These experiments were carried out to study the inheritance of male sterility in carrots, Daucus carota L, and to seek its utilization in hybrid seed production.
The results obtained are summarized as follows;
1. Two of twelve hypotheses tested on the inheritance of male-sterility in carrots were satisfactory: the one that male-sterility in carrots is controlled by a cytoplasmic factor, two duplicate dominant nuclear genes and two complementary dominant fertility restoring nuclear genes, and the other by a cytoplasmic factor, two duplicate nuclear genes(one recessive, one dominant) and two complementary dominant fertility restoring nuclear genes.
2. As segregation ratios of 25 among 104 F₁ combinations in 1975 experiment were 15:1, so the first hypothesis is more reasonable than the latter.
3. High frequencies of M.S. plants in F₁, BC₁ F₁ and BC₂ F₁ generations for 3 years respectively imply that restorer genes do not function in the materials tested.
4. Genetical compositions of recurrent parents are probably (N) A……or (N)--B-, therefore it is possible to attain maintainer lines.
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