QTL mapping of chromosomal regions conferring reproductive frost tolerance in barley (Hordeum vulgare L.)

Abstract

Spring radiation frost is a major abiotic stress in southern Australia, reducing yield potential and grain quality of barley by damaging sensitive reproductive organs in the latter stages of development. Field-based screening methods were developed, and genetic variation for reproductive frost tolerance was identified. Mapping populations that were segregating for reproductive frost tolerance were screened and significant QTL identified. QTL on chromosome 2HL were identified for frost-induced floret sterility in two different populations at the same genomic location. This QTL was not associated with previously reported developmental or stress-response loci. QTL on chromosome 5HL were identified for frost-induced floret sterility and frost-induced grain damage in all three of the populations studied. The locations of QTL were coincident with previously reported vegetative frost tolerance loci close to the vrn- H1 locus. This locus on chromosome 5HL has now been associated with response to cold stress at both vegetative and reproductive developmental stages in barley. This study will allow reproductive frost tolerance to be seriously pursued as a breeding objective by facilitating a change from difficult phenotypic selection to high-throughput genotypic selection.

Quantitative Trait Loci and Crop Performance under Abiotic Stress: Where Do We Stand?: Table I.

“…In many parts of the world, frost at flowering time can also cause sterility or shriveled grains in cereals and other crops, leading to sporadic episodes of severe losses (Fuller et al, 2007). QTLs for reproductive frost tolerance have been reported in barley, near the Fr-H1 locus, and on chromosome arm 2HL (Reinheimer et al, 2004). However, efforts to breed for reproductive frost tolerance have met with comparatively little success, most likely due to the lack of sufficient genetic variation, the confounding effects of tiller developmental stage on susceptibility, and the dependence on frost simulation chambers for efficient phenotyping.…”

Structural and functional characterization of a winter malting barley

“…The candidate gene for Fr-H2 is one or more members of two physically linked clusters of at least 11 CBF genes Galiba et al 2009;Skinner et al 2005) whose expression is regulated by Fr-H1 ). Fr-H1 is not only important for LT tolerance at the vegetative stage, but also for reproductive-stage frost tolerance (Reinheimer et al 2004). Flt-2L, located in a region on chromosome 2H tracing to the cold-tolerant parent NE76129, is the other locus involved in this phenomenon of LT tolerance at the vegetative stage (Chen et al 2009;Reinheimer et al 2004).…”

“…Fr-H1 is not only important for LT tolerance at the vegetative stage, but also for reproductive-stage frost tolerance (Reinheimer et al 2004). Flt-2L, located in a region on chromosome 2H tracing to the cold-tolerant parent NE76129, is the other locus involved in this phenomenon of LT tolerance at the vegetative stage (Chen et al 2009;Reinheimer et al 2004). …”

Dissection and cytological mapping of barley chromosome 2H in the genetic background of common wheat

“…In this study we focused on chromosome 2H, which contains genes controlling a variety of traits of agronomic and commercial importance, such as cleistogamy (Turuspekov et al, 2004), reproductive frost tolerance (Reinheimer et al, 2004;Li et al, 2005), photoperiod response (Laurie et al, 1994), head architecture (Pourkheirandish et al, 2007), and the production of hordatines A and B, strong antifungal components in shoots of barley seedlings (Nomura et al, 1999(Nomura et al, , 2007. In the cytological map reported herein, the 2H chromosome was dissected into 34 regions and became the most finely dissected chromosome among the barley chromosomes so far dissected by the Gc system.…”