TABLE 1

Genetic analysis of cim mutants

16 cimsaM1bLuc in F1cF2 (+:−)dχ2eChromosome
Mutants described in this study
cim536Yes57:251.32 (P > 0.2)2
cim615Yes40:202.22 (P > 0.1)1
cim72YesNDf
cim893Yes58:160.45 (P > 0.5)
cim998No33:990 (P > 0.95)
cim10107Yes31:110.03 (P > 0.95)5
cim11115Yes43:120.30 (P > 0.8)1
cim12124Yes34:215.1 (P > 0.01)g
779h168Yes47:6055.1g
cim13164Yes33:193.69 (P > 0.05)
cim14155Yes35:110.03 (P > 0.95)
Mutants not further analyzed
217NoND
11i36Yes87:350.89 (P > 0.4)
818YesND
36716YesND
67191Yes28:229.6 (P > 0.01)g
714121Yes15:50 (P > 0.95)
741132Yes22:188.53 (P > 0.01)g
  • With 250,000 M2 plants out of 168 M1 pools (containing 50 M1 plants), the coverage in the M2 can be calculated with the formula P = 1 − (f)n, with P, the probability to detect a recessive homozygous mutation in the M2; n, the number M2 plants screened per M1 plant = 250,000/168 × 50 = 29.7; f, the theoretical fraction of M2 plants that do not show a mutation present in one of the proposed effective two-germ cells of a M1 plant = 1 − 1/8. P yield thus to P = 1 − 0.875297 = 98.1%.

  • a Identification number of cim mutant. A mutant was retained when the luciferase level was induced at least 10-fold over background level (which was at 200 cpm, integrated over 10 min). In cases where macroscopic injuries were visible, the plantlet was discarded.

  • b M1 lot from which the mutant originated.

  • c Luciferase activity in F1 of backcrosses to the 6E line at least five times above background; due to incomplete penetrance of the mutant phenotype, the percentage of plants in the F1 populations expressing the PR1/luciferase gene varied between 10 and 100%.

  • d Segregation ratios of luciferase expressing to non-expressing plants in the F2 generation of a backcross to the parental PR1/luc line.

  • e χ2 and probability of the observed difference to the expected 3:1 (expressing to nonexpressing) segregation ratio for a single dominant mutation.

  • f ND, not determined.

  • g Hypothesis of a 3:1 segregation rejected.

  • h Lesion mimic.

  • i cim 11 originated from the same M1 seed lot as cim5; they may be identical.