Effects Of Deficit Irrigation On Development Of Muskmelon And Fruit Quality Grown In A Greenhouse

Traditional deficit irrigation consider more about the production and the high water production efficiency at a limited irrigation. Recent years peoples requirement of the quality of the fruit higher than years ago, melon as the important economic crops in facility agricultural, improvementit’s quality is very important. The effects of different drip irrigation water levels during productive growth stage on fruit development, water use effect, fruit production, quality and sensory experiences for muskmelon were studied in plastic greenhouse. And there were five different irrigation water levels relative to the percentage of field water capacity,85%-T85,75%-T75,65%-T65,55%-T55,45%-T45, respectively.1.The result showed that the fruit development generally divided into three stages and the finish of vertical diameter growth was ahead of transverse diameter. The first stage is10d after the pollination,at this time the growth rate of the fruit of Love net is7-13mm/d, the growth rate of the Elizabeth was3-9mm/d and the time could be15d in spring. it is key time of the fruit rapid expansion phase. The second stage was10-20d, at this time the growth rate of the fruit of Love net was1-4mm/d, amd the Elizabeth was1-2mm/d, it’s the fast growth stage. The third stage was slow growth stage, the love net was20-55d after the pollination, Elizabeth was20-35d after the pollination, in spring and autumn they were different and in spring the fruit growth rate was1.0mm/d, in autumn lower than0.5mm/d.Different water processing has different fruit growth rate, but it is usually T85> T75> T65> T55> T45, the fruit diameter growth rate gradually decreased as a resuit of the deficit time’s extending, and its growth rate accelerated after supplementary irrigation and faster than T85, which produced compensation effect. In the same growing period the serious the water deficit, the faster the fruit diameter growth when supplementary irrigation. but if the deficit last a long time, the compensation effect is not obvious, fruit diameter decreased as the reduce of irrigation amount. Considering the influence of irrigation water on fruit development, T65-T75would be better for the reproduction growth of melon inside plastic greenhouse.2. The fruit yield and the weight of single fruit reduced with the decreasing of irrigation quality. There are no significicant difference of T75and T85in single fruit weight. Compared with T85, the weight of single fruit of T65has remarkable difference in autumn but no obvious difference in spring, and it’s yield reduced3% -7%. The yield of T55and T45decreased16%-30%compared with T85. Water use efficiency of the four groups are all higher than T85, but T45or T55were not the hightest one. The fruit diameter, fruit cavity diameter, fruit wall thickness and flesh thickness were reduced with the water amount reduce, and T45was cbviously decilin. In addition the yield and WUE of spring were1.7and1.8times highter than autumn, consider the WUE and the yield, T65-T75would be the best for the reproduction growth of melon inside plastic greenhouse.3.T55、T65and T75was better than others at quality, the contented of TSS was increased about18.2%, and the soluble sugar wase increased31.7%compared with T85. Soluble protein of T65and T75were increased39.7%compeared with T85and better than other treatments. the content of Vc showed no significant regularity of love net, but the less water amount the higher conten about Elizabeth, and in Elizabeth it could increaced264%. But excessive water deficit would reduce the content of Vc in autumn.During the spring and autumn use Gsa chromatography measured the sugar and acid of melon showed that, in muskmelon the sugar is given priority with sucrose, and69%-86%are sucrose(spring could be more than autumn), the proportion would be increased as the water amount declined. In spring the total sugar and sucrose of T65were higher than other treatments, the fructose and glucose of T85were highter,and T75was higher in citric acid. In autumn the contenct of the three sugars higher in T65and T75. so in pring it can be T65and in autumn it can be T65-T75as the irrigation scheduling of the reproductive stage of melon.The aromatic compounds of melon fruit were analyzed using gas chromatoraphy-mass spectrometry(GC-MS), it shows that there are65kinds of aroma substances in love net, and esters has48kinds as the main aroma substances by78.1%-91%of the peak area. T55has the most amount of the aroma and T75、T65take the second place, but T75has the most amount of esters by13.0%compared with T85. T55has the most amount of aldehydes and alcohols by87.7%compared with T85. so water deficit increased the amount and the kinds of aroma substunce,especialy the aldehydes and alcohols.