during the late 1920s by grafting watermelon onto bottle gourd rootstocks to address the problems of declining yield due to soil borne disease in plants (Garner, 1988). It is estimated that more than half of the world's watermelons and cucumbers are produced in China and more than 90% of these are grafted. In grafting, the rootstock is important effects in plant growth, yield, and fruit quality (Garner, 1988). Grafting, which does not require major adaptations in farming practices, has been rapidly adopted y the cucurbits growers in many countries. Grafting of cucurbits for the local market is also rapidly developing (Lee, 1994). In many countries, yield increase has been reported. The average yields of grafted plants were much higher than the yields of the nongrafted plants (Lee, 1994). Regarding to the above facts, the study is aimed to record the seed germination rate of three selected cucurbits, to study the process of grafting, to examine the graft compatibility of cucurbits based on the survival rate of plants and to observe the growth of grafted cucurbits. Dagon University Research Journal 2014, Vol. 6 144 Materials and Methods Germination, grafting of curcurbits such as local and F1 varieties of Lagenaria siceraria L. , Cucumis sativus L. and Momordica charantia L. and field performance of grafted plants was carried out in Vegetable and Fruit Research Development Centre (VFRDC). Table 1. Name, definition and source of rootstocks and scions Plant Species Definition Source Rootstocks L. siceraria (Mol.) Standl. Local VFRDC L. siceraria F1 VFRDC Scions C. sativus L. Local VFRDC C. sativus F1 VFRDC L. siceraria (Mol.) Standl. Local VFRDC M. charantia L. Local VFRDC Grafting Methods Peg (or) hole insertion grafting technique (HIGT), and splice grafting technique (SGT) were used in this experiment. Preparation of Seedbed and Seed Germination In this experiment, 22.2 cm x 24.75 cm size polyethylene bags and the plastic trays with 104 plots were used for growing of stock and scion plants. The polyethylene bags and plastic trays containing the mixture of sand and vermicompost (10: 1) was prepared before sowing the seeds. One seed was sown in one polyethylene bag and also in a plot of tray. The bags and trays were set up under the shade. Peg (or) Hole Insertion Grafting Technique (HIGT) The stem of stout, straight and big diameter of the stock plants was chosen from the germinated plants. The first node between the cotyledons was straight cut by using a razor blade. Then the bamboo stick was inserted at the middle of the node to make a small hole for inserting the scion. The diameter of scions must be smaller than the stock. The slant cut was made 1 cm above cotyledons of straight and smaller diameter of scions. The cut end of scion was carefully inserted into prepared stock. Splice Grafting Method (SGT) This method was applied for the rootstock and scion of nearly the same diameter. The stem of the stock with one cotyledon was slant cut using a razor blade. The hypocotyl of the scion was also slant cut and then the cut ends of the stock and scion were grafted and the grafted union was firmly sealed with tape. Grafting of Three Cucurbits In this experiment, seven treatments with 60 replicates were set up in Completely Ramdomized Design (CRD). The distance between individual bag and between rows is 2.5 cm. The treatments are as follows. T1 Lagenaria siceraria (F1) x Cucumis sativus L. (Local) T2 Lagenaria siceraria (F1) x C. sativus (F1) T3 Lagenaria siceraria (Mol.) Standl. (Local) x C. sativus L. (Local) T4 Lagenaria siceraria (Mol.) Standl. (Local) x C. sativus (F1) T5 Lagenaria siceraria (Mol.) Standl. (Local) x L. siceraria (Mol.) Standl. (Local) Dagon University Research Journal 2014, Vol. 6 145 T6 Lagenaria siceraria (Mol.) Standl. (Local) x M. charantia L. (Local) Data Collection The experimental data were recorded once a week. The germination rate, survived and dead plants were recorded by Soupe (2009) and the leaf area method were recorded by Blanco and Folegatti (2005). The recorded data were analyzed using the following the formula: Germination Rate (%) = Seeds Sown Total Seeds Germinated x 100