Assessing Long Coleoptile Genetics to Improve Wheat Establishment With Deep Sowing

GRDC - Author: G. Rebetzke (CSIRO Agriculture and Food), A. Fletcher (CSIRO Agriculture and Food), B. French (DPIRD Merredin WA), C. Zaicou-Kunesch (DPIRD Geraldton WA) and C. Wesley (Charlesville Ag, Southern Cross WA)

Type: Research Paper
Knowledge level: Advanced

Farm Table says:

The authors of this paper note in the conclusion: “Genes that increase coleoptile length have also been identified and tagged with molecular markers to facilitate their use in breeding programs. These genes are expected to play an important role in improving emergence from depth. Matching new genetics with appropriate agronomy and technologies such as moisture seeking, will help improve the emergence and establishment of deep-sown wheats, particularly when sown early in warmer soil conditions or when sown deep when chasing soil water when the top 100+mm of soil has dried out.  The net impact will be to widen the effective sowing window available to growers to sow and establish crops when sowing into soil moisture. This enables growers to better target specific optimal flowering windows for varieties to optimise competing yield and frost risk outcomes. The most likely useful new dwarfing genes, Rht13 and Rht18, have been bred into a range of current commercial wheats. Long coleoptile wheat breeding lines in Mace, LRPB ScoutEspada, EGA Gregory and Magenta genetic backgrounds have been delivered to Australian breeders for testing and use in breeding.”. Please access the full paper via the link below if this research interests you.

The take home messages from this GRDC funded research are below. Please access the full paper via the link below for methodology, references, acknowledgements and discussion.

  • Current Australian wheat cultivars contain dwarfing genes that reduce coleoptile length by 40%. New dwarfing genes are available that reduce plant height but don’t reduce coleoptile length
  • Deep-sowing studies in NSW and WA show benefit with new dwarfing genes in increasing emergence at sowing depths of up to 120mm but without changing plant height
  • Moisture-seeking points coupled with new genetics should reliably allow seed placement and emergence from sowing depths of 100mm or greater, and/or in warmer soils which reduce coleoptile length
  • Large, plump seed containing larger embryos should be used when sowing deep and/or where potential for soil crusting could impede seedling emergence.

Figure 1. Patterns of emergence of wheat genotypes with different dwarfing genes sown at target depths of 40, 80, or 120mm at Mullewa and Merredin in 2016 (after French et al. 2017).

2020 - Australia - GRDC - Author: G. Rebetzke (CSIRO Agriculture and Food), A. Fletcher (CSIRO Agriculture and Food), B. French (DPIRD Merredin WA), C. Zaicou-Kunesch (DPIRD Geraldton WA) and C. Wesley (Charlesville Ag, Southern Cross WA)
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