Verification of the method of heat stress assessment for pea seed germination
Abstract
Climate warming has significantly increased temperatures across much of the world. The threat of heat
stress during the germination and seedling establishment stages of various agricultural crops is now more
prevalent than ever. Drought and heat stress during the growing season are limiting pea production. Many
growers are shifting the growing season of peas from summer to winter to escape the effects of stress.
However, this strategy has introduced new risks. It has moved the period of heat and drought stress to the
time of sowing and germination of the pea.
These changes require a new way of screening pea varieties for resistance to high temperatures and
maintaining germination potential. The temperature thresholds for pea plants and their responses are
inconsistent and not yet clearly identified. A simple approach to identifying HS-tolerant genotypes is to
screen the crop gene pool and landraces for HS tolerance in a specific environment. As a cool-season crop,
peas have a short vegetation period. To increase total area, cultivation, and production, there is a great need
for varieties that can be successfully grown in non-traditional areas. Their cultivation and expansion of area
will be challenged by the projected increase in temperature, both in the seasonal mean and in the occurrence
of extreme temperature events (Devi et al., 2023). Few studies have been published on the evaluation of the
effect of heat stress on the germination of pea seeds or on the screening for heat stress tolerance. The
experimental evaluation of the effect of elevated temperature on the germination and early seedling growth
of genotypes is a necessary tool in the modern breeding process.
The sensitivity of different crops to heat stress varies greatly. We need a method that is sensitive and
accurate for use in the screening process. For wheat, the critical temperature for germination is 35°C
(reduction of more than 75%) (Sharma et al., 2022), and for carrots – 37.5 (Bolton et al., 2019). Germination
and early growth of seedlings were significantly influenced by temperature.
The purpose of the experiment was to select the temperature and time regime to determine the semilethal dose (LD50) for a pea culture during a thermal test