Estoc a replacement for Yitpi

AGT senior wheat breeder Dr Haydn Kuchel said the new release - Estoc - tested as RAC1412, was closely related to the popular wheat, Yitpi, but provided stronger resistance to stem rust.

"RAC1412 has been in the breeding program for nine years," he said.

"It has a similar maturity to Yitpi, and a later maturity compared with other varieties released recently.

"It offers improved stem rust resistance along with good stripe and leaf rust resistance.

"Apart from its good grain size, good test weights and low screenings, it also has the sprouting tolerance of Yitpi."

Dr Kuchel said the APW grade variety offered SA and Victorian growers the opportunity of improved risk management in their wheat production.

"Stem rust poses one of the most damaging threats to wheat production in southern Australia and has flared up under this year's conducive conditions," he said.

"While it has only developed late in the season and caused minor damage, it has significantly increased the potential impact of stem rust on future crops.

"Most alternative varieties to Estoc that offer improved stem rust resistance when compared with Yitpi, unfortunately, also have significant weaknesses such as greater susceptibility to stripe rust, pre-harvest sprouting susceptibility, earlier flowering, lower grain yield and reduced physical grain quality."

Dr Kuchel said Estoc was the result of a targeted breeding effort to produce a low-risk alternative to Yitpi.

"Trial work indicates Estoc offers a small yield improvement over Yitpi in favourable conditions, while yielding significantly better in tougher seasons and environments," he said.

"Like Yitpi, Estoc provides a good level of boron toxicity tolerance - a major subsoil constraint in southern Australian soils.

"Its medium to late maturity makes Estoc a good management option in frost-prone areas.''

Dr Kuchel said the increased incidence of pre-harvest sprouting due to the conditions in the last two seasons had become a genuine concern for growers and Yitpi was recognised as offering less risk to sprouting than some other varieties.

And, with test weight receival standards expected to increase from 74 kilograms a hectolitre to 76kg/hl from the 2012 harvest, the risk of downgrading with some varieties that inherently produce lower test weights will increase.

Estoc seed is available in commercial quantities for the 2011 season through AGT affiliates and seed retailers.

Meanwhile, AGT has three Clearfield wheats ready for release, offering improved levels of tolerance to imidazolinone herbicides and more options for in-crop weed management. They are awaiting completion of a licence agreement and the Australian Pesticides and Veterinary Medicines Authority registration of Intervix for use on Clearfield wheat.

AGT marketing manager for SA and Vic, Dan Vater, said 350 tonnes of seed would likely be available next season for each of the varieties - RAC 1669, RAC 1671 and RAC 1683.

RAC1669 is a Gladius type with a slightly earlier maturity and similar disease package but with improved Cereal Cyst Nematode resistance. It has a preliminary APW/AH quality classification.

RAC 1671 is also a Gladius type with a similar maturity to Correll and offers similar yields to Gladius. It also has preliminary APW/AH quality classification.

RAC 1683 offers mid-season maturity, similar to Correll. It is derived from the Spear and Gladius families. While it performs well under most conditions, like the Spear family of wheats, it shows its highest relative yields in medium to high rainfall areas. Again, this wheat has APW/AH preliminary classification.

Hybrid wheat breeder Michael Quinn said AGT was also working on a Clearfield durum with imi-herbicide resistance, with Hyperno and Saintly backgrounds.

"Hopefully, in a couple of years, we'll have a Clearfield Saintly or Hyperno," he said.