Screening for heat tolerance in Phaseolus spp. using multiple methods

Authors: TRAUB, JESSE - Michigan State University; Porch, Timothy - Tim; NAEEM, MUHAMMAD - University Of The Punjab; URREA, CARLOS - University Of Nebraska; AUSTIC, GREGG - Michigan State University; KELLY, JAMES - Michigan State University; LOESCHER, WAYNE - Michigan State University

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/7/2018
Publication Date: 8/18/2018
Citation: Traub, J., Porch, T.G., Naeem, M., Urrea, C., Austic, G., Kelly, J., Loescher, W. 2018. Screening for heat tolerance in Phaseolus spp. using multiple methods. Crop Science. https://doi.org/10.2135/cropsci2018.04.0275.
DOI: https://doi.org/10.2135/cropsci2018.04.0275

Interpretive Summary: Common bean is a nutritious crop grown around the world, and a staple food crop that provides high levels of protein and iron in the human diets of Central and South America and East Africa. Heat stress negatively impacts the seed yield of common bean and prevents their cultivation in certain areas. Furthermore, under field conditions, heat stress often coincides with and exacerbates the effects of drought stress. Breeding more heat tolerant common bean cultivars would stabilize seed yield and open new regions to field production. To support these efforts, this research examined a variety of methods for screening large numbers of bean germplasm exposed to heat stress at the vegetative growth stage as opposed to the reproductive stage, which would prolong the screening process. Tepary bean, a closely related species to common bean, was used as a heat stress tolerant check. Bean plants exposed to temperatures of 45 °C for two days showed measurable signs of heat stress, but tepary bean outperformed the common bean cultivars on all measures of stress tolerance. Gas exchange, chlorophyll fluorescence, and oxidative stress were only affected by this high temperature and not by temperatures below 45 °C. The measurements of heat stress also correlated well with visual signs of leaf tissue damage. Gradually raising the temperature was useful for screening large number of entries for heat tolerance, but this heat tolerance was only partially related to drought tolerance observed in the field. Plant breeders can utilize some of the methods described here to supplement field data and to further characterize the stress tolerance of bean lines.

Technical Abstract: Common bean (Phaseolus vulgaris L.) is a nutritious crop grown around the world, and a staple food crop that provides high levels of protein and iron in the human diets of Central and South America and East Africa. Heat stress negatively impacts the seed yield of common bean and prevents their cultivation in certain areas. Furthermore, under field conditions, heat stress often coincides with and exacerbates the effects of drought stress. Breeding more heat tolerant common bean cultivars would stabilize seed yield and open new regions to field production. To support these efforts, this research examined a variety of methods for screening large numbers of bean germplasm exposed to heat stress at the vegetative growth stage as opposed to the reproductive stage, which would prolong the screening process. Tepary bean (Phaseolus acutifolius A. Gray), a closely related species to common bean, was used as a heat stress tolerant check. Bean plants exposed to temperatures of 45 °C for two days showed measurable signs of heat stress, but tepary bean outperformed the common bean cultivars on all measures of stress tolerance. Gas exchange, chlorophyll fluorescence, and oxidative stress were only affected by this high temperature and not by temperatures below 45 °C. The measurements of heat stress also correlated well with visual signs of leaf tissue damage. Gradually raising the temperature was useful for screening large number of entries for heat tolerance, but this heat tolerance was only partially related to drought tolerance observed in the field. Plant breeders can utilize some of the methods described here to supplement field data and to further characterize the stress tolerance of bean lines.