|OVENDEN, BEN - Nsw Department Of Primary Industries
|MILGATE, A - Nsw Department Of Primary Industries
|LISLE, C - University Of Wollongong
|WADE, L - Charles Sturt University
|REBETZKE, G - Commonwealth Scientific And Industrial Research Organisation (CSIRO)
|Holland, Jim - Jim
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/2017
Publication Date: 11/1/2017
Citation: Ovenden, B., Milgate, A., Lisle, C.J., Wade, L.J., Rebetzke, G.J., Holland, J.B. 2017. Selection for water-soluble carbohydrate accumulation and investigation of genetic × environment interactions in an elite wheat breeding population. Theoretical and Applied Genetics. 130:2445-2461.
Interpretive Summary: Breeding for improved yield under drought is difficult because yield becomes very inconsistent. Plant physiologists have sought to identify traits that are correlated with yield under drought conditions, but which can be measured more accurately to permit more efficient selection for yield under drought. One such traits is water-soluble carbohydrate concentration in stems of wheat plants, a measure of the sugars that the plant is capable of producing under water-limited conditions. In this study, we measured these sugar levels and other important agronomic traits across eight environments, of which two were severely water-limited. The relative levels of carbohydrates were quite consistent among well-watered environments but not consistent between well-watered and drought environments. We found that carbohydrate levels were not strongly correlated with yield under either well-watered or drought conditions in this set of wheat breeding lines, suggesting that measuring the carbohydrates is not expected to be better at identifying optimal varieties compared to directly measuring their yields in the target environment.
Technical Abstract: The potential to increase the genetic capacity for water-soluble carbohydrate (WSC) accumulation is an opportunity to improve the drought tolerance capability of rainfed wheat varieties, particularly in Australia where terminal drought is a significant constraint to wheat production. A population of elite breeding germplasm was characterised to investigate the potential for selection of improved WSC concentration and total amount in water deficit and well-watered environments. Accumulation of WSC involves complex interactions with other traits and the environment. For both WSC concentration (WSCC) and total WSC per area (WSCA), strong genotype-environment interactions were reflected in the clear grouping of experiments into well-watered and water deficit environment clusters. Genetic correlations between experiments were high within clusters. Heritability for WSCC was larger than for WSCA, and significant associations were observed in both well-watered and water deficit experiment clusters between the WSC traits and nitrogen content, tillering, grains per m2 and grain size. However, correlations between grain yield and WSCC or WSCA were weak and variable, suggesting that selection for these traits is not a better strategy for improving yield under drought than direct selection for yield.