Stability Evaluation for Heat Tolerance in Lettuce: Implications and Recommendations.

Area of Science:

• Horticulture
• Plant Breeding
• Agronomy

Background:

• Lettuce (Lactuca sativa) is a cool-temperature crop highly susceptible to heat stress, a growing concern with climate change.
• Abiotic stresses, particularly high temperatures, significantly challenge lettuce cultivation and yield stability.
• Understanding genotype x environment interactions is crucial for developing heat-tolerant lettuce varieties.

Purpose of the Study:

• To investigate the relationship between genotype stability and heat tolerance in lettuce cultivars.
• To identify lettuce varieties exhibiting superior performance under heat stress conditions.
• To provide data for breeding programs focused on enhancing lettuce heat tolerance.

Main Methods:

• Field and greenhouse trials were conducted across different seasons (summer, fall, spring) and locations (field, glass, plastic greenhouse).
• Six lettuce genotypes (BRS Leila, BRS Mediterrânea, Elisa, Everglades, Simpson, Vanda) were evaluated for heat tolerance.
• Statistical analysis, including genotype x environment interaction (GEI), was performed to assess cultivar performance and stability.

Main Results:

• Significant effects of environment (E), genotype (G), and GEI were observed (p < 0.05).
• Cultivars BRS Leila, Elisa, and BRS Mediterrânea showed optimal performance (earliest anthesis) in milder temperature conditions.
• BRS Mediterrânea demonstrated the highest stability and adaptation to hot environments among the tested genotypes.

Conclusions:

• BRS Mediterrânea is a promising lettuce cultivar for cultivation in regions experiencing high temperatures.
• The findings highlight the importance of GEI in selecting heat-tolerant lettuce varieties.
• This research provides valuable information for developing and recommending lettuce cultivars adapted to future climate conditions.