Ethylene positively regulates fruit growth. A, Cross-fertilization assay. Emasculated WT flowers were fertilized with WT or slein2-1 pollen. Conversely, WT or slein2-1 pollen was used to fertilize emasculated slein2-1 flowers. Each plant bears the same number of fruits. The 45-dpa fruits and statistics of fruit diameters were shown (n = 12, sd). B, Statistics of viable seed number of fruits harvested in (A). The seed number was determined at 55 dpa. For each genotype, n = 12. **P < 0.01, Student’s t test. C, Statistics of WT, slein2-1, sleil1 sleil2 sleil3/SlEIL3 sleil4 fruit diameter at different growth stages (10, 20, 30, and 40 dpa) with manual pollination. Each plant bears the same number of fruits. For each genotype, n = 12. **P < 0.01, Student’s t test. D, Expression data of SlEIN2, SlEIL1, SlEIL2, SlEIL3, and SlEIL4 in pericarps at different growth stages (0, 5, 10, 20, and 30 dpa, MG). Data were extracted from the Tomato Expression Atlas platform (https://tea.solgenomics.net/). RPM, reads per million mapped reads. E, Histological analysis of transverse sections of 5-dpa WT and slein2-1 fruit pericarps, and statistics of their respective number of cell layers (n = 10, SD). Student’s t test. Bar = 20 μm. F, GUS staining analysis of the auxin-responsive promoter DR5 fused to the GUS reporter gene (DR5:GUS) in WT and slein2-1 young fruits (1 and 3 dpa). Black arrowheads indicate pericarps. White arrowheads indicate seeds. G, Relative mRNA levels of three auxin-related genes (SlARF5, SlARF9, and SlGH3.2) and two cell cycle genes (SlCycB1.2 and SlCDKB2.1) in WT and slein2-1 young fruits (3 dpa). Error bars indicate sd (n = 3), **P < .01. Student’s t test. H, IAA content in WT and slein2-1 young fruits (3 dpa). Error bars indicate sd (n = 3), **P < 0.01, Student’s t test. I, Statistics of WT and slein2-1 fruit diameter at 30 dpa and the diameter of 30-dpa slein2-1 fruits treated with 20-μM 2,4-D once a week after fertilization. Error bars indicate sd (n = 12), **P < 0.01, Student’s t test.