Table 1. Pummelo S-RNases in F1 progenies segregate in a gametophytic manner.

Segregation analysis of S-haplotypes of F1 progenies of pummelo accessions for pollinations in half- and fully-compatible combinations were assigned using PCR (see Fig. 1f). Outcomes show segregation ratios as expected for a GSI system.

Phenotypea	Genetic cross	No. of progeny	Possible genotypes	Observed ratiob	Expected ratioc	Chi square	P-value
Fully-compatible	SJ (S5S6) × ST (S1S2)	77	S1S5 : S2S5 : S1S6 : S2S6	22:17:15:23	1:1:1:1	2.32	0.51 (N.S.)
					1:1:1:1	2.32	0.51 (N.S.)
Half-compatible	SJ (S5S6) × WB (S2S5)	118	S5S5 : S5S6 : S2S5 : S2S6	0:0:56:62	0:0:1:1	0.31	0.58 (N.S.)
					1:1:1:1	113.53	1.54E-25**
	WB (S2S5) × SJ (S5S6)	59	S2S5 : S5S5 : S2S6 : S5S6	0:0:34:25	0:0:1:1	1.37	0.24 (N.S.)
					1:1:1:1	61.75	2.49E-13**
	HB (S2S7) × ST (S1S2)	115	S2S2 : S2S7 : S1S2 : S1S7	0:0:53:62	0:0:1:1	0.7	0.4 (N.S.)
					1:1:1:1	116.41	4.58E-25**
	ST (S1S2) × HB (S2S7)	42	S1S2 : S2S2 : S1S7 : S2S7	0:0:21:21	0:0:1:1	0	1.0 (N.S.)
					1:1:1:1	42	4.01E-09**
	GX (S8S9) × SU (S2S8)	76	S8S9 : S9S9 : S2S8 : S2S9	0:0:39:37	0:0:1:1	0.05	0.82 (N.S.)
					1:1:1:1	76.11	2.10E-16**
	GB (S1S3) × MD (S3S5)	113	S1S3 : S3S3 : S1S5 : S3S5	0:0:62:51	0:0:1:1	1.07	0.3 (N.S.)
					1:1:1:1	115.14	8.58E-25**

^aThe pollination phenotype was determined by aniline blue staining (see Fig. 1a-d).

^bThe S-genotype ratios observed in all of the progeny.

^cThe upper segregation ratio is expected from a gametophytic self-incompatibility (GSI) system; the lower is expected from simple Mendelian inheritance. All crosses with parents sharing an S-RNase haplotype show a result consistent with GSI, with a non-significant (N.S.) Chi square for this prediction and a highly significant difference (**) for the lower segregation ratio. These data provide clear evidence that pummelo S-RNases segregate with the S-locus in a GSI manner.