July 2, 2003

from Cotton Communications / CottonWorld

COTTON Seed Distributors has completed its most comprehensive ranking of varieties for Fusarium and Verticillium wilt tolerance.


This week: Robert Baird of Queensland Cotton and Jim Prendergast of Namoi Cotton outline the importance of fibre quality to spinners of Australian cotton

Refuge Requirements: Calculate your INGARD® /Bollgard® II refuge requirements for 2003/04. See Latest FAQ at www.csd.net.au

Disease rankings:

The 24 CSD varieties for the coming season include four new Bollgard II varieties and two new conventional varieties.

About a third of all CSD varieties listed have above-baseline rankings for either disease, and a quarter of all varieties are above baseline for both diseases.

The best available varieties for fusarium resistance are two new varieties available for the first time this season: Sicala 45 (ranking 154), followed by the new Bollgard II variety Sicot 14B (ranking 141).

They are followed by Sicot 80 and Sicot 42i, each with rankings of 116, Sicot 289rri (114), Siokra V-18 and Sicot 71 (107), and Sicot 289i (101).

The best available varieties for verticillium resistance are Sicot 289rri (ranking 110), Sicot 80 and Siokra V-18 (109), Sicala 45 (108), the new Bollgard variety Sicot 12B (104), and Sicot 289i and the new Bollgard variety Sicot 14B (102).

The best varieties with combined resistance for both fusarium and verticillium wilt include Sicala 45, Sicot 14B, Sicot 289rri. Sicot 80 and Siokra V-18.

Protocol:

The disease rankings were compiled from a standard industry protocol developed by a committee comprising seed companies, Australian Cotton CRC plant pathologists, and CSIRO.

Fusarium resistance has been calculated relative to the performance of the CSD variety Sicot 189 (ranking 100), while verticillium resistance is expressed relative to the performance of Sicala V-2 (ranking 100).

The purpose of the rankings is to provide cotton growers with a quantitative measure of the relative resistance or susceptibility of new or existing cultivars, based on the survival of plants in the presence of significant disease pressure.

The full spreadsheet of disease rankings for both fusarium and verticillium for all CSD varieties, which is updated as new trial information comes to hand, is available on the CSD website www.csd.net.au under the Agonomy Tools heading.