Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/1/2013
Publication Date: 3/21/2014
Citation: Johnson, R.C., Evans, M. 2014. Comparative growth and development of hexaploid and tetraploid reed canarygrass. Crop Science. 54:1062–1069. Interpretive Summary: Reed canarygrass is an important forage species and potentially a biofuel, but is also an important invasive weed. It exists it two genetic types, a tetraploid and a hexaploid. However, the tetraploid type has been much more widely used and studied than the hexaploid. In this study we compared growth and development of 4 hexaploid and 6 tetraploid Reed canarygrass accessions at Central Ferry (CF), WA (relatively warm and dry) and Pullman (PU), WA (relatively cool and wet) over two years. The results showed strong differences in growth and development between the ploidy types. The hexaploids had generally later development and either longer or narrower leaves than tetraploids. Over the two year study tetraploids produced 28% more dry wt. than hexaploids at PU, but at CF, hexaploids produced 23% more than tetraploids. Overall the results were consistent with a higher potential production for hexaploids in the warmer, dryer location, which may be of increasing importance with climate change. Expanded research on hexaploid germplasm is needed but the National Plant Germplasm has only eight accessions of hexaploid Reed canarygrass available. Hexaploid Reed canarygrass may promote production in relatively warm, temperate climates but collection of additional diverse germplasm is needed to expand research opportunities.
Technical Abstract: Reed canarygrass (Phalaris arundinacea L.) is a globally distributed forage species, a potential biofuel, and an important invasive weed. At more northern latitudes in exists as a tetraploid and at equatorial to mid-latitudes as a hexaploid, especially in Mediterranean climates. Growth and development of ploidy types was compared on 6 hexaploid and 4 tetraploid accession at Pullman (PU) (cooler, wetter), and at Central Ferry (CF) (warmer, dryer), WA, by measuring 6 phenological, 7 morphological, and 7 production traits in 2010 and 201l. Minimum temperatures were as low as -24°C, but plant survival was near 100% for both ploidy types at both locations. There were frequent interactions with year and location but hexaploid development averaged 5-8 days later than the tetraploids. Even though ploidy groups had equal production capacity at CF in 2010 and at PU in 2011, overall, tetraploids at PU produced 28% more dry wt. than hexaploids, and hexaploids at CF 23% more than tetraploids (P<0.01). Using all traits, graphs of principal components 1 and 2, explaining 67% of the total variation, strongly distinguished the ploidy groups at PU both years, but the partitioning was somewhat more diffuse at CF. The results showed strong differences in growth and development between ploidy groups. Expanded use of hexaploids may promote production in relatively warm, temperate climates but collection of additional diverse germplasm is needed to expand research opportunities.