Genotypic variation in biomass allocation in response to field drought has a greater affect on yield than gas exchange or phenology

BMC Plant Biology

Research Article

Christine E. Edwards¹  Brent E. Ewers²  Cynthia Weinig³ 

[1] Department of Botany, University of Wyoming, 82071, Laramie, WY, USA;Current Address: Center for Conservation and Sustainable Development, Missouri Botanical Garden, PO Box 299, 63166, St. Louis, MO, USA;Department of Botany, University of Wyoming, 82071, Laramie, WY, USA;Program in Ecology, University of Wyoming, 82071, Laramie, WY, USA;Department of Botany, University of Wyoming, 82071, Laramie, WY, USA;Program in Ecology, University of Wyoming, 82071, Laramie, WY, USA;Department of Molecular Biology, University of Wyoming, 82071, Laramie, WY, USA;

关键词: Brassica rapa;    Genotype by environment interactions;    Drought escape;    Dehydration avoidance;    QTL;   

DOI  :  10.1186/s12870-016-0876-3

 received in 2016-05-20, accepted in 2016-08-16,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundPlant performance in agricultural and natural settings varies with moisture availability, and understanding the range of potential drought responses and the underlying genetic architecture is important for understanding how plants will respond to both natural and artificial selection in various water regimes. Here, we raised genotypes of Brassica rapa under well-watered and drought treatments in the field. Our primary goal was to understand the genetic architecture and yield effects of different drought-escape and dehydration-avoidance strategies.ResultsDrought treatments reduced soil moisture by 62 % of field capacity. Drought decreased biomass accumulation and fruit production by as much as 48 %, whereas instantaneous water-use efficiency and root:shoot ratio increased. Genotypes differed in the mean value of all traits and in the sensitivity of biomass accumulation, root:shoot ratio, and fruit production to drought. Bivariate correlations involving gas-exchange and phenology were largely constant across environments, whereas those involving root:shoot varied across treatments. Although root:shoot was typically unrelated to gas-exchange or yield under well-watered conditions, genotypes with low to moderate increases in root:shoot allocation in response to drought survived the growing season, maintained maximum photosynthesis levels, and produced more fruit than genotypes with the greatest root allocation under drought. QTL for gas-exchange and yield components (total biomass or fruit production) had common effects across environments while those for root:shoot were often environment-specific.ConclusionsIncreases in root allocation beyond those needed to survive and maintain favorable water relations came at the cost of fruit production. The environment-specific effects of root:shoot ratio on yield and the differential expression of QTL for this trait across water regimes have important implications for efforts to improve crops for drought resistance.

【 授权许可】

CC BY   
© The Author(s). 2016