Development of an in vitro Microtuberization and Temporary Immersion Bioreactor System to Evaluate Heat Stress Tolerance in Potatoes (Solanum tuberosum L.)

Abstract

High temperature (heat) stress reduces tuber yield and quality of potatoes. Screening potatoes for heat tolerance is increasingly important, considering the climate change scenario and expansion of potatoes to countries where heat stress is an issue. In vitro screening for tolerance to abiotic stresses offers several advantages, including quick evaluation of numerous genotypes (clones) in reduced space, controlled environmental conditions (temperature and photoperiod), and free from confounding variables inherent to greenhouse and field conditions. In this study, we explored the feasibility of using a temporary immersion bioreactor system for heat tolerance screening of potatoes. We determined the best hormone-free microtuberizing media for this system (MSG with 8% sucrose) to enhance microtuber number and size. Comparisons of microtubers produced at 30°C as heat treatment, with 16°C as normal condition, allowed to identify heat tolerant and susceptible potato clones. The use of bioreactors allowed distinguishing well-formed (non-deformed) from deformed microtubers. Heat stress increased the total biomass of plant tissues in all the clones. However, the effect of heat stress on microtuber number and weight varied among the clones. Incubation at 30°C decreased the weight and number of non-deformed microtubers in all the clones except for Reveille Russet in which the weight of non-deformed microtubers was significantly increased and the count of non-deformed microtubers was not affected. The potato variety Reveille Russet, which was selected under high-temperature field conditions in Texas, had many non-deformed microtubers per explant and the highest microtuber weight among four clones evaluated under heat stress. We described a faster and reliable in vitro microtuberization system for abiotic stress tolerance screening, identified Reveille Russet as a promising heat-tolerant potato variety, and confirmed Russet Burbank and Atlantic as susceptible heat-tolerant checks.

Multivariate Analysis Compares and Evaluates Heat Tolerance of Potato Germplasm

“…Previous studies have shown that microtubers grown in vitro are essentially identical to tubers grown in the wild in terms of tissue structure, growth and development, and genetic stability [ 22 ]. In vitro screening for tolerance to heat stress are faster and reliable [ 23 ]. Khan et al [ 13 ] suggested that inducing in vitro potatoes under high temperatures could be used as a method for screening heat-resistant cultivars.…”

Assessing heat tolerance in potatoes: Responses to stressful Texas field locations and controlled contrasting greenhouse conditions

“…Reveille Russet exhibits unique traits such as long dormancy and late emergence. Its late emergence may mask its potential heat tolerance ( Gautam et al., 2021 ). Early exposure to high temperatures and premature tuber harvesting can reduce tuber marketable yield, specific gravity, dry matter, and dormancy.…”

“…Early exposure to high temperatures and premature tuber harvesting can reduce tuber marketable yield, specific gravity, dry matter, and dormancy. Despite successful evaluation in lab conditions ( Gautam et al., 2021 ), assessing Reveille Russet for heat tolerance in the field and greenhouse remains challenging due to its shorter growth period. In greenhouse trials, Sierra Gold and Yukon Gold were identified as high-yielding clones using a multi-trait stability index, with shorter maturation periods than other russet varieties.…”

Raman spectroscopy detects chemical differences between potato tubers produced under normal and heat stress growing conditions

“…It is challenging to bring new land into the production system and intensify production. An effective way of alleviating the detrimental effects of heat stress, whether short or long-term, is to develop heattolerant plant cultivars (Bonnel, 2008;Demirel et al, 2017;Busse et al, 2018;Gautam et al, 2021). Developing a tolerant cultivar begins with identifying promising germplasm that can provide quality yield so that its introgression into the potato gene pool is possible (Bashir et al, 2022).…”