This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Somaclonal Variation in Soybeans
Barwale, Usha Badrinarayan
Doctoral Committee Chair(s)
Widholm, Jack M.
Department of Study
Degree Granting Institution
University of Illinois at Urbana-Champaign
Agriculture, Plant Culture
Tissue culture induced variation in regenerated plant progeny, up to R$\sb4$ generation (four cycles of self-pollination away from the regenerated plants) was studied. Several mutants/variants were seen, majority of them derived from the organogenic culture system. Variants such as wrinkled leaf phenotype (with a simple recessive Mendelian inheritance) and sterility (single recessive gene trait) were seen in three or more generations of the same family. Wrinkled leaf phenotype was associated with partial sterility and may be unstable since some plants showed sectors of the normal branches on a wrinkled plant and some had wrinkled branch sectors on normal plant.
Partial sterility, multiple branching and dwarf growth habit were observed as stable traits seen in more than two generations but the segregation ratios do not fit a simple model. Several other traits like chlorophyll deficiency, abnormal leaflet morphology, abnormal leaflet number and twin seeds were seen in one generation only.
Somaclones of resistant and susceptible genotypes to brown stem rot were screened using an in vitro system for changes in tolerance. The system allowed for differentiation between resistant and susceptible genotypes when calli were treated with culture filtrate at different dilutions. Some somaclones did show greater tolerance and others showed greater susceptibility than the control. Greenhouse screening of these selected somaclones would confirm these results.
Oil and protein content of somaclones in the R$\sb4$ generation were also determined. Increases and decreases up to 9% were seen. Next generation needs to be tested to see if the changes are stable and heritable.
Chromosomal abnormalities such as mixaploidy were associated with wrinkled leaf phenotype, partial sterility and multiple branching when chromosome counts were done on root tips. Attempts to establish involvement of transposable elements in inducing somaclonal variation produced inconclusive results.
Somaclonal variation for both qualitative and quantitative trait was noted. Chromosomal abnormalities in part induced some of this variation.