Genetic mapping and physiological characterization of water-use efficiency in barley (Hordeum vulgare L.) on the Canadian Prairies

  • Author / Creator
    Chen, Jing
  • Temporal or seasonal water deficit is one of the major factors limiting crop yield on the Canadian Prairies. Empirical knowledge suggests that carbon isotope discrimination (Δ13C), through its negative relationship with water-use efficiency (WUE), is a good index for selecting crop varieties with stable yield in some rain-fed environments. Identification of quantitative trait loci (QTL) and linked markers for leaf Δ13C will help select genotypes with improved WUE in breeding programs. This thesis research investigated the genetic and physiological determinants of Δ13C variation in Canadian spring barley (Hordeum vulgare L.) and used two recombinant inbred line (RIL) mapping populations, including 200 RILs of W89001002003 × I60049 (six-row type) and 127 RILs of Merit × H93174006 (two-row type) to identify QTLs and their linked molecular markers for the trait. The parental lines used to produce the mapping populations and several of the RILs maintained consistent ranking of leaf Δ13C across years and in different experiments. The broad-sense heritability of leaf Δ13C was 0.8, suggesting stability of this trait under the environments studied. Leaf Δ13C was positively correlated with stomatal conductance (gs) in both greenhouse and field experiments, suggesting that gs caused most of the variation in leaf Δ13C. Low leaf Δ13C genotypes such as ‘CDC Cowboy’ and RIL ‘147’ achieved high WUE and yield by maintaining a high photosynthesis rate at a low gs, which suggests that it is possible to select low Δ13C genotypes that can maintain high yield under low moisture conditions. Using two mapping populations and phenotypic data for leaf Δ13C and agronomic traits collected from 4 different field environments, a total of 12 (six-row population) and 5 (two-row population) QTLs for leaf Δ13C were detected. A transgressive segregation pattern for leaf Δ13C was observed among RILs. For the six-row RILs, a major QTL for leaf Δ13C co-located with several agronomic traits on chromosome 3H near SSR marker Bmag606 (9.3, 9.4 and 10.7 cM interval) was identified across environments. This marker when validated may be useful in breeding programs for improving WUE and yield stability of barley on the Canadian Prairies.

  • Subjects / Keywords
  • Graduation date
    Fall 2011
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.