CSIRO is releasing two new conventional and four new Bollgard II varieties to the industry for the 2003 planting. All these varieties will be available through Cotton Seed Distributors in the coming season. Following are details on the new varieties and where we recommend they are grown.

NEW CONVENTIONAL VARIETIES

Sicala 45 offers growers a significant advance in Fusarium resistance in a medium maturity variety. Sicala 45 has on average a two per cent higher yield than Sicala 40 and is ideal for the Darling Downs, Goondiwindi, Moree, and Warren where Fusarium wilt is present. In six trials over four years under heavy incidence of Fusarium wilt on the Darling Downs, Sicala 45 yielded 36 per cent more than Sicot 189 and 77 per cent more than Sicala 40.

The F-rank for Sicala 45 is 154, averaged over eight trials in Fusarium nurseries. Sicala 45 has good Verticillium wilt resistance and some resistance to Alternaria and premature senescence. The fibre quality of Sicala 45 is good with long strong fibre with an intermediate micronaire.

Siokra V-18 is a new okra leaf variety that offers the same resistance to Fusarium wilt as Sicot 189 (F-rank for Siokra V-18 is 107(8)). Siokra V-18 is a medium maturity variety with four per cent greater yield than V-17 in the absence of Fusarium wilt and 40 per cent more when grown in Fusarium-infested nurseries.

It also has an improved fibre package with longer fibre. Siokra V-18 is adapted to central, eastern and southern regions. It has good resistance to Verticillium wilt and some resistance to Alternaria and premature senescence. It has similar standability to Siokra V-17. Siokra V-18 is an option for dryland systems in shorter season areas such as the eastern Darling Downs where Fusarium wilt is present or threatened, and where an okra leaf is required for pest management and water use efficiency.

BOLLGARD II VARIETIES

Bollgard II technology will be introduced over the next two seasons. Four new CSIRO Bollgard II varieties will be available to growers in the 2003 season.

Sicot 11B is a relatively early plant type with large bolls. It has slight resistance to Fusarium wilt and good resistance to Verticillium wilt. It has an excellent fibre package, with above average length, good strength and an intermediate micronaire. Sicot 11B is suited to short season production areas and systems free of Fusarium wilt.

Sicot 12B is an early to medium maturing variety with intermediate growth habit and small to medium sized bolls. Yield of Sicot 12B has been very good in areas from the Namoi Valley south. It has some Fusarium resistance making it suited to locations such as the Macquarie and upper Namoi. Fibre quality of Sicot 12B is also good with long fibre, adequate strength and intermediate micronaire.

Sicot 13B is a medium maturing taller plant type with average boll size. It has good yield potential but a low Fusarium resistance ranking and should therefore be grown only in regions free of Fusarium wilt such as Tandou, the lower Namoi and Emerald. Fibre quality is similar to Sicot 289i, including a relatively high micronaire so crop management should take that fact into consideration. In limited dryland trials so far, Sicot 13B has been the best Bollgard II variety available for 2003.

Sicot 14B is a medium maturing compact plant type with average boll size. In longer season locations, agronomic management should ensure full plant size is obtained. The Fusarium resistance ranking of Sicot 14B is the best of Bollgard II varieties available in 2003. In three years of trials so far, Sicot 14B has been equal to or better than Sicot 189 in Fusarium resistance ranking and yield under heavy Fusarium wilt pressure.

As a result Sicot 14B will be the safest disease management option for Bollgard II in the lower Macquarie, Bourke, St George, Gwydir, Macintyre and Darling Downs regions. Fibre quality of Sicot 14B is similar to Sicot 289i, except for the benefit in hot areas of having lower micronaire.

These varieties provide an introduction to this technology which is aimed at improving Bt resistance management in Helicoverpa. The next two years will see a number of additional Bollgard II varieties released, many of them stacked with Roundup Ready.