A second pair of duplicate factors for orange pericarp, that are not allelic to orp1 and orp2, have been found in M2 progeny from treatment of pollen with EMS. They differ from orp1 and orp2 in that they have separate distinguishable individual phenotypes. The double heterozygote selfed produces an ear segregating approximately 9 normal:3 small dented:2 collapsed nonviable:1 collapsed orange nonviable kernels.
The first of these factors, cp*-888A designated cp3, which appears as a variably collapsed floury non-pigmented nonviable kernel, segregates 3 normal:1 collapsed from a single heterozygote selfed. It has been located by a hypoploid test as proximal to the breakpoint of TB-1La but not uncovered by TB-1Sb. This places it between the breakpoint of these 2 translocations on chromosome 1.
The second factor, smk*-888C, designated mn4, segregates in heterozygote selfs as 3 normal:1 nearly normal slightly smaller dented viable kernels that germinate to produce a normal plant. This mutant has not been located to chromosome but it apparently segregates independently of cp*-888A. The double mutant phenotype, which occurs in a frequency of 1/16 from the double heterozygote selfed, is a slightly more collapsed nonviable kernel that has a distinctive orange pigmentation of the pericarp. The nature and relationship of the pigment to the indole-induced pigment from orp1 and orp2 has not been determined.
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