TABLE 1

The frequency of recombinant chromosomes in the BC2 Population

Single recombinantsDouble recombinants
Non recombinantsNon-
NOR arm
NOR armOne per
arm
Two in
non-NOR arm
Observed nos.595318153
7118
Expected nos. (no chromatid interference)54.7652.821.219.240
7419.24
Expected nos. (chromatid interference)35.5112.70
  • Shown are the observed numbers of nonrecombinant and recombinant chromosomes in the BC2 population of 148 plants and the arm locations of the recombination site. Also shown are the expected numbers of nonrecombinant and recombinant chromosomes with a BC2 population of 148 plants based on the observed frequencies of rod and ring bivalents without and with complete chromatid interference. An example of expected numbers calculation for single recombinants (no chromatid interference) is as follows:

    1. Rods:rings, 48%:52%.

    2. Rods = 50% nonrecombinants and 50% single recombinants (see Figure 1). Therefore in total population 24% = single recombinants.

    3. Rings = 25% nonrecombinants, 50% single recombinants and 25% double recombinants (see Figure 1). Therefore in total population 26% = single recombinants.

    4. 24% + 26% = 50% single recombinants = 74 plants out of the 148.