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Identification of heat tolerant wheat lines showing genetic variation in leaf respiration and other physiological traits

Pinto, R. Suzuky, Molero, Gemma, Reynolds, Matthew P.
Euphytica 2017 v.213 no.3 pp. 76
biomass, canopy, cell respiration, flowering, genetic variation, genotype, heat tolerance, landraces, leaves, normalized difference vegetation index, phenotype, plant age, plant breeding, spring wheat, temperature
A total of 140 diverse spring wheat lines were characterized for agronomic and physiological traits under hot field conditions, and a subset of thirteen were selected for dark leaf respiration studies (Rd). These genetic resources included synthetic-derived lines, landraces, landrace-derived lines, bread wheats, and durum wheats. Initial phenotyping showed that better heat-adapted genotypes (best yielding) exhibited high early biomass (assessed by normalized difference of vegetative index, NDVI), high grainfilling rates, and low canopy temperatures. As for other studies Rd increased as temperature increased (within the range of 15–40 °C), and decreased with plant age. Correlations between Rd and leaf temperature ranged between 0.50 and 0.85. Rd was negatively associated with yield when recorded at 30–35 °C during anthesis and grainfilling. Comparisons between wheat groups showed that synthetic-derived materials expressed lower leaf respiration rates and larger yields than the other groups at warm temperatures.