Very dry spring conditions throughout much of SA last year were ideal for the recently released, very early maturing wheat variety Axe, to show its potential. Axe triumphed among 37 new and older commercial varieties tested at 25, SARDI managed, National Wheat Variety Trial sites across South Australia in 2008. The trials, funded by GRDC, also tested a further 37 advanced lines from wheat breeding companies operating throughout Australia.
While yields at two sites, Booleroo Centre and Geranium were very low and variable, and deemed invalid for comparison, the remaining 24 sites produced useful results and averaged 1.89 t/ha, similar to the average 1.87 t/ha produced in 2007.
This was not the first time that Axe has topped the list, having also led in 2006 and performing well in other dry seasons. Across all trial sites, the already widely established early variety, Wyalkatchem also performed well, trailing Axe by only 1 percent with other widely grown, later maturing varieties, like Yitpi, Pugsley and Frame, 9, 11 and 15 percent lower yielding respectively.
Despite being ahead overall in 2008, Axe and Wyalkatchem were very closely rivalled by a large number of new varieties in order Espada, Lincoln, Gladius, Guardian, Young, Wargan, Catalina and Peake with less than 5 percent difference in grain yield separating them all.
All of these top ranked varieties are in the range, early to mid season flowering. This was again like 2007, an advantage for survival and productivity throughout South Australia under the extremely dry conditions during late winter and spring. Together with dry conditions, frosts and some occurrences of stripe rust were additional factors influencing variety performance at some NVT sites in 2008.
Axe, released by AGT in 2007, was outstanding across Upper Eyre Peninsula and Murray Mallee sites where its excellent early vigour, very early flowering and plump grain size give it an immediate fit with growers. Axe remains a good option for very early finishing situations, is eligible for AH grade and shows good test weights and low screenings even under harsh conditions. It is susceptible to CCN and moderately susceptible to stem rust but has excellent stripe and leaf rust resistance.
In second place, the older APW variety Wyalkatchem produced surprising results but not unlike its top placing in 2004, when extremely dry spring conditions also prevailed. Wyalkatchem was among the top ranking varieties at most sites in 2008, dropping away where stripe rust occured but was particularly good throughout Eyre Peninsula where it remains popular with growers. While demonstrating that it can still compete with newer varieties for yield, Wyalkatchem does have shortcomings in foliar disease resistance. It is susceptible to the WA strain of stripe rust, although less so at higher temperatures, and is also susceptible to CCN and powdery mildew. Growers are cautioned on sowing Wyalkatchem exclusively, but it remains a useful option in drier districts and other less rust prone areas. Growers should monitor their crops and be prepared to spray with fungicides at the first signs of stem and stripe rust. A Wyalkatchem replacement with improved stem rust resistance, boron tolerance and CCN resistance will be widely available to South Australian growers for the 2010 season. This variety, Mace, will be tested in SA NVT for the first time in 2009.
The recently released variety, Espada, yielded similarly to Wyalkatchem in overall results and just 2 percent above its better known sister-line, Gladius. Espada was generally superior to Wyalkatchem in higher rainfall eastern districts and slightly behind in West Coast NVT trials. Over three years trialling, Espada has shown to be a useful, APW quality, rust resistant alternative particularly for medium to higher rainfall areas. It generally has slightly higher screenings and lower test weight than Gladius, is similarly moderately susceptible to CCN, but offers improved yellow spot and leaf rust resistance
The new mid season maturing variety, Lincoln, developed by Longreach breeders for south eastern Australia just trailed Espada overall. It showed good vigour and resilient yields under tight finishing conditions, particularly in low yielding districts such as Upper Eyre although state-wide yield results in 2007 were generally less impressive. Lincoln is eligible for AH grade, has excellent rust and yellow leaf spot resistance but is susceptible to CCN and crown rot. Lincoln grain size appears similar to Janz and averaged slightly higher screenings and test weight than Janz in 2008 trials.
The top yielding variety from 2007, Gladius, dropped back slightly in 2008 to average around 3 percent below Axe but still 6 percent above Yitpi. With grain size similar to Yitpi albeit slightly lower test weights, Gladius performed well in all districts to again demonstrate good tolerance to low rainfall environments with broad adaptation, high yield and good levels of resistance to all rusts. It also has boron and aluminium tolerance but is moderately susceptible to eelworm and quite susceptible to septoria. Previous research indicating Gladius to have a lower tolerance of Ally® and Hussar® herbicide was not observed in 2008 trials but growers are still cautioned on these combinations. Like most varieties, Gladius is susceptible to sprouting and a study of grain from all trials harvested in 2008 did not show any difference when compared to Wyalkatchem and Yitpi. Over four seasons in SA, Gladius has produced unsurpassed yields and profitability within trials, to ensure a wide appeal to wheat growers.
At equal fifth placing overall in 2008 trials and 4 percent below Axe, were the new varieties, Wargan, Guardian and Young. Developed for NSW, Wargan is a very early maturing variety derived from Janz with ASW quality and released by AGT. While it has good rust resistance, grain size within 2008 trials was similar to Janz and it is unlikely to be widely accepted by SA growers in the highly stressed low to medium rainfall areas in which it is suited.
Guardian, released by Longreach Plant Breeders in 2006, and eligible for the APW grade, has now been widely evaluated over three seasons in SA. In 2007 and 2008 trials it has performed particularly well in South East and Mid North trials, clearly favouring medium to higher rainfall environments where it shows a high yield potential albeit with some susceptibility to black point. While it has CCN and good stem rust resistance, it is rated moderately susceptible to stripe and leaf rust and susceptible to yellow spot. Grain from 2008 trials showed Guardian has good test weights like Yitpi, but produced much higher screenings in many test environments.
Evaluated in SARDI and NVT trials since 2004, Young has shown high yield in short and dry seasons in SA, through its very early maturity. Again in 2008, Young performed well in the Mallee and Upper Eyre Peninsula sites but trailed well behind others in districts like Yorke Peninsula. Young is eligible for the AH grade and combines CCN resistance with good yellow spot and moderate rust resistance making it an option for wheat on wheat rotations. However it has demonstrated small grain and relatively high grain screenings, in sharp finishing environments, and again in 2008, which should see it limited to only the longer season districts in South Australia.
Three new early to mid season, AH quality varieties, Catalina, Derrimut and Peake averaged 6 percent below Axe overall in trials. While this group originate from the former Victorian based wheat breeding program, Catalina was released by Longreach breeders and Derrimut and Peake by Nuseed breeders.
In 2008, Catalina performed relatively better than had done in the previous two years, generally out-yielding Yitpi at most sites but favouring medium to higher rainfall areas. Catalina has CCN resistance and good resistance to a range of foliar diseases including all rusts. Across all sites in 2008 it also produced acceptable grain quality with screenings slighty inferior to the levels of Yitpi but test weights generally well above. These characteristics should ensure Catalina has a fit in SA albeit with generally moderate grain yield.
The second ranked variety in 2007 trials, Peake, dropped back slightly in 2008 and produced a variable performance across environments. It had previously yielded well at Mallee sites but was moderated in 2008. Peake, also eligible for the AH grade, is early flowering and features acceptable to good resistance to all rusts, combined with CCN resistance and low susceptibility to yellow spot and septoria tritici. Grain from 2008 trials showed Peake has good test weights like Yitpi, but with much higher screenings in many environments, its acceptance among growers may be limited.
Averaging 2 to 3 percent above Yitpi respectively in 2008, were the AH quality, CCN resistant varieties, Correll and Derrimut. In a performance not unlike the previous year, Derrimut generally outyielded Yitpi in most district trials except Upper Eyre Peninsula. This variety, eligible for the AH grade, was released by Nuseed in 2006, has been widely evaluated across four seasons and shows some potential for medium to higher rainfall situations. It has short straw, boron tolerance, CCN resistance and good resistance to stem and leaf rust but is rated moderately susceptible to new stripe rust strains. As seen in other years, Derrimut generally aligns with Janz in receival quality, showing similar levels of screenings and susceptibility to black point but higher test weight.
Correll, released by AGT as an alternative to Yitpi with stem rust resistance produced a more moderate performance in 2008 relative to previous years. While derived from, and much like Yitpi, it is earlier flowering and moreso when sown early, an advantage in recent seasons. In 2008 and in previous seasons, Correll performed well across Mallee sites, but elsewhere yields were similar to Yitpi. While it has CCN and acceptable rust resistance, Correll, like Yitpi, is quite susceptible to yellow spot. Much like Gladius, Correll has also shown a lower tolerance to Ally® within herbicide tolerance trials. Its grain has improved black point tolerance relative to Yitpi, but continues to produce significantly lower test weight (2-3 kg/hl) and slightly higher screenings.
DURUMS
The 2008 season was again trying for durums which do not tolerate hot winds and dry conditions before and after flowering. Among the durums tested in 11 trials throughout South Australia, the two new recent releases from AGT, Saintly and Hyperno averaged 6 and 4 percent above Kalka respectively. The widely grown variety, Tamaroi was 5 percent behind Kalka
Saintly is the earliest flowering of these varieties, an advantage under the conditions experienced and Saintly has previously performed well in dry finishing conditions. Saintly is also awnless, a feature which may be useful when crops are cut for hay due to frosting or other adverse seasonal conditions. Alternatively, Hyperno which offers improved rust resistance and later flowering may be more suited to the higher rainfall durum districts of SA. Further evaluation of these varieties under better conditions will determine their fit across SA.
Together with several new high yielding varieties also being released from the Waite durum breeding program, the 2008 results signal a new era for durums in South Australia with new varieties offering improved yields, semolina quality and disease resistance.
