Green yield as a potential predictor of cured burley tobacco yield in a Phytophthora nicotianae-infested field over four seasons.

Authors: Pfeufer, Emily; BARLOW, WILLIAM - University Of Kentucky; PEARCE, ROBERT - University Of Kentucky

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2022
Publication Date: 3/21/2023
Citation: Pfeufer, E., Barlow, W.B., Pearce, R. 2023. Green yield as a potential predictor of cured burley tobacco yield in a Phytophthora nicotianae-infested field over four seasons. Plant Health Progress. https://doi.org/10.1094/PHP-09-22-0085-RS.
DOI: https://doi.org/10.1094/PHP-09-22-0085-RS

Interpretive Summary: Phytophthora-induced crop diseases often result in total yield loss. To prevent these losses, plant scientists have focused on incorporating Phytophthora disease resistance into crops and comparing fungicides for efficacy. A common way these are measured is by counting plants that survive to season end, however, these do not always relate to larger yields. This research evaluates a method to predict cured yields for three groups of tobacco varieties with low, moderate, and high resistance to black shank, the most significant soilborne disease of tobacco. Results indicated that a green yield estimate more closely estimated cured yield than plant survival did. This information contributes to the broader literature on how to measure the effects of Phytophthora-induced diseases, and may be used by plant breeders and plant pathologists in planning their experiments. Extension educators, commercial growers, and industry also benefit from this information by being better able to educate growers, plan harvest processes, and manage inventory, respectively.

Technical Abstract: Phytophthora-induced plant diseases are most effectively managed using an integrated strategy that includes host resistance, best cultural practices, and fungicide applications. Black shank, caused by Phytophthora nicotianae, is the most significant soilborne disease affecting tobacco, and extensive breeding for resistance has resulted in an array of varieties with a spectrum of black shank resistance. Estimates of plant survival are the traditional output variable of tobacco black shank trials, however, survival may not be the most accurate indicator of yield for varieties with robust resistance. Through the presented analyses, at-harvest green yield estimates are shown to be more closely associated with cured tobacco yields than survival counts, irrespective of black shank resistance status. However, green yield may only be considered a standalone yield predictor for low resistance varieties, with other factors likely contributing to cured yield of moderate and high resistance varieties. This prevents development of a variety nonspecific cured yield model, which would be useful not only for plant pathologists, but also commercial growers in planning labor activities and the industry at-large in managing cured tobacco inventory.