Abstract: Abstract: Deficit irrigation is an effective method for water resource saving while maintaining crop yield. This study aimed to investigate effects of different irrigation low limits on yield and growth of self-rooted and grafted muskmelon in greenhouse. The experiment was conducted in 2015 in a plastic greenhouse of Huazhong Agricultural University, Wuhan, China (114?22?E, 30?29?N). The soil was clay-loam with field water holding capacity (FC) of 32.6%. Three different drip irrigation low limits were designed based on FC including 45%FC, 65%FC and 85%FC during the reproductive stage of self-rooted and grafted muskmelon and for all the treatments the irrigation lower limit in the vegetative growth stage was kept as 65%FC. There were a total of 6 treatments, and each replicated 3 times. The muskmelon species was Elizabeth with a growing period of 90 d. The white seed pumpkin was used as the graft stock for the grafted muskmelon treatments. During the experiment, the measurements were leaf SPAD, plant height, stem diameter, leaf area, aboveground dry matter, root dry matter, yield and weight per fruit. The root-aboveground dry matter ratio and irrigation water use efficiency was calculated. The results showed that: 1) the plant height and stem diameter became different after 9 days of transplanting, and kept increased. The plant height of the self-rooted muskmelon was higher than that of the grafted muskmelon but the stem diameter of the former was lower than that of the latter; 2) The leaf area of grafted muskmelon under deficient irrigation increased faster than that of the self-rooted muskmelon. In the vegetative growth stage, due to the same irrigation low limit, the SPAD values of the most treatments did not show significant difference. In the reproductive stage, the different irrigation low limits caused different SPAD values, which decreased with reduction of irrigation. Under the 45%FC treatment, the grafted muskmelon had higher SPAD value than the self-rooted muskmelon. With decreasing irrigation low limits, the root and aboveground dry matter decreased and the root-aboveground dry matter ratio increased. The 65%FC treatment had significantly higher root dry matter than 45%FC, but was similar with the 85%FC treatment. The aboveground dry matter of the grafted muskmelon was significantly higher that of the self-rooted muskmelon under the treatments of 45%FC and 85%FC; 3) The yield was ordered by 85%FC for the grafted or self-rooted muskmelon, 65%FC for the grafted muskmelon, 65%FC for the self-rooted muskmelon, 45%FC for the grafted muskmelon, and 45%FC for the self-rooted muskmelon. Under the deficient irrigation, the 65%FC for the grafted muskmelon was the highest. Compared with full irrigation (85%FC), the 65%FC for the grafted muskmelon had 17.3% and 21.6% lower yield than the self-rooted and grafted muskmelon, however had 30.5% and 37.7% higher water use efficiency than the grafted and self-rooted muskmelon.