Genetic Variation for Tolerance to Terminal Heat Stress in Dasypyrum villosum

Abstract

Heat stress substantially reduces the grain yield and quality of wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD genome) and poses a major challenge to sustaining productivity because of global warming. Across wheat‐growing regions in the United States and globally, wheat often experiences terminal heat stress during the postflowering period. Dasypyrum villosum, a wild relative of wheat, has been a useful genetic resource for the improvement of several traits in wheat. Here we report a first survey of terminal heat tolerance in D. villosum. Twenty accessions of D. villosum from seven countries and three common wheat cultivars (checks) were compared. Agronomic traits including single kernel weight, total grain weight, grain number, and shoot weight were evaluated in both nonstress (22°C day, 17°C night) and heat stress (36°C day, 30°C night) conditions in two independent experiments. The results showed that there was significant genetic variation for heat tolerance during the grain‐filling period in D. villosum and that single kernel weight was less affected by heat stress in D. villosum than in common wheat. Three accessions, TA10228 and TA10225 originating in Italy and TA2172 in Turkey, showed the highest terminal heat tolerance. This work suggests that D. villosum may be a useful novel resource for the improvement of heat tolerance in common wheat.

Genetic variation for terminal heat stress tolerance in winter wheat

“…Briefly, the rationale stood on the observations that during the first 26 days after flowering the chlorophyll contents were not significantly changed under the control condition for hexaploid common wheat, tetraploid wheat and maize (Ristic et al, 2008). The rationale for using percentage of control rather than heat susceptibility index (HSI, Fischer and Maurer, 1978) was given in Fu et al (2015), and this method was later on used by Fu et al (2022); Fu et al (2017). Briefly, the rationale stood on the facts including (1) that percent of control is always non-negative and a HSI can be negative in some cases and a negative number can cause problems in some statistical analyses such as PROC GLIMMIX which lacks convergence for a negative number, and (2) percent of control for each accession is more intuitive and is unaffected by the group of accessions under evaluation and, in contrast, HSI is the opposite (Fu et al, 2015).…”

“…Ten days after anthesis, three pots randomly selected from each genotype were moved to a Conviron Model E-36 growth chamber and exposed to heat stress for 16 d (36°C day, 30°C night, ± 1°C; RH 90 to 100%; photoperiod 16 h; PPFD of 480 mmol m -2 s -1 ). This greenhouse condition and the heating chamber condition were used based on the previous work that these conditions were previously successfully used for identifying heat tolerant wheat lines (Ristic et al, 2007;Fu et al, 2017;Fu et al, 2022). Pots were placed randomly in the growth chamber.…”

Effects of post‐flowering heat stress on chlorophyll content and yield components of a spring wheat diversity panel

“…For each pot in the heat stress treatment, the chlorophyll retention at 4, 8, 12, or 16 d was expressed as a percentage of Day 0 (control). The rationale for using percentage of control rather than heat susceptibility index was detailed in Fu et al (2015Fu et al ( , 2017. The rationale for using chlorophyll content at Day 0 as the control was previously described in Ristic et al (2008).…”

“…The rationale for using percentage of control rather than heat susceptibility index was detailed in Fu et al. (2015, 2017). The rationale for using chlorophyll content at Day 0 as the control was previously described in Ristic et al.…”