Seed source may determine field-specific germination and emergence: the source by planting environment interaction

Authors: Espeland, Erin; PERKINS, LORA - South Dakota State University; HORNING, MATT - Forest Service (FS); Johnson, Richard

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2015
Publication Date: 8/6/2015
Publication URL: http://handle.nal.usda.gov/10113/61791
Citation: Espeland, E.K., Perkins, L.B., Horning, M.E., Johnson, R.C. 2015. Seed source may determine field-specific germination and emergence: the source by planting environment interaction. Crop Science. 56(1):249-258. doi:10.2135/cropsci2015.05.0318.

Interpretive Summary: We know that maternal effects can be important for seed performance: well-watered, well-fertilized plants often produce larger seeds with high germination. Other, adaptive, maternal effects such as drought- and herbivory- tolerance have been recorded for plants, where maternal plants that experience drought or herbivory pass tolerance to these stressors on to their progeny. Therefore, seed production environment may affect seed performance in multiple ways. We used Lodorm green needlegrass, Pryor slender wheatgrass, and P-7 bluebunch wheatgrass produced at multiple farms to test how farm environment affected germination, emergence, and response to seed storage in several test environments. P-7 performance did not differ among farm sources. Pryor slender wheatgrass was very responsive to farm environment and seed storage environment, but lab and field test environments did not exhibit the same results. For example, room-temperature stored seeds of Pryor had the best emergence in the field and the worst germination in the lab. Lodorm green needlegrass showed a response to the interaction of farm source and planting environment in the field but not in laboratory environments, which demonstrates that laboratory assays may not provide adequate information regarding differential performance of seeds from multiple farms. In some field environments, one farm source could have as much as double the emergence as other sources, therefore understanding the contribution of farm environment to field performance can enhance our management of native plant seed production and restoration applications.

Technical Abstract: Farm environmental characteristics and management practices can result in within-cultivar differences in seed quality. Transgenerational plasticity (effects of the farm environment on offspring, or TGP) can be important in germination and emergence dynamics. We chose two commonly-used cultivars (Lodorm and Pryor) and one prevariety registered germplasm (P-7) of three perennial bunchgrass species (green needlegrass, slender wheatgrass, and bluebunch wheatgrass) to determine if seeds exhibit TGP and if the effect of that plasticity changes depending on planting environment (i.e. context-dependent TGP). We conducted laboratory germination experiments in 2013 in four temperature regimes and placed seeds in four field environments to examine emergence. We stored seeds in four different environments for ten months and performed similar laboratory and field experiments in 2014 to test if seed storage environment mitigated TGP. Context-dependent TGP determined emergence for the two cultivars in both years, however only Pryor exhibited context-dependent TGP for germination in the lab in 2013. Farm sources with low performance in the field and the lab were less likely to exhibit context-dependent TGP. Some transplant environments did not show differences among farm sources, but in some transplant fields, the effect of farm increased emergence as much as 24%. Laboratory experiments on germination did not provide an assay for context-dependent TGP found in the field, and the effect of seed storage (which was only significant for Pryor) was opposite for lab and field studies, with room-temperature stored seeds having best emergence in the field and the worst germination in the lab. When seed is costly and increasing emergence by 10 to 24% is important, such as in restoration applications, understanding the contribution of farm and storage environments to site-specific field performance will contribute significantly to the success of these enterprises.