Seed-to-seed early-season cold resiliency in sorghum

Authors: Emendack, Yves; Sanchez, Jacobo; Hayes, Chad; Nesbitt, Matthew; LAZA, HAYDEE - Texas Tech University; BURKE, JOHN - Retired ARS Employee

Submitted to: Nature Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/26/2021
Publication Date: 4/8/2021
Citation: Emendack, Y., Sanchez, J., Hayes, C.M., Nesbitt, M.E., Laza, H., Burke, J.J. 2021. Seed-to-seed early-season cold resiliency in sorghum. Nature Scientific Reports. 11. Article 7801. https://doi.org/10.1038/s41598-021-87450-1.
DOI: https://doi.org/10.1038/s41598-021-87450-1

Interpretive Summary: Low temperatures often affect plant growth and crop productivity which causes significant crop loses. For sorghum, early season low temperatures can result in poor seedling establishment, low growth rates, and decreased pollen viability leading to low yields. Improved cold tolerance could increase the range of environments where sorghum is produced as well as provide alternative planting options, such as early planting, to add flexibility to the production system by allowing earlier planting of winter crops. This study examined the response of different sorghum lines and hybrids with different background for cold tolerance, with the goal of identifying new sources of cold tolerance that could be crossed with high yielding commercial lines to improve their cold tolerance. The responses of the lines grown at three planting dates (Early; April 1st, Mid; May 1st, and Standard; June 1st) in West Texas were looked at from seedling to maturity (seed-to-seed). The lines as well as the sources of cold tolerance showed variability for the evaluated traits within and across planting dates during seedling to the early developmental stages, and at maturity. Grain yield was significantly reduced when seeds were planted early or mid compared to the standard planting date. Lines with Ethiopian background for cold tolerance experienced the lowest yield loses compared to the Chinese sources when planted earlier.

Technical Abstract: Early planted sorghum usually experienced cooler day/night temperatures, which may result in delayed growth, floral initiation, and infertile pollen, limiting productivity in high altitudes and temperate regions. Genetic variability for cold tolerance in sorghum has been evaluated by characterizing germination, emergence, vigor, and seedling growth under sub-optimal temperatures. However, the compounded effect of early season cold on plant growth and development and subsequent variability in potential grain yield loses has not been evaluated. The agro-morphological and physiological responses of sorghum grown under early, mid, and standard planting dates in West Texas were characterized from seed-to-seed using diverse lines and hybrids with different cold tolerant sources previously selected at the seedling stage. These were evaluated in comparison with a standard commercial and other cold tolerant hybrids, inbreds and susceptible checks. Variabilities in assessed parameters at seedling, early vegetative, and maturity stages were observed across planting dates for genotypes and sources of cold tolerance. Panicle initiation was delayed and panicle size reduced leading to decreases in grain yields under early and mid-planting dates. Coupled with final germination percent, panicle width and area were significant unique predictors of yield only under early and mid-planting dates. Significant variability in performance was observed not only between cold tolerant and susceptible lines but noticeably between sources of cold tolerance, with the Ethiopian highland sources having lesser yield penalties than their Chinese counterparts. Thus, screening for cold tolerance should not be limited to early seedling characterization but should also consider agronomic traits that may affect yield penalties depending on the sources of tolerance.