Quantitative inheritance in pea: lines with several mutant genes for the number of sterile nodes

The number of sterile nodes of 81 families of nonfasciated recombinants derived from hybrids between fasciated and nonfasciated lines, are compared with those of 17 control groups consisting of homozygous plants only. As the homozygous lines and recombinants usually show the low variation of only±1 sterile node with standard deviations (SD) of 0.25 to maximally 0.83, a minimum number of four genes was deduced from the 14 clearly distinguishable phenotypes obtained by recombination. Further recombinants with statistical mean values between the ones already obtained can possibly be derived from these fasciated mutants. A more optimistic prognosis (taking into account also the ratios of segregating to nonsegregating plants in random samples of several succeeding generations) would suggest 5 to 6 mutant genes, but some results point to a mutator gene repeatedly generating several phenotypes.