Adapting wheat in Europe for climate change

Abstract

Increasing cereal yield is needed to meet the projected increased demand for world food supply of about 70% by 2050. Sirius, a process-based model for wheat, was used to estimate yield potential for wheat ideotypes optimized for future climatic projections for ten wheat growing areas of Europe. It was predicted that the detrimental effect of drought stress on yield would be decreased due to enhanced tailoring of phenology to future weather patterns, and due to genetic improvements in the response of photosynthesis and green leaf duration to water shortage. Yield advances could be made through extending maturation and thereby improve resource capture and partitioning. However the model predicted an increase in frequency of heat stress at meiosis and anthesis. Controlled environment experiments quantify the effects of heat and drought at booting and flowering on grain numbers and potential grain size. A current adaptation of wheat to areas of Europe with hotter and drier summers is a quicker maturation which helps to escape from excessive stress, but results in lower yields. To increase yield potential and to respond to climate change, increased tolerance to heat and drought stress should remain priorities for the genetic improvement of wheat.

Keywords: A, maximum area of flag leaf area; ABA, abscisic acid; CV, coefficient of variation; Crop improvement; Crop modelling; FC, field capacity; GMT, Greenwich mean time; GS, growth stage; Gf, grain filling duration; HI, harvest index; HSP, heat shock protein; Heat and drought tolerance; Impact assessment; LAI, leaf area index; Ph, phylochron; Pp, photoperiod response; Ru, root water uptake; S, duration of leaf senescence; SF, drought stress factor; Sirius; Wheat ideotype.

Fig. 1

Normalised cultivar parameters of the best wheat ideotypes optimised for the 2050(A1B) climate scenario at 10 European sites. Site IDs are given in Table 1, descriptions of cultivar parameters – in Table 2.

Fig. 2

(A, B) anthesis and maturity dates (day of year), and (C, D) grain yields with 95-percentiles (presented as top error bars) and harvest index (HI) as simulated by Sirius using current wheat cultivars (A, C) and future wheat ideotypes (B, D) for the HadCM3(A1B) climate scenario at 10 European locations. Information about sites is given in Table 1.

Fig. 3

(A, B) 95-percentile of drought stress index (DSI) and soil water deficit at anthesis, (C, D) probability of maximum temperature to exceed 30 °C at anthesis or 5 days after anthesis as simulated by Sirius using current wheat (A, C) cultivars and future wheat ideotypes (B, D) for the HadCM3(A1B) climate scenario at 10 European locations. Information about sites and wheat cultivars used is given in Table 1.

Fig. 4

Effect of day temperature and water availability (● = irrigated to field capacity; ˆ = irrigation withheld) during 3 day transfers to controlled environment cabinets during booting on grain yield and yield components in winter wheat (each point is the mean of 11 genotypes, an average of 4 replicate pots and four plants per pot from Experiments 2 and 3 (Table 3)). Error bars are ±S.E.M. (70 d.f.).

Fig. 5

Effect of day temperature and water availability (● = irrigated to field capacity; ˆ = irrigation withheld) during 3 day transfers to controlled environment cabinets during booting on grain yield and yield components in winter wheat (each point is the mean of 11 genotypes, 2 replicate pots and four plants per pot from Experiment 2 (Table 3)). Error bars are ±S.E.M. (22 d.f.).

Fig. 6

Effect of ear growth stage on spikelet fertility and mean grain weight of wheat when exposed to 20 °C (solid) and 40 °C (open) with irrigation. Each bar is the mean of 11 genotypes, 2 replicate pots and four plants per pot from the anthesis treatment in Experiment 2 (Table 3). Error bars are 1 S.E.M. (22 d.f.).

Fig. 7

Effect of day temperature during 3 day transfers to controlled environment cabinets during anthesis on (A) grain yield, (B) grains per spikelet, and (C) mean grain weight of Southern European (■ = MV Emese, ▲ = Renesansa) and UK wheats (□ = Mercia, △ = Savannah). Points are means of 6 replicate irrigated pots and four plants per pot from Experiment 1 (Table 3). Error bars are 1 S.E.M. (35 d.f.).

Fig. 8

Relationship between the proportion of spikelets from ears at full anthesis and performance of near-isogenic lines (NIL) of cv. Mercia varying for reduced height alleles (Rht) after 3-day transfers to 36°C/28 °C, 16 h day/night controlled environments with (solid) and without (open) irrigation. Squares = GA-sensitive alleles, Circles = GA-insensitive alleles. Each point is the mean for a NIL over two replicate pots, and four plants per pot from Experiment 2 (Table 3). Error bars are one SEM for without (left) and with (right) irrigation.