Dr. Jack Juvik
Professor of Plant Genetics
Ph.D. in Genetics, University of California at Davis, 1980.
1201 W. Gregory Drive
Urbana, IL 61801
Miscanthus x giganteus is a sterile triploid (2N=57) hybrid generated from the cross of M. sinensis with M. sacchariflorus. Generation of new hybrids from this cross can be difficult to achieve and has restricted the development of useful genetic diversity for breeding improvement. A single geneotype accounts for the majority of all the acreage currently in commercial production. To date there have been no efforts to develop Miscanthus genotypes adapted to US environments. We have initiated a program designed to develop improved genotypes of M. x giganteus through two primary approaches: Conventional hybridization of M. sinensis with M. sacchariflorus to generate new germplasm adapted to growing conditions in Illinois; and in cooperation with Dr. Jack Widholm development of a Miscanthus transformation system to introduce benificial genes into existing genotypes. Following development of a transformation system we plan to utilize directed mutagenesis to create new genetic diversity, transform existing germplasm with genes that can potentially increase Miscanthus productiviy or reduce production costs and silence flower induction genes prolonging vegetative growth while enhancing plant biomass production.
Completed and Ongoing Research Activities:
1. Acquisition of Miscanthus and Saccharum germplasm. We have acquired a new M. x giganteus accessions, which (Carl Brunell nursery) has a different DNA content than the UIUC M. x giganteus (8.2 to 7.0 pg/nuclei, respectively) and two additional M. sacchariflorus lines.
2. Re-synthesis of Miscanthus x giganteus. While sterility of M. x giganteus accessions limits their invasiveness, it places a serious constraint on breeding for improved cultivars and on stand establishment requiring vegetative propagation of rhizome cuttings. We have conducted over the last year several hundred greenhouse hybridizations between the parental species of M. x giganteus, M. sinensis, and M. sacchariflorus without successfully generating any viable seed from these crosses.
3. Sexual hybridization of other Miscanthus species. M. sinensis is itself a prime target species for feedstock production based on its performance in European trials, high degree of phenotypic and genetic variation, and its capacity to generate viable seed. Using 16 M. sinensis accessions we have initiated crosses among paired parent plants that show distinct morphological phenotypes and biomass yields. Since these accessions are highly heterozygous, progeny from these crosses will segregate and be amenable to linkage mapping using DNA markers. We have harvested seed from three of these crosses. Three segregating populations of M. sinensis (approximately 100-150 plants/population) were planted in the greenhouse and transplanted to the Soyface field plots for phenotypic evaluation and DNA genotyping. These populations will serve as platforms for the association of phenotypic traits with genomic tools to develop genetic linkage and physical maps of the genome, QTL mapping, and sequences for marker-assisted breeding.
4. Chromosomal doubling of M. x giganteus. Mr. Joseph Crawford (undergraduate student on a JBT Undergraduate Research Scholarship) and Dr. Cheon Yu (visiting Professor from Korea) have been attempting to double the chromosome number of M. x giganteus to convert it from a triploid to a hexaploid plant via colchicine treatments of explant tissue or callus cultures. Chromosome doubling in other plant species has been shown to increase vegetative growth and biomass. Generation of hexaploid M. x giganteus plants by chromosome doubling could also restore plant fertility to promote conventional breeding. Treatments with colchicine and oryzalin on M. x giganteus callus cultures were observed to double callus DNA content as measured by flow cytometry in 52% of the treated colonies. We have to date regenerated 8-10 putative hexaploid plants from callus colonies that show doubled DNA content. These will be moved to the greenhouse for evaluation of biomass productivity and potential fertility.
5. Generation and evaluation of somoclonal variants of Miscanthis x giganteus. In collaboration with Dr. Widholm we have evaluated approximately 120 tissue culture regenerated plants that were planted at the Soyface plots over the past two years. Evaluation last fall and this summer has uncovered no clear phenotypic evidence of somoclonal variation.
6. DNA content of Miscanthus species. In cooperation with Dr. Lane Rayburn, Joseph Crawford has evaluated the leaf stomata size and DNA content of several Miscanthus accessions by flow cytometry. The results are presented in the following table.