여름무우 品種改良에 있어서 單株系統法의 利用 硏究(1) F₁品種의 兩親系統 育成法으로서의 可能性 檢討

Studies on Applying the Single Seed Descent Method for Breeding a Summer Variety in Radish, Raphanus sativus L. (Ⅰ) Consideration as a Means of Developing Inbred Lines of Fi Hybrids

The single seed descent method was tried for developing parental inbreds of an F₁ hybrid variety for summer production of radish. A double cross population was provided by crossing a virus resistant plant of the variety Minowase to the commercial true variety Yonghyeon which was mild-resistant, and then to the commercial F₁ variety Taebaeck which was very susceptible to virus disease. Fifteen percent out of 185 inbreds at the F₅ generation was resistant or tolerant to virus and soft rot diseases. At least three different self-incompatibility alleles were identified to be involved in the 5 lines selected finally and S-allele segregation was detected in three inbreds out of these selections. Heterosis of F₁ hybrids between selections seemed to be enough to meet the breeding goal. Consequently, it is considered that the single seed descent technique can be applied to developing inbred lines for an F₁ hybrid suitable for summer production of radish, which is an out-crossing crop, on low land.