| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1993: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Because of the presence of the problems of long juvenility, nucellar embryogenesis and so on, genetic analysis in Citrus was difficult. Recently, however, linkage relationship of molecular genes has been reported by several workers, as the methods for molecular genetics develops. To use these genes as genetic markers and to develop the chromosome map for Citrus, it is essential to show which chromosome has them. The purpose of the present studies is to produce trisomic series using triploid citrus, and to identify the chromosome containing isozyme genes using trisomic series.
Both cross combinations 2X*3X and 3X*2X produced trisomic seedlings with chromosome number of 2n=19. But the frequency of trisomic seedlings obtained was very low. In the case of 2X*3X almost all seedlings obtained were dipliod with 18 chromosomes, and a few aneuploid seedlings were obtained. In the case of 3X*2X relatively a large number of aneuploid seedlings were obtained, but number of trisomic seedlings obtained was small. The undeveloped embryos within the imperfect seeds obtained from both crosses were cultured in vitro, but we failed to produce a alrge number of seedlings from these embryos. Only 10 seedlings obtained through the embryo culture were diploid. We improve the culture now.
In the present study, we obtained 18 trisomic seedlings. However, growth rate pf these seedlings were very low and some of them were dead Hence, we could not performed isozyme analysis using these seedlings. The morphology of chromosomes of trisomic seedlings was observed by several methods, but we could not identified the trisomic chromosome. Based on the present study, further research will be cont inued.
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