|YOON, SANGWOONG - University Of California|
|BLUMWALD, EDUARDO - University Of California|
|MITCHELL, ROBERT - University Of Nebraska|
|GAUTAM, SARATH - University Of Nebraska|
|PALMER, NATHAN - University Of Nebraska|
|EDME, SERGE - University Of Nebraska|
|Hernlem, Bradley - Brad|
|AUCAR, SHEYLA - University Of California|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/5/2016
Publication Date: 8/5/2016
Citation: Yoon, S., Blumwald, E., Mitchell, R., Gautam, S., Palmer, N., Edme, S., Hernlem, B.J., Aucar, S., Tobias, C.M. 2016. Generation of Neo Octaploid Switchgrass. Meeting Abstract. 5th Pan-American Congress on Plants and BioEnergy, Santa Fe, NM, August 4-7, 2016.
Interpretive Summary: To study the physiological, biochemical, and molecular effects of whole genome duplication in plants, natural and induced polyploids have been used extensively and induced polyploidy has been an established breeding method for over 50 years. A large number of physiological and biochemical processes are impacted in polyploids including rates of photosynthesis, enzyme activity, and accumulation of secondary metabolites. These changes can be desirable in some cases and have led to improvements in forage quality, seedlessness, and other traits. To further study genome duplication in switchgrass, a population of polyploids was produced that will be compared with natural polyploids.
Technical Abstract: Switchgrass (Panicum virgatum L.) exists as multiple cytotypes with octaploid and tetraploid populations occupying distinct, overlapping ranges. These cytotypes tend to show differences in adaptation, yield potential, and other characters, but the specific result of whole genome duplication is not clear and 8x and 4x switchgrass populations are reproductively isolated with limited genetic exchange. To create new opportunities for population improvement and to study the effects of whole genome duplication on switchgrass, seedling treatment of the tetraploid cultivar 'Liberty' with microtubule inhibitors was used to generate an octaploid population. Resulting octaploids, tetraploids, and cytochimeras were resolved by intercrossing octaploid sectors to produce a population of 19 octaploid families. Fertility of octaploid sectors was significantly reduced relative to tetraploid sectors and caryopsis size significantly increased. Cell size was significantly increased which resulted in quantitative changes to leaf anatomy. During seedling and early vegetative growth stages, no differences in vigor or tillering ability were seen. This technique resulted in efficient genome doubling and was simple to perform. However, aneuploids were also identified with both larger and smaller than expected genome sizes.