Table 2.
Segregation of S genotypes in F1 progeny
| Genetic cross | No. of progeny | Possible genotypesa | Observed ratiob | Expected ratioc | χ2 value | P value |
|---|---|---|---|---|---|---|
| GY (S1S2) × GY (S1S2) | 530 | S1S1:S1S2:S2S2 | 0:274:256 | 0:1:1 | 0.6113208 | 0.434290956 |
| 1:2:1 | 247.91698 | 1.4639E−54 ** | ||||
| GY (S1S2) × ST (S1S2) | 309 | S1S1:S1S2:S2S2 | 0:150:159 | 0:1:1 | 0.2621359 | 0.60865653 |
| 1:2:1 | 163.8932 | 2.57658E−36 ** | ||||
| ST (S1S2) × ST (S1S2) | 0 | S1S1:S1S2:S2S2 | ||||
| ST (S1S2) × GY (S1S2) | 81 | S1S1:S1S2:S2S2 | 27:35:19 | 1:2:1 | 3.0740741 | 0.215017247 |
| 1:1:1 | 4.7407407 | 0.09344611 |
Segregation analysis of S haplotypes of F1 progeny of pummelo accessions from self- and cross-pollination experiments analyzed using PCR (Fig. 3D–F).
aThe observed genotypes are underlined.
bThe S-genotype ratios observed in all of the progeny.
cThe upper segregation ratio is that expected from a single genotype mutation model of the GSI system, while the lower segregation ratio is that expected from simple Mendelian inheritance. The pollinations that used pistils from ‘GY’ produced results that were consistent with the single genotype mutation model, with a nonsignificant chi-square value for this prediction and a highly significant difference (**P < 0.001) for the lower segregation ratio. These data provide compelling evidence that the mutation that promotes self-compatibility in ‘GY’ occurs on the pistil side.