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Prime quality high protein wheat variety evaluation in South Australia

H.A. Reimers1, M.Miyan1, G.Hollamby1, A.Rathjen2, R.Wheeler3

1Adelaide University, Roseworthy Campus, South Australia.
2Adelaide University, Waite Campus, Urrbrae, South Australia.
3 SARDI, Waite, Campus, Urrbrae, South Australia.

Abstract

Variety trials were conducted at 11 low rainfall sites in South Australia over a five year period, commencing in 1995. The performance of recognised Prime Hard varieties was compared with that of high quality southern varieties and breeders’ lines that were considered to be of potential Prime Hard quality. Grain produced in these trials was submitted to an extensive series of quality tests conducted in order to determine whether Prime quality standards were met and maintained. The southern breeders’ line RAC820 was found to be of Prime Hard quality and has now been released as the variety Kukri. The quality testing results indicated that Prime Hard quality, high protein wheat can be produced in the Upper Eyre Peninsula and Northern Murray Mallee of South Australia.

Key words

Wheat, protein, prime hard, prime quality, variety.

Introduction

Prime Hard wheat varieties are currently segregated in N.S.W and Qld, and growers in other states are prevented from receiving this classification even when their protein levels are well above the minimum standard for Prime Hard. It had previously been thought that even when protein levels are sufficient, other characteristics of the flour and dough would prevent southern wheat reaching Prime Hard standard. Following an extensive research program conducted by N.S.W. Agriculture, the area in which such wheat is received has recently been extended into southern N.S.W (1). The research reported in this paper was conducted over a five year period, commencing in 1995, to test the performance of existing varieties and breeders’ lines at a number of low rainfall sites where it was expected Prime Hard quality grain could be produced.

Methods

Between 1995 and 1999 replicated varietal trials were conducted to compare the performance of a number of Prime Hard varieties, high quality local varieties and promising breeders’ lines. The 11 sites on the Upper Eyre Peninsula and Northern Murray Mallee, (Table 1), were selected on the basis of a past history of delivery of high protein wheat. Each variety was evaluated in order to assess its yield potential and flour quality when compared with recognised Prime Hard varieties. An extensive series of flour, dough and baking testing was carried out at the Wagga Wagga quality laboratories. This testing procedure was chosen to allow comparisons with grain produced in NSW.

Table 1. Prime quality varietal testing sites.

The quality tests included: grain characteristics (test weight, 1000 grain weight, protein, hardness, moisture, flour extraction and flour colour index), physical dough testing (Farinograph and Extensograph), baking tests (mixing requirement, loaf volume and baking score) and yellow alkaline noodle testing (colour development, stability and starch pasting properties).

To complement this varietal testing program, a series of trials was run at three sites to develop agronomic management recommendations for the growing of prime quality high protein wheat. The results of these experiments are reported in another paper at this conference.

Results and Discussion

The yield and protein data for a number of potential and existing Prime Hard varieties are presented in Tables 2, 3 and 4 for sites at Kimba, Lock and Wunkar. These sites were chosen as typical examples that encompass the variation found across the two regions. The ASW variety Worrakatta was included in the last three years in order to provide yield comparison with Prime Hard quality material, as it is expected growers will need to allow for a yield penalty in estimating the profitability of growing Prime Hard varieties. Of the Prime Hard quality varieties, Janz had the highest yields over the five year period.

As can be seen from Table 2, Lock produced the desired protein levels in only three of the five years and so, along with Mitchelville, is considered to be a site which cannot be relied upon for the production of Prime quality high protein wheat.

Table 2. Prime Hard quality variety trials mean site yield (t/ha) and protein % (Lock)

Kimba was representative of the 6 Eyre Peninsula sites where Prime quality, high protein wheat, could be produced regularly. The data in Table 2, is given to demonstrate the degree of yield variation typical of the upper Eyre Peninsula and also illustrates the high levels of protein achievable. Excessive levels of protein (>16%) have been found to be undesirable in Prime Hard wheat (H. Allen, pers. comm.) and so nitrogen management practices will need to be carefully managed.

Table 3. Prime Hard quality variety trials mean site yield (t/ha) and protein % (Kimba)

Wunkar was representative of the 3 northern Murray Mallee sites which all had the capacity to produce Prime quality high protein wheat on a regular basis (Table 4). Protein levels in the northern Murray Mallee did not reach the extremely high levels found on the upper Eyre peninsula however there was large variation in yield from year to year. Such yield variations result from the amount and distribution of growing season rainfall. A typical example is shown if we compare 1996 and 1997 which had 249mm and 289 mm annual rainfall respectively. The April-October rainfall was 191mm (1996) and 150mm (1997) and yet the mean site yield in 1996 (0.81 t/ha) was approximately 1/3 less than that of 1996 (1.26 t/ha). Potential yield calculations would predict higher yields in 1996 (1.61 t/ha) than in 1997 (0.8 t/ha). Much of the difference could be attributed to the conservation of heavy summer rainfall and good finishing rains in 1997 compared to poor summer and spring rains in 1996.

Table 4. Prime Hard quality variety trials mean site yield (t/ha) and protein %. (Wunkar)

As can be seen from Table 5, grain size of Janz is generally lower that of Kukri which consistently produced higher protein levels (Tables 2, 3 & 4). The maintenance of adequate grain size is seen as one of the major impediments of Prime Hard quality production in the upper Eyre Peninsula and northern Murray Mallee. This desirable attribute needs to be addressed through management techniques such as early seeding, low N application rates, increased seeding rates and use of larger seeded varieties.

Table 5. Prime Hard quality variety trials site mean 1000 grain weight g

The extensive flour and dough quality testing program indicated the suitability of the grain for Prime Hard end use. In particular, the new variety Kukri was found to produce quality high protein Asian noodles with good colour stability. However this variety has very extensible dough and so requires increased mixing time if it is to provide a loaf volume comparable to that of the other varieties.

The variety trial results confirmed that wheat of the required minimum protein level and Prime Hard quality can be produced at all of the selected sites. However the sites at Lock and Mitchelville were less likely to reach the desired minimum protein levels. This result is consistent with the conclusions of Oliver. (pers. comm.) who compared the performance of wheat grown in southern Australia with that grown in three traditional Prime Hard areas of N.S.W.

Conclusions

In the low rainfall areas of the upper Eyre Peninsula and northern Murray Mallee in South Australia, the Prime Hard variety Janz was generally the highest yielding variety. However grain size for Janz fell below the desired minimum level on a number of occasions. In addition this variety usually was lower in protein than the other varieties tested.

The early variety Kukri, (tested as RAC820 in these experiments), is large grained, has very extensible dough, and is well suited to the production of high protein Asian noodles. This variety was released in 1999 as the first South Australian bred variety of Prime Hard quality.

The midseason variety Chara, (tested as VI341), has also been released from the Horsham program as a potential Prime Hard quality wheat.

Prime Hard quality wheat can be produced regularly in the low rainfall cereal belt of South Australia but will require a separate segregation for which a premium price is paid to growers to offset yield penalties incurred in comparison with Australian hard wheats such as Yitpi.

Acknowledgements

This research was supported by the GRDC and all quality testing was undertaken under the direction of John Oliver and Helen Allen of NSW Agriculture at Wagga Wagga.

References

Allen, H., (ed.) undated. Australian Prime Hard Wheat in South-Eastern Australia …a growers guide. NSW Agriculture, Wagga Wagga.

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