Variety traits

Heat tolerance in pepper

Capsicum annuum L.

The ability of pepper to maintain productivity and physiological functions when exposed to temperatures above 32–33 °C. The main indicators are pollen viability, cell membrane thermostability, and the ability to set fruit under stress.

In the reference 8 varieties crop Bell pepper, where this is mentioned in the description.

Heat tolerance in pepper is evaluated through reproductive and physiological parameters. The key criterion is pollen viability, measured at temperatures from 10 °C to 45 °C, as well as fruit set. Important assessment tools include the Heat Susceptibility Index (HSI), which characterizes yield reduction, and the Cell Membrane Thermostability (CMT) test, determined by the electrical conductivity of leaf tissues.

When exposed to temperatures above 35–40 °C, heat-tolerant pepper forms maintain photosynthetic intensity and transpiration efficiency, which is reflected in the difference between canopy and air temperatures. Sensitive varieties demonstrate mass flower drop due to pollen sterility, rapid stomatal closure, and a yield reduction of more than 50 percent when the threshold of 32–33 °C is exceeded.

The lack of heat tolerance during the pepper flowering period leads to the formation of 'barren flowers' and also affects fruit marketability, such as weight, shape, and size. Researchers use the Cumulative Temperature Response Index (CTRI) for the integral classification of genotypes based on their level of resistance to heat stress.

General information about the subject — on the page Heat tolerance.

Sources8

Varieties of Bell pepper mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.