Table 3. Watermelon reference genes ranked according to their expression stability as determined by NormFinder in different sample sets.

All samples	Stability value	Organ and tissue	Stability value	Abiotic stress	Stability value	Biotic stress	Stability value
ClYLS8	0.386	ClYLS8	0.353	ClUBCP	0.277	ClCAC	0.064
ClUBCP	0.492	ClPP2A	0.479	ClRPS2	0.340	ClTUA	0.271
ClPP2A	0.572	ClUBCP	0.535	ClTUA	0.432	ClRPS2	0.308
ClEF1α	0.652	ClPTB	0.713	ClLUG	0.473	ClYLS8	0.368
ClCAC	0.659	ClACT	0.759	ClYLS8	0.515	ClEF1α	0.403
ClPTB	0.706	ClEF1α	0.766	ClACT	0.569	ClUBC2	0.649
ClTUA	0.731	ClTUA	0.829	ClCAC	0.574	ClUBCP	0.660
ClACT	0.770	ClCAC	0.834	ClPTB	0.650	ClSAND	0.684
ClLUG	0.874	ClSAND	0.951	ClIDH	0.664	Cl18SrRNA	0.767
ClSAND	0.898	ClLUG	1.020	ClPP2A	0.682	ClPP2A	0.802
ClIDH	0.967	ClGAPDH	1.062	ClEF1α	0.692	ClPTB	0.849
ClGAPDH	1.050	ClIDH	1.179	ClSAND	0.949	ClIDH	0.958
ClRPS2	1.103	Cl18SrRNA	1.218	ClGAPDH	0.970	ClLUG	0.999
Cl18SrRNA	1.247	ClUBC2	1.364	Cl18SrRNA	1.196	ClACT	1.164
ClUBC2	1.467	ClRPS2	1.438	ClUBC2	1.898	ClGAPDH	1.265