Phenotyping a diverse collection of forage sorghum genotypes for chilling tolerance

Authors: PODDER, SWARUP - Virginia Polytechnic Institution & State University; SAMARAPPULI, DULAN - North Dakota State University; Anderson, James; BERTI, MARISOL - North Dakota State University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2020
Publication Date: 7/25/2020
Citation: Podder, S., Samarappuli, D., Anderson, J.V., Berti, M.T. 2020. Phenotyping a diverse collection of forage sorghum genotypes for chilling tolerance. Agronomy. 10(8):1074. https://doi.org/10.3390/agronomy10081074.
DOI: https://doi.org/10.3390/agronomy10081074

Interpretive Summary: Forage sorghum is a warm-season biomass crop that is generally tolerant to abiotic stresses and can grow well on marginal land. However, a main limitation of forage sorghum production in the North Central Region (NCR) of the U.S. is its lack of tolerance to temperatures below 15 C, especially early in the growing season. Thus, increasing chilling tolerance could increase its utilization in the NCR of the U.S. as a biomass feedstock. In this study, seventy-two genotypes of forage sorghum were ranked for high to low vigor index (germination rate) under controlled conditions at 24, 12, and 10 C, with field experiments conducted on a subset of 12 genotypes at two locations in North Dakota using early (10 May) and late (27 May) season planting dates. Under field conditions, seedling mortality and biomass yield were affected by the seeding date and, as expected, field germination rates were greater for the late-seeding compared with the early-seeding date. However, some forage sorghum genotypes in this study produced greater biomass yield when seeded earlier than normal, which could allow for breeding these chilling tolerance traits into forage sorghum.

Technical Abstract: Forage sorghum (FS) [Sorghum bicolor (L.) Moench] is a warm-season biomass crop with the potential to become a bioenergy feedstock. The objective of this study was to screen potential FS genotypes for increased chilling tolerance and biomass productivity. Seventy-two genotypes of FS were first ranked for high to low vigor index under controlled conditions at 24, 12, and 10 C. Field experiments were also conducted on a subset of 12 genotypes in Fargo and Hickson, ND, USA in 2017 and 2018, using two different seeding dates: early (10 May) and late (27 May). Field emergence index values were greater for the late-seeding compared with the early-seeding date. Under field conditions, seedling mortality and biomass yield were affected by the seeding date and biomass yield correlated with emergence index and normalized vegetative index. Chemical composition of FS biomass was not affected by the seeding dates. The results of this study indicate that some FS genotypes carry genetic traits for increased chilling tolerance and produce greater biomass yield when seeded earlier than normal, which could allow for breeding chilling tolerance into FS.