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- Title
Phenotyping of wheat cultivars for heat tolerance using chlorophyll a fluorescence.
- Authors
Sharma, Dew Kumari; Andersen, Sven Bode; Ottosen, Carl-Otto; Rosenqvist, Eva
- Abstract
In view of the global climate change, heat stress is an increasing constraint for the productivity of wheat (Triticum aestivum L.). Our aim was to identify contrasting cultivars in terms of heat tolerance by mass screening of 1274 wheat cultivars of diverse origin, based on a physiological trait, the maximum quantum efficiency of PSII (F [sub v] /F [sub m] ). A chlorophyll fluorescence protocol was standardised and used for repeated screening with increased selection pressure with a view to identifying a set of cultivars extreme for the trait. An initial mass screening of 1274 wheat cultivars with a milder heat stress of 38°C in 300 µmol m [sup -2] s [sup -1] for 2 h with preheating at 33-35°C for 19 h in 7-14 µmol m [sup -2] s [sup -1] light showed a genetic determination of 8.5 ± 2.7%. A heat treatment of 40°C in 300 µmol m [sup -2] s [sup -1] for 72 h in the second screening with 138 selected cultivars resulted in larger differentiation of cultivars with an increased genetic component (15.4 ± 3.6%), which was further increased to 27.9 ± 6.8% in the third screening with 41 contrasting cultivars. This contrasting set of cultivars was then used to compare the ability of chlorophyll fluorescence parameters to detect genetic difference in heat tolerance. The identification of a set of wheat cultivars contrasting for their inherent photochemical efficiency may aid future studies to understand the genetic and physiological nature of heat stress tolerance in order to dissect quantitative traits into simpler genetic factors. A chlorophyll fluorescence protocol was standardised and used for mass screening of 1274 wheat cultivars under heat stress. The screening was repeated three times with increasing selection pressure to identify the contrasting set of cultivars with increased genetic determination of the genotype variation. Chlorophyll fluorescence parameters were evaluated for their ability to detect genetic differences between wheat cultivars. The results are important for further studies to understand the genetic nature of heat stress tolerance.
- Subjects
WHEAT breeding; CULTIVARS; PHYSIOLOGICAL effects of heat; PLANT genetic engineering; CHLOROPHYLL
- Publication
Functional Plant Biology, 2012, Vol 39, Issue 11, p12
- ISSN
1445-4408
- Publication type
Article
- DOI
10.1071/FP12100