TABLE 1

Gametophytic reproductive barriers detected in the F2 population of a cross between Nipponbare and Kasalath

ChrPosition (cM)MarkerGenderAlternativeTJ (%)SSJ (%)I (%)H (%)χ2
1153.2 ± 1.2L819G1Z166.2 ± 0.433.116.950.09.8b
1154.7 ± 1.2L819G2Z133.3 ± 0.416.733.350.010.4b
362.3 ± 0.4C5825.8 ± 0.5D2.9a47.1a50.072.7b
417.4 ± 2.1C820G1Z38.5 ± 1.019.330.850.04.9
492.0 ± 1.4R738G230.0 ± 3.015.0a35.0a50.014.9b
545.7 ± 0.8C282AG133.2 ± 0.516.633.450.010.5b
553.2 ± 0.9R413G263.9 ± 0.632.018.050.07.2
595.7 ± 0.8C1402G234.2 ± 0.417.132.950.09.3b
595.8 ± 0.8C1402G167.6 ± 0.433.816.250.011.6b
733.2 ± 1.0V177G1Z227.6 ± 0.613.8a36.2a50.018.7b
740.1 ± 0.7R1488G2Z270.1 ± 0.535.1a15.0a50.015.0b
811.3 ± 1.7G278G176.1 ± 0.738.1a11.9a50.025.4b
820.3 ± 0.7R2367G225.1 ± 0.4D12.6a37.4a50.023.0b
834.4 ± 1.3V115G176.8 ± 0.7D38.4a11.6a50.026.7b
937.2 ± 2.2S266031.4 ± 1.315.734.350.012.9b
  • Chr, chromosome number; position, genetic distance from the short arm end of the genetic map; marker, closest marker name; gender, which gender the gametophytic barrier affects; G1 and G2, different gender gametophytic barriers on the same chromosome, e.g., when G1 is a male gametophytic barrier. G2 is a female gametophytic barrier on the same chromosome. However, the G1 barriers on the different chromosomes do not always affect the same gametophyte. Alternative, alternative types of barriers that could explain the allele frequencies with slight increment of variance. A single zygotic barrier could replace two pairs of barriers on chromosomes 1 and 7. TJ, the Japonica transmission rate through the gametophyte. SS corresponds to detection of segregation distorting reproductive barriers by simple scoring that counts major segregation distortion peaks beyond a certain range, 15.5–34.5% for homozygotes and 36.5–63.5% for heterozygotes (Harushima et al. 1996). D, barriers detected by simple scoring in a previous study (Harushima et al. 1996). J, I, and H are the respective expected frequencies of the Japonica homozygote, Indica homozygote, and heterozygote at each reproductive barrier, assuming that a single barrier is acting on the chromosome. χ2 for the segregation was calculated from J, I, and H for 186 plants.

  • a Values beyond the range.

  • b Highly significant distortion (χ2 > 9.2).