Response of lentil to high temperature under variable water supply and carbon dioxide enrichment

Abstract

Lentil (Lens culinaris Medik.) production in arable, Mediterranean-type climates is limited by heat waves and unreliable rainfall. Under climate change scenarios, increased atmospheric carbon dioxide (CO2) concentration will increase plant growth; however, the net effect of increasing occurrence and intensity of heat waves and drought is unclear. This study tested the response of combined acute high temperature (>32°C) at the early pod-filling stage and (i) crop-available soil water, and (ii) elevated CO2 on three lentil genotypes in two experiments. The three lentil genotypes selected were commercial cultivar PBA Bolt and two landraces sourced from the Australian Grains Genebank, AGG 71457 and AGG 73838. High soil-water availability (0.42 Mg m–3) throughout the growing season increased yield by 28% compared with low soil-water availability (0.35 Mg m–3). Across contrasting water treatments, there was no difference in patterns of crop response to high temperature during the early pod-filling phase (5 days at 42°C daytime, 25°C night), where yields were reduced by 45%. A significant interaction between high temperature response and genotype was observed, where reduction in grain number was higher for AGG 73838 (0.20% per degree-hour >32°C) than for AGG 71457 (0.07% per degree-hour >32°C) or PBA Bolt (0.10% per degree-hour >32°C). For heat and CO2 effects, there was no significant interaction between high temperature (3 days at 38°C daytime, ambient night temperature) and CO2 treatment on yield components. There was, however, an overall trend of increased biomass, grain number and yield due to elevated CO2. Although non-limiting soil water did not reduce the impact of high temperature in this study, the range in response across genotypes to high temperature supports opportunity for increased adaptation of lentil toward increasing yield stability under effects of climate change.

Impact of heat stress during seed filling on seed quality and seed yield in lentil (Lens culinarisMedikus) genotypes

“…Heat stress reduced the seed number per plant due to reduced pod set and fewer filled pods, which agrees with previous observations on chickpea, mungbean and lentil . Heat stress also reduced seed size, resulting in much lower seed weights per plant and individual seed weights, which appears to be related to a reduction in the seed filling rate and duration.…”

“…Temperatures above 32/20 °C (max./min.) at the time of flowering and pod filling in lentil can drastically reduce seed yield and quality . In 2009, across southeastern Australia, a heat wave (35 °C for 6 days) reduced lentil yields by 70% …”

Breeding, genetics, and genomics for tolerance against terminal heat in lentil: Current status and future directions

“…It is mainly cultivated in Indian subcontinent, West‐Asia, and Australia where it faces heat stress. Heat stress is a period of hot temperature that causes irreversible damage during growth and development of crop plants (Delahunty, Nuttall, Nicolas, & Brand, 2018). In major growing areas, lentil crop is exposed to temperature >35°C at flowering and pod filling stages during maturity (Delahunty, Nuttall, Nicolas, & Brand, 2015).…”

“…However, during the past years, continuous efforts have been made to study the heat stress tolerance in lentil. These studies identified the heat tolerant genotypes and the associated morpho‐physio‐biochemical traits, characterized the heat tolerance at molecular level, and deciphered the genetics and pathways underlying the heat stress tolerance in lentil (Kumar et al, 2016; Singh et al, 2016; Kumar, Basu, et al, 2018; Singh, Singh, Singh, & Pal, 2017; Delahunty et al, 2018; Singh et al, 2019). Also, knowledge of heat stress in lentil is enriching day by day and is becoming available in the public domain.…”

Effect of heat wave on N2 fixation and N remobilisation of lentil (Lens culinaris MEDIK) grown under free air CO2 enrichment in a mediterranean‐type environment

“…Elevated [CO 2 ], in combination with high temperature, increased biomass accumulation in legume crops (Wang et al ). Recent studies (Bourgault et al ; Delahunty et al ) reported that e[CO 2 ] could not fully protect against reduced grain yield from heat waves, but at least moderated the negative effects. This might be associated with higher photosynthetic CO 2 assimilation under e[CO 2 ] following heat events (Shanmugam et al ), resulting in higher grain yield.…”