Two of the Western Australia Department of Agriculture’s newest wheat varieties EGA Eagle Rock and Tammarin Rock have demonstrated maximum grain yield potential when sown between mid-May and mid-June.

The Department conducted 18 trials cross the northern, southern, central and south coast regions in 2003-2004.

The trials were undertaken to determine the best times to sow new wheat varieties to achieve maximum grain yield, given the different seasonal breaks across the state.

Results of the trials were presented by Department research agronomist Darshan Sharma at Agribusiness Crop Updates.

Dr Sharma said the trials aimed to highlight the performance of new wheat varieties, and determine the variety-specific sowing period in order to achieve maximum yield in a given environment.

He said the trial plots were located in Mullewa, Mingenew, Eradu, Mukinbudin, Nungarin, Quairading, Avondale, Nyabing, Jerramungup, Katanning, Salmon Gums, Gibson and Scadden.

“Trial results show that Annuello, Calingiri, Chara, Datatine, Drysdale, EGA Jitarning, Odiel and Rees and the crossbreds RAC1055, EGA 2248 could be sown up to early June in most parts of the State without further delaying the seeding program. Calingiri demonstrated the earliest start of mid-May.

“The optimum sowing periods for other mainstream varieties Carnamah, Westonia and Wyalkatchem were mid-May to mid-June, which coincides with the most common seasonal break time throughout the state.

“The new varieties EGA Eagle Rock, Tammarin Rock (released this week at Crop Updates) and WAWHT2524 (scheduled to be released in August 2005) are also best sown between mid-May to mid-June.

“Bowerbird, GBA Ruby, GBA Shenton and EGA Bonnie Rock had optimum sowing times between late-May to mid-June in most parts of the state.”

Dr Sharma said the trial results provided growers with a guide as to the most suitable variety to be sown in a particular region.

“A specific, detailed breakdown of the trial results has been developed for each region and these results will also be presented at Regional Crop Updates,” he said.

The Grains Research and Development Corporation supported the wheat trial project and is also a major supporter of the Department’s Agribusiness Crop Updates.

Table 1. Optimum sowing time of different varieties in the four wheat growing regions of Western Australia. A full table of results, encompassing all varieties trialled, will be presented at Agribusiness Crop Updates.

MM= mid-May (10-20 May), LM= late May (21-31 May), EJ= Early-June (1-10 June), MJ= mid-June (11-20 June), LJ= late-June (21-30 June); Values within brackets show the number of data points on which the conclusion is based. Less confidence can be placed on estimates made on less than 10 observations.