The pruning and fruiting in vertical culture of melon(Cucumis melo L. var inodorous Naud) and the effect of NaCl on melon fruit quality

• Main Authors: Shih-Min Lin, 林世旻
• Other Authors: 宋妤
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/44999462114574318971

碩士 === 國立中興大學 === 園藝學系所 === 99 === For the production of high-quality melons, growing plants in an insect-proof greenhouse using a vertical cultivation system and supplementing with nutrient solution, This study investigated the factors that may improve melon quality and production, including the pruning method, number of leaves to be retained, location of the fruit setting position, and use of NaCl to adjust the concentration of the nutrient solution. In 2–3 weeks, the total leaf growth of the ‘Summer Phoenix’ muskmelon had the highest fresh dry weight, leaf area, chlorophyll content and soluble sugar content. In 5–6 weeks, the 10th leaf growth showed a significant reduction in chlorophyll, soluble sugar content and △Fv/Fm, while the 20th leaf growth did not exhibit this phenomenon. From 2–14 days after fruit setting, the fruits showed rapid enlargement, and the fruit weight reached more than 1000 g. Two weeks before harvest, the total soluble solids increased greatly in the fruits, reaching above 13.7 °Brix in mature fruit. Comparing the growth of ‘Golden Lady’ and ‘Summer Phoenix’ muskmelons using different cultivation methods, including vertical one-branch pruning, vertical two- branch pruning or creeping cultivation, the results showed that the ‘Golden Lady’ under creeping cultivation had a significantly greater plant height and leaf area (241.8 cm and 6319 cm2, respectively) than that cultivated vertically. The three cultivation methods had no differing effects on plant growth for the ‘Summer Phoenix’ melon. Creeping cultivation resulted in the greatest fruit size for both ‘Golden Lady’ and ‘Summer Phoenix’, which was 1433.9 g and 1728.6 g, respectively. ‘Golden Lady’ with vertical one-branch pruning cultivation had a total soluble solids of 15.7 °Brix, which was higher than that produced by vertical two-branch pruning or creeping cultivation (15.0 and 14.2 °Brix, respectively). In terms of shade, at the fruit position, the upper leaves had no significant shading effect on the lower leaves with the creeping cultivation method, while for the ‘Summer Phoenix’ with the vertical cultivation methods, the PPFD and ETR increased significantly with leaf node position. This suggest that the upper leaves had a shading effect on the lower leaves, and the PPFD and ETR of the lower leaves decreased by 500 and 80 μmol m-2s-1, respectively. To compare the effects of different trimming methods on fruit growth, ‘Autumn Phoenix’, ‘Summer Phoenix’, ‘Golden Lady’ and ‘Autumn Sweet’ muskmelons were used different trimming methods that left 9, 12 or 15 leaves remaining above the fruit set position, with the branch topped. The results showed that the plant height and the total leaf area of the leaves above the fruit set position both increased with an increasing number of leaves remaining above the fruit set position. The plants with 12 or 15 leaves remaining above the fruit set position had the highest sugar content. ‘Autumn Phoenix’ with 12 leaves remaining exhibited a significantly higher fruit weight and flesh thickness, at 738.3 g and 2.90 cm, respectively. ‘Summer Phoenix’ and ‘Golden Lady’ had the best fruit growth with 9 leaves remaining, followed by 12 and 15 leaves remaining. For ‘Autumn Sweet’ with 12 and 15 leaves remaining above each fruiting node, the fruit weight was 897.3g and 880.3 g and the total soluble solids was 13.9 and 14.6 °Brix, respectively. During the fruit growth period, ‘Autumn Phoenix’ and ‘Autumn Sweet’ muskmelons with 12 leaves remaining above each fruiting node maintained a higher △Fv/Fm, which was around 0.7. To compare the effect of fruit set position on fruit growth, using ‘Golden Lady’, ‘Summer Phoenix’, ‘Golden Honey’ and ‘Autumn Sweet’ muskmelon plants, the fruit setting position on the primary branch was kept at node 9, 12 or 15, retaining 12 leaves above the nodes. The plant height of all four cultivars increased as the fruit set position increased, significantly increasing the number of days from planting to flowering. With the exception of ‘Summer Phoenix’, the fruit size increased with increasing fruit set position in all 3 cultivars. With the fruit set position at node 15, ‘Golden Lady’ had the highest fruit weight, length and flesh thickness, of 1167.4 g, 14.7 cm and 3.47 cm, respectively. These values were significantly higher than those resulting from a fruit set position at nodes 9 and 12, while the fruit sugar content did not differ significantly between different fruit set positions. ‘Golden Honey’ and ‘Autumn Sweet’ had similar results to those for ‘Golden Lady’. However, ‘Summer Phoenix’ with the fruit set position at node 9 had the largest fruit size, while with the fruit set position at node 15, it had a higher total soluble solids of 13.8 °Brix. In ‘Golden Lady’ and ‘Autumn Sweet’, as the fruit set position increased, the carbohydrate content in the leaves increased. The soluble sugar level synthesized by the 10th leaf of the plant with the fruit set position at node 15 was higher than that of plants with the fruit set position at nodes 12 and 9, which was 5.32, 4.55 and 4.29 mg/g DW, respectively. The results were positively correlated with fruit size. To investigate the effect of the concentration of the nutrient solution, the EC value of the nutrient solution was adjusted to 2, 5 and 8 ds m-1 (EC 2, 5 and 8) using NaCl, and the solutions were used to treat ‘Summer Phoenix’ and ‘Golden Lady’ muskmelon plants during the period of flowering to 15 days after fruit setting. In ‘Summer Phoenix’, The plant growth was not affected by EC 2 and EC 5 treated during the flowering period. In ‘Golden Lady’, The plant growth of EC 2 and EC 8 treatment was poor. In both cultivars, the leaf △Fv/Fm decreased as the EC value of the nutrient solution increased. EC5 treatment had no effect on the plant growth of ‘Golden Lady’ during flowering or 15 days after fruit setting, while the treatment did improve the fruit quality. EC 8 treatment reduced the chlorophyll content of the 10th leaf above the fruit set position in both cultivars, the values being 2.08 and 1.46 mg/g DW, respectively. In terms of fruit total soluble solids, EC 8 treatment increased the content of the ‘Summer Phoenix’ muskmelon to 13.8 °Brix, which did not differ significantly from that of the control, at 13.2 °Brix. In addition, EC 8 treatment and flowering-period EC 5 treatment significantly increased the total soluble solids of ‘Golden Lady’ to 15.4 and 16.0 °Brix, respectively. In conclusion, analysis of leaf photosynthesis revealed the selection criteria for a suitable cultivar, showing the factors that might affect physiological performance. Among the 4 cultivars, when vertical one or two-branch pruning methods were used, 12 leaves were retained above the fruit setting position, the fruit setting position was maintained at nodes 12–15 on the primary branch, and the nutrient solution was adjusted to EC 5 with NaCl, For producing the fruit with the highest quality.