|SOSA, SERGIO - Rutgers University|
|HOFFMAN, LINDSEY - Rutgers University|
|MAYTON, HILARY - Cornell University - New York|
|ERNST, CALVIN - Ernst Conservation Seeds|
|BOE, ARVID - South Dakota State University|
|BONOS, STACY - Rutgers University|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/29/2019
Publication Date: 3/3/2017
Citation: Casler, M.D., Sosa, S., Hoffman, L., Mayton, H., Ernst, C., Adler, P.R., Boe, A., Bonos, S.A. 2017. Biomass yield of switchgrass cultivars under high-input vs. low-input conditions. Crop Science. 57:821-832.
Interpretive Summary: Switchgrass is undergoing development as a biomass crop to support conversion of cellulosic biomass to energy. To avoid competition of biomass with food or feed crops, most commercialization proposals suggest that switchgrass should be grown exclusively on marginal lands that are not fit for food or feed production. Currently, nearly all breeding and selection to create new varieties of switchgrass is conducted on prime farmland, using nitrogen fertilizer, pesticides, and numerous other inputs. The purpose of this study was to determine if this is the correct approach or if breeding new varieties under high-input conditions is creating varieties that will not perform well under low-input conditions. The study showed that there were significant changes in rank performance among switchgrass varieties, depending on soil quality (depth and fertility of the top soil) and the use or absence of nitrogen fertilizer. The study concluded that breeders should put at least some of their efforts and resources toward creating one or more selection sites that mimic a low-input and marginal type of land base for use in breeding and selection of new varieties for that type of land. The consequences of failing to do this would not be felt for many years, perhaps decades, but would nevertheless be a proliferation of new varieties that are poorly adapted to the predominant type of environment set aside for switchgrass biomass production.
Technical Abstract: Switchgrass is undergoing development as a biomass crop to support conversion of cellulosic biomass to energy. To avoid competition of biomass with food or feed crops, most commercialization proposals suggest that switchgrass should be grown exclusively on marginal lands that are not fit for food or feed production. The objective of this study was to investigate the potential for cultivar × environment interactions that would impact the methods and approaches for breeding and evaluating switchgrass cultivars for high-input vs. low-input types of environments. Biomass yield was measured on 14 cultivars that were present in 14 replicated field experiments representing seven regions, ranging from 75 to 100oW longitude and spanning USDA Hardiness Zones 4 through 7. Region was the most important environmental factor interacting with cultivars, supporting the idea that the North Central and Northeastern USA should have independent breeding programs designed to develop cultivars specifically adapted to those regions. Cultivars interacted with one soil quality factor, depth and fertility of the A horizon in New Jersey, and showed mild interactions with rate of nitrogen fertilizer at several locations. Cultivar rank correlation coefficients between the two rates of nitrogen fertilization (100 vs. 0 kg N ha-1) ranged from 0.27 to 0.88, suggesting a possible benefit to breeding and selection without applied nitrogen fertilizer.