Phenological and physiological responses of hybrid rice under different high-temperature at seedling stage

Abstract

Background The projected increase in global temperature is expected to negatively impact food production in many regions. Rice exposure to heat stress can limit plant growth in different stages, especially at the seedling stage. In this experiment, two Indica parental lines N22 (heat tolerant) and BIM (heat sensitive) along with their F2 hybrid were elucidated under different high temperatures (28 °C, 35 °C, and 42 °C) at the seedling stage. Results The results indicated that the F2 hybrid inherited the heat tolerance rate from the male heat-tolerant N22 parent. Based on phenological and physiological attributes, the F2 hybrid exhibited excessive-performance as compared to its BIM parent under different high-temperature conditions. Specifically, absorbing the ample available water through the long-rooted system enabled rice seedlings to carry out high transpirational cooling. Furthermore, there was a strong relationship (r = 0.89, p < 0.01) between root length and transpiration rate under 42 °C. The temperature 35–42 °C caused a significant reduction in seedlings’ growth, chlorophyll content, and survival rate (18–20%), while the relative heat injury percentage and leaf temperature increased in heat-sensitive BIM parent as compared to F2 hybrid. Conclusion This study suggests that the breeding of heat-tolerant hybrid rice plays an important role in the production of a resilient rice plant through heat-tolerant seedlings at the initial vegetative growth stage.

Auxin Application at the Flowering Stage of Rice Alleviates the Negative Impact of Heat Stress on Spikelet Fertility and Yield Attributes

“…Heat stress has a significant impact on rice growth and physiological parameters. However, the plant tolerance rate and temperature rate perform a key role in stomatal conductance, depending on the rice genotype [15]. The increment in environmental temperature causes high leaf temperature which leads to heat injury in rice [48], but plants still tend to utilize ample water in the process of transpirational cooling of the canopy.…”

“…Furthermore, rice exposed to temperatures above 38 • C for an hour did not have a significant effect on the spikelet fertility rate [12,13]; however, continuous temperatures exceeding 33.7 • C can lead to spikelet sterility [14]. In rice, high temperature prompts a significant reduction in photosynthesis, stomatal conductance, and causes high leaf temperature [11,15]. The impact of heat stress can be observed in a decrease in biomass due to limited photosynthesis, primarily caused by reduced stomatal conductance [16].…”

Agronomic and Physiological Indices for Reproductive Stage Heat Stress Tolerance in Green Super Rice

“…According to projections, it is expected that environmental fluctuations, especially high temperature stress, may cause a 41% yield decline by end of this century [17,18]. High temperature stress destructively impacts the rice metabolism in all growth phases [19][20][21].…”

“…Rice seedlings are very sensitive to the critical high temperature of 35 • C [22]. Further elevation beyond the critical high temperature can be destructive and may lead to plant death at respective growth stages [18,23]. The frequent occurrence of extreme climatic events, such as high temperature, leads to adverse impacts on rice growth and development.…”

Effect of Heat Stress on Rice and Its Management

“…HS also has detrimental effects on the plant root system that provides water uptake, nutrient uptake and supports other parts of the plant, leading to disruption of root growth and development, as well as decrease in shoot and root fresh, and dry weight" [6]. "The chlorophyll content is the primary key component for photosynthesis" [7]. It is drastically affected by high temperature at the vegetative stage.…”