Does post‐anthesis heat stress affect plant phenology, physiology, grain yield and protein content of durum wheat in a semi‐arid Mediterranean environment?

Abstract

Increasing air temperature due to changing climate is projected to decrease the length of the growing season, hasten vegetative development and maturation, and ultimately affect yield of many C3 crops. Previous multilocation trials highlighted strong relationships between thermal trends in the interval “beginning of flowering‐end of grain filling” and grain yield, and protein content in durum wheat (Triticum turgidum subsp. durum (Desf.) Husn.). With the aim to confirm these relationships, nine durum wheat genotypes, including old (Capeiti 8, Senatore Cappelli and Trinakria) and modern (Amedeo, Arcangelo, Mongibello, Simeto, and Svevo) varieties and a Sicilian landrace (Russello) were grown at three different sites representing a climate gradient in Sicily, Italy. Moreover, the effect of post‐anthesis heat stress on these durum wheats was further investigated in two contrasting environments: open‐field (control—C) and greenhouse heat stress (HS). HS shortened the interval “beginning‐end of flowering” of 1.5 days across genotypes, and the “end of flowering‐beginning of grain filling” and maturation of 4.9 days, with a range of 1 day in Arcangelo to 11 days in Cappelli. Advances in main phenophases significantly decreased kernel weight (KW) and grain yield (GY), whereas grain protein content (PC) increased. As expected, a negative relationship was observed between GY and PC, while positive relationships were found for GY and grain‐filling duration (GFD), and GY and KW. Genotypes responded differently to heat stress, as evidenced by the net photosynthesis, transpiration rate, instantaneous water use efficiency and dry matter accumulation in kernels. Genotypes were ranked according to the heat susceptibility index (HSI): Amedeo, Arcangelo, Capeiti 8, Svevo and Trinakria resulted heat‐tolerant. These varieties were characterized by an early trigger of dry matter accumulation in kernels under HS (Amedeo, Arcangelo and Trinakria), or showed similar length of the GFD (Capeiti 8) between environments. The multilocation trial confirmed a negative relationship between maximum temperatures and grain yield, and a positive relationship between minimum temperatures and protein content during grain–filling periods. Research focusing on agronomic strategies, phenology and breeding for tolerance to heat stress is of strategic importance to cope with the detrimental effect of global warming in semi‐arid climates.

Foliar Brassinolide Sprays Ameliorate Post-Silking Heat Stress on the Accumulation and Remobilization of Biomass and Nitrogen in Fresh Waxy Maize

“…The grain NC was increased by HS in both hybrids without BR application. This result was consistent with studies on mature cereal crops [48,49]. The grain NC may have increased because the effect of HS on carbon/starch accumulation was more severe than that of nitrogen [49,50].…”

Performances of Durum Wheat Varieties Under Conventional and No-Chemical Input Management Systems in a Semiarid Mediterranean Environment

“…Creso in the second, and Svevo in the first year, both under conventional (12.7% and 12.6%), and Duilio under conventional and Claudio under no-chemical input in second year (10.7%) showed the significantly highest and lowest values overall. In general, protein content was slightly higher at the first year due probably to a warmer growing season; it has been shown that higher temperatures after anthesis favors higher rates of grain nitrogen accumulation, and/or lower rates of carbohydrate accumulation [9,[40][41][42]. Only Creso and Svevo presented almost one-point increase in protein content under conventional regimes.…”

“…According to the increased importance of durum wheat along the cereal food/feed chains, a number of breeding programs have been implemented aiming at developing new genotypes and exploit old cultivars, including landraces [9]. The assessment of the breeding progress for durum wheat in Spain and in Italy during the 20th century pointed out that the advantages were similar to those of other semi-dwarf's spring wheat and consisted essentially in the reduction in plant height and harvest index increase, with an enhancement of source/sink [10,11].…”

Integrated Analysis of Small RNA, Transcriptome, and Degradome Sequencing Reveals the Water-Deficit and Heat Stress Response Network in Durum Wheat

“…The negative impacts of reproductive-stage water deficiency on grain number are predominantly linked to the decrease of photosynthetic activity, which causes insufficient source supply to the reproductive tissues, eventually leading to floret abortion and failed grain formation [ 9 , 18 ]. In Italian durum wheat cultivars, just a small increase in mean minimum air temperature post-anthesis caused grain yield reduction by up to 22.6% [ 19 ]. Significant genotypic differences in yield performance were observed between modern and traditional cultivars, mainly attributed to differences in their leaf traits, such as net photosynthesis rate and transpiration rate [ 19 ].…”

“…In Italian durum wheat cultivars, just a small increase in mean minimum air temperature post-anthesis caused grain yield reduction by up to 22.6% [ 19 ]. Significant genotypic differences in yield performance were observed between modern and traditional cultivars, mainly attributed to differences in their leaf traits, such as net photosynthesis rate and transpiration rate [ 19 ]. Although water-deficit stress and high temperature are commonly coupled in the field, their combined effects can be quite different from their individual impact [ 1 , 8 ].…”