1. 9/19/2016 Abstract: Durum Wheat Genotypes Differ in Their Mesophyll Conductance Response to Drought and Temperature. (ASA, CSSA and SSSA International …
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195­1 Durum Wheat Genotypes Differ in Their Mesophyll Conductance Response to
Drought and Temperature.
See more from this Division: C02 Crop Physiology and Metabolism
See more from this Session: C­2/C4 Graduate Student Oral Competition ­ III
Tuesday, November 8, 2016: 8:00 AM
Phoenix Convention Center North, Room 123
Mesfin Kebede Gessese1, Harbans S. Bariana2, Urmil K. Bansal2 and Margaret M. Barbour3, (1)Plant Breeding Institute, The
University of Sydney, Faculty of Agriculture and Environment, Cobbitty, AUSTRALIA
(2)Plant Breeding Institute, The University of Sydney, Faculty of Agriculture and Environment, Narellan, Australia
(3)Environmental sciences, Faculty of Agriculture, Centre for Carbon Water and Food; The University of Sydney, Cobbitty, Australia
Abstract:
In order to mitigate the impacts of global warming and maintain sustainable crop production, selection for water­use efficient and heat
tolerant crops is imperative. Increased conductance to CO2 from the intercellular air spaces to the chloroplasts (mesophyll
conductance, gm) should increase photosynthetic rate without a water use cost, resulting in increased leaf intrinsic water­use efficiency
(WUEi). Genetic variation in gm has been demonstrated within cereal crops, and gm has been shown to be reduced by drought in
some species. Further, the temperature sensitivity of gm varies considerably between species. If increased gm is to be included in
breeding programs for increased water­use efficiency, the genotype ranking for the trait must be determined under a range of
environmental conditions. Using genotypes of durum wheat grown under well­watered and water­limited conditions, we assessed the
response of gm to drought and short­term temperature changes and the influence of gm on WUEi. Drought reduced gm in all but one
genotype, and drought significantly altered the temperature response of gm by reducing the thermal optima. As expected drought
increased WUEi, driven by reduced stomatal conductance, but the degree of response differed between genotypes. gm and WUEi
responded similarly to leaf temperature under well­watered conditions. In general, increased gm facilitated supply of CO2 to
chloroplasts to maintain photosynthetic rate as stomatal conductance decreased in response to increasing leaf temperature. However,
the gm influence on WUEi varied between genotypes and with water availability.
See more from this Division: C02 Crop Physiology and Metabolism
See more from this Session: C­2/C4 Graduate Student Oral Competition ­ III
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