Cotton Breeding Australia
Core Breeding III / Quality Assurance III / Darling Downs Fusarium Nursery II
Warwick Stiller, Shiming Liu, Heidi Clements, Greg Constable, Peter Reid, Danny Llewelyn (QA).
This project has delivered significant industry outcomes in the form of new varieties and trait packages that have completely displaced previous varieties and traits.
Five new varieties containing Bollgard 3/RRF have been released, with Sicot 714B3F, Sicot 746B3F and Sicot 748B3F having particular commercial success. While not widely grown, Sicot 754B3F has proved itself with a premium fibre package that has enabled some growers and merchants to achieve significant price premiums. Sicot 707B3F was the first variety to be released directly for the southern growing regions, specifically to address low micronaire concerns.
Two new varieties containing Roundup Ready Flex were released - Sicot 711RRF which replaced Sicot 71RRF and Sicot 812RRF which has better staple specifically for the dryland industry.
Two new conventional lines were also delivered to CSD - CSX5432 and CSX8308. These are high performing lines that address the concerns of some growers that we are not providing choice and locking them in to having to grow varieties with GM traits.
Detailed Research Results
Bollgard 3/RRF (B3F)
Up to 2017/18, CSIRO has developed more than 50 breeding families with the B3F trait combination to provide a range of options into the future.
This B3F breeding material is derived from new elite conventional lines and aims to offer improvements in yield, regional or system adaptation, fibre quality and disease resistance. This material will form the basis of new introgression for B3XF families.
XtendFlex developmentSince 2012, CSIRO has been working to develop elite germplasm that contains Monsanto’s XtendFlex trait. This trait provides tolerance to Dicamba and glufosinate and is paired with the existing RRF trait, with or without Bollgard 3.
Fifteen families are now at various stages of development, with the first set of lines in replicated trials in 2016/17. It is expected that this initial family will produce a ‘concept’ product (which is not intended to be a commercial product) to be used to further evaluate and refine the herbicide system in Australia.
Due to the loss of disease screening Nurseries because of hail &/or low expression of disease over the last two seasons, screening will continue over the coming years to refine selections prior to commercialisation. These lines were in CSD nursery production in 2017/18.
Development is also underway for lines containing XtendFlex alone. Because the XtendFlex donor also contained Bollgard II, it has taken considerable work to remove those traits from these families.
Good progress is being made in the development of a wide suite of conventional germplasm to address CSIRO breeding targets. In particular CSIRO are conscious of having options for future production systems, as well as platforms for future transgenic traits. In 2013/14, the breeding program moved to having an Advanced Line Trial which contains the best lines from each of the breeding programs in the one experiment at all sites. This has reduced duplication of control varieties in experiments and enables better evaluation of the most advanced lines.
Improved combination of fibre traits
CSIRO are also studying the association between yield and fibre quality to (a) understand reasons for the negative association and (b) to design a breeding approach to identify high quality lines with better yield. Good progress is being made in both objectives. For cotton to remain competitive amongst synthetic fibres, cotton fibre quality must be improved, but not at the expense of yield reductions.
The current targets CSIRO are aiming for are >1.24 inch length; >32 g/tex strength; <180 ug/m fineness; and target yield within 5% of Sicot 71.