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Chapter four. breeding oats for irrigation in Australia

Glen Innes, on the New England Tablelands in NSW, has proven to be the best centre for breeding oats for the heavy soils of the Riverina at Leeton, southwestern NSW. Plant selections made on the black self-mulching soils of the Glen Innes Research Station of northern NSW have resulted in the varieties Acacia, Bundy, and Mugga; all now replaced by Blackbutt. Both areas require resistance or tolerance to stem rust, water logging, red-legged earth mites, BYDV, lodging, shattering and second growth. Although frost damage is less of a problem in the irrigation areas than on the northern tablelands of NSW, the frost resistant bulks from the cross F.Ga x VRAF.VRSF demonstrated good tolerance to water logging on heavy soils. Blackbutt also excelled as both a dual-purpose and a grain only variety, therefore a triple-purpose variety, and has been recommended for both northern and southern irrigation areas.

Introduction

In order to succeed in plant breeding for irrigation, it is necessary to study yields both in dryland and in irrigation trials, so that we can learn more about the complexities of yield itself, the different environments and requirements of the farmer. Non-irrigated as well as irrigated trials are therefore both considered relevant in this chapter. Alternative crop studies are also necessary.

Oats are regarded as needing more water to produce a unit of dry matter than any other small grain cereal except rice (Coffman 1961). Rice is the most important irrigated crop in the Riverine Plain of NSW. Wheat, however, is also extensively grown under irrigation but is very prone to crop failure if the varieity is susceptible to rust diseases (Leigh and Noble, 1972).

Oats is less affected by rust diseases and soil-borne pathogens than wheat and therefore, often resulting in higher yields under irrigation.

Oats can utilise more water than any other cereal except rice (Coffman, 1961) and is less prone to crop failure than wheat in the event of serious rust disease and the soil-borne pathogens which affect wheat and barley (Leigh and Noble, 1972). This is especially important in countries like Australia and China, where reliable sources of irrigation water are available and sometimes under-utilised, because of a need to apply a soil-conditioner like gypsum (Davidson and Quirk, 1961).

Yields of oats in NSW are compared with other cereals in Table 4.1.These statistics suggest that oats respond well under irrigation, however, this has only been the case since the 1980s. The results of trials presented in this chapter show the response of a range of oat cultivars, including the High-vigour varieties described in Chapter Three, as well as other cereals in the Riverine Plains of NSW.

Table 4.1 NSW cereal crop yields under dryland and irrigation (t/ha)a.

Years

Total

Irrigation Onlyb

Wheat

Oats

Barley

Wheat

Oats

Barley

1930-1939

0.93

0.72

0.98

0.82

0.63

0.84

1970-1979

1.43

1.06

1.24

1.43

0.92

1.18

1982-1990

1.60

1.24

1.49

1.52

1.33

1.27

a Data from Fitzsimmons (1990). b This data was taken from Leeton, NSW.

Australian research on irrigated oats and forage production

Australian research over the past 20 years has demonstrated the significant role oats have to play in irrigated farming and forage production.

Dann et al. (1983) have shown that Winglen, Windebri and Isis winter wheats produce significantly less early fodder than oats. Blackbutt oats out-yielded Isis wheat in grain yield by 125% in 1976 but the seed shattered badly in 1977. Severe grazing (down to 2 cm) never reduced the number of spikes or panicles per unit area of the Blackbutt variety. One disadvantage of oats in general is a tendency to shatter when ripe. To reduce shattering loss, oats can be windrowed up to 14 days before it can be direct headed.

Duncan (1983) found that triticale and rye both run to head early in the spring, producing a spiky head with the same disadvantages as barley. He also found that Blackbutt and Acacia oats (both bred at Glen Innes) were more resistant to waterlogging than Cooba, which was also less tolerant to heavy frosts than Blackbutt and Carbeen. Duncan found that oats were the most popular fodder crop for filling the winter feed gap and also served as a useful “clean-up” crop in weedy areas, after pasture improvement, because pastures are not competitive enough to keep out thistles, barley grass and burrs.

Muldoon (1986) has made a deep study of irrigated winter cereals and compared oats, barley, wheat, cereal rye and triticale under irrigation at Trangie in 1978 and 1980. Dry matter accumulation was described by mathematical equations which allowed cultivars to be compared under different cutting regimes. Muldoon (1986) also allowed dry matter and digestible dry matter yields to be predicted for irrigated cereals in western NSW. He showed that early maturing barley and triticale cultivars had lower digestibilities than oats. Oats and wheat had similar digestibilities and these began to decrease rapidly 40-50 days before head emergence (mid-August). Blackbutt oats had the highest cumulative regrowth of any winter cereal. Regular cutting (a total of 4 cuts) maintained the nitrogen content and digestibility of all cultivars above 2.7% and 72% respectively (Muldoon 1986).

Simmons (1987) noted that varieties with more prostrate growth withstand close grazing, trampling and heavy frosts better than more upright growers. Blackbutt was outstanding in this respect, although not as frost hardy as some winter wheats. Mugga oats also had greater frost resistance than Blackbutt but was not as productive in grazing as Blackbutt.

Powell (2000) found that Blackbutt oats sown as late as 1st April 1999 and harvested on 22nd December, yielded significantly more grain after 2 grazings than Nile and Eurabbie oats, Maiden Triticale, Tennant and all other wheat varieties. This followed grazing cuts on 11th June and 20th August, giving no significant differences, in the relatively dry, frosty winter at Gunning, on the Southern Tablelands of NSW. Eurabbie is a semi-dwarf oat, obviously not satisfactory for grain recovery yields after severe grazing.

Hubbell et al. (2000) in America found similar weight gains in 225 kg steers grazing winter wheat (1.25 kg/day), oat forage (1.34 kg/day), rye (1.25 kg/day) and perennial ryegrass (1.18 kg /day). McRae (2003) found similar results for Australia: Quality tests on the forage value of oats, wheat, barley, cereal rye and triticale, when grown under similar conditions, show no significant differences in protein, energy and digestibility. For overall forage production, however, he found that oats produce more than wheat, barley, cereal rye or triticale.

Dove (2004) found great variability in observed liveweight gains of animals grazing winter wheat, suggesting that more attention should be paid to cereal stage of growth and more accurate livestock comparisons and needs.

Testing of high-vigour varieties

The NSW Department of Agriculture has conducted dual-purpose and grain only oat trials for many years in the Riverine Plain of NSW, a major irrigation area. The early varieties, P4315, Avon, Cooba and Coolabah were compared with the late varieties, Blackbutt, Acacia, Algerian, Klein 69B and Mugga over the period of 1963 – 1973 (Table 4.2). The varieties were kept in 2 separate groups, for ease of harvesting. The mid-season variety Bundy was common to both early and late trials. Due to the frequent tendency of Avon to make second growth and to delay harvest, early varieties sometimes were over-ripe and suffered some shattering losses as a result. Grazing yields are not given in these trials as they are usually too lenient in character to assess grazing potential under irrigation.

The High-vigour bulk, P4315, topped the yields both in the grain only and in the grain recovery after grazing trials (Table 4.2). Similarly, Table 4.3 compares only grain recovery (grazing yields excluded) with grain yields on dryland in the Riverina. P4315 tops both sections without irrigation. This line therefore demonstrates a triple-purpose capacity, that is, high dual-purpose and high grain only yields. Blackbutt, under irrigation showed the same capacity but the earlier compounded bulk, P4315, was more adaptable, being triple-purpose under both irrigation and dryland conditions (Tables 4.2 and 4.3).

Irrigation does not always give the highest yields unless the season is dry and drainage is good. The research plots at Cowra (results presented in Table 3.7, Chapter Three) were not irrigated and yet out-yielded the irrigated trial at Coleambally, NSW (Table 4.4). In this trial at Colleambally in 1985, Blackbutt demonstrated its high grain yield potential. The comparison between the irrigated site at Coleambally with the dryland trial at Adelong, showed the superior grain recovery yield of Blackbutt over those of wheat, barley and rye. In the very cool climate of Adelong NSW, the Tasmanian oat variety, Nile, was significantly the highest yielder of all the crops and varieties tested.

More recently, Sydney University's rust resistant Algerian-derived cultivar, Sual, has given high yields under irrigation although the straw is tall and weak, which requires this variety to be grazed (data not presented). This is impossible if water-logging occurs.

The semi-dwarf variety, Eurabbie, released in 1998, is too short after heavy, late grazing. This results in harvesting difficulties. Eurabbie is also susceptible to rusts and BYDV, making it unsuitable for irrigation (McRae et al. 2004).

Avon, a high yielding grain oat from West Australia, was found to be unsuitable for growing in irrigation areas because of its tendency to remain green for too long, holding back harvest operations.

Most virgin soils of the Riverine Plain have extremely low infiltration rates (Leigh and Noble, 1972). Gypsum has made possible successful pasture establishment (Davidson and Quirk, 1961). On these soils, pasture establishment and rotation provide a sound basis for arable cropping. Due to the original nature of these soils, they still require oat varieties resistant to occasional waterlogging. For this reason, selected varieties at Glen Innes including Bundy, Acacia, Mugga (Guerin, 1966) and the High-vigour bulks have demonstrated their tolerance to these conditions, as have Klein 69B, Coolabah and Cassia (Fitzsimmons, 1986). The latter three should not be considered for grazing here in the Riverine Plain, because of poor quality grains per se. Resistance to summer storms at Glen Innes is also useful for selecting varieties for growing under irrigation.

In the grain only trial, the dual-purpose cultivar bred in northern NSW, Blackbutt, yielded over 5 t/ha at Coleambally. Blackbutt outyielded all the specialised grain only oat varieties from West Australia, South Australia and Victoria (Figure 4.1). This triple purpose capacity was displayed by Blackbutt, due to its strong straw or general resistance to lodging, derived from the wide diameter culms of Garry (one of its parents). The trial at Colleambally included the dwarf oat Echidna, which appeared to lack drought resistance in the dryland trial site at Adelong, NSW (notwithstanding the cool climate). Coleambally and Adelong yields are compared in Figure 4.1. The Glen Innes bred cultivars Bundy, Mugga, Acacia, Carbeen and Blackbutt have been high-yielding under irrigation. This appears to be associated with their resistance to water-logging at Glen Innes, where drainage is sometimes impeded on the black basaltic soils, otherwise soils of high fertility, especially in dry seasons.

The strong straw of Blackbutt as well as its moderate resistance to BYDV and some strains of stem rust made it suitable for irrigation (Verrell and Gammie, 1992). Oats in general do not have the same disease problems as other cereals. The most serious diseases of oats are leaf (crown) rust, bacterial leaf stripe, BYDV and the head smuts, to the last three of which Blackbutt is tolerant or resistant to these final three diseases.

Recommendations for oat breeding programs

Oat breeding for irrigation should consider the following. Firstly, resistance to waterlogging especially in heavy soils. Acacia x Lampton lines bred by Carroll at Glen Innes were outstanding in this respect in the 1960s. Secondly, the strong straw of the High-vigour lines from F.Ga x VRAF.VRSF, namely Blackbutt and P4315, seems to derive from the tall strong-strawed variety, Garry (Ga). The shorter culms of P4315, for instance, had thicker stronger walls than those of Cooba, a variety without Garry parentage. It is for this reason that Cooba is not suitable for grain only, especially under irrigation. Finally, a separate point is the harvest index, or grain-hay ratios. Yield improvements to Ballidu, Orient and Avon have been attributed solely to an increase in harvest index (Sims, 1963). Results reported at the Adelaide conference (Guerin and Guerin, 1992) suggest that 1309 has a higher harvest index than Cooba with a hay yield equal to that of Cooba. Both Cooba and 1309, sister lines of the same cross, VRAF.VRSF, have high quality grain and good milling characteristics, therefore 1309, the parent of the High-vigour, is a better choice for crossing, or back-crossing, than Cooba, which is moreover lower in frost resistance. The grain/hay ratios reported (Guerin and Guerin, 1992) demonstrates that the High-vigour line, 856 G59 (P4314) has the highest harvest index recorded and yet is significantly higher in hay yields to both Cooba and 1309. This high harvest index appears to be derived from Fulghum.

Table 4.2 Comparisons of early and late maturing cultivars under Irrigation in the Riverina for a 10 year period for grain only (G), and grain recovery (pG) (1963-1973).

Cultivars
(Inventory Number)

G (mean of 7 trials)
(t/ha)

pG (mean of 4 trials)
(t/ha)

P4315 (38)a
Coolabah (105)a
Cooba (22)a
Bundy (15)a
Avon (101)a

Blackbutt (11)
Bundy (15)
Mugga (58)
Coolabah (105)
Cooba (22)
Klein 69B (53)
Acacia (1)
Algerian (70)

3.76
3.61
3.42
3.36
3.30

4.36b
4.00b
3.79b
3.57b
3.23b
-
-
-

2.88
2.40
2.06
2.54
-

3.26c
2.75c
2.22c
-
-
2.21c
2.06c
2.03c

Trials were conducted in the Murrumbidgee Irrigation Area, NSW, under irrigation from 1963-73; a early maturing cultivars; b late maturing cultivars, 2 trials; c late maturing cultivars, 4 trials.

Table 4.3 Comparisons of grain only (G) yields and grain recovery (pG) in the Dryland Riverina for a 10 year period (1963-1973).

Cultivars
(Inventory Number)

G (mean of 9 trials)
(t/ha)

pG (mean of 4 trials)
(t/ha)

P4315 (38)
Cooba (22)
Avon (101)
Coolabah (105)
Bundy (15)a

2.03
1.90
1.88
1.80
1.71

1.59
1.47
1.55
1.32
1.38

a The low yields of Bundy (Guerin, 1965), a drought tolerant variety, suggests an abundance of soil moisture in these trials, with P4315 exhibiting a triple-purpose capacity.

Table 4.4 Year 24 of testing Blackbutt oats under irrigation versus dryland (1985): F29 generation trial.

Cultivar
(Inventory Number)

Irrigation sitea
Gc (t/ha)

Cool dryland siteb
pGd (t/ha)

Blackbutt (47)
Cassia (103)
Hakea (109)
Echidna 206)
Dolphin (205)
Bundalong (204)
Barmah (202)
Nile (209)
Carbeen (41)
Cooba (22)
Yarran (114)
Coolabah (105)
Mortlock (208)
Bulban (203)
West (214)
Rysun, rye
Malebo, barley
Quarrion, wheat
Rosella, wheat
Osprey, wheat
Forrest, barley
SD
CV (%)
Date of sowing
Date of harvest

5.29
4.89
4.78
4.76
4.63
4.36
4.25
4.05
3.75
3.61
3.02
2.89
2.89
2.71
2.62
-
-
-
-
-
-
n.a.
-
11.4.85
18.12.85

2.40
-
-
1.58
-
-
-
2.85
2.31
2.01
2.12
1.90
2.00
-
-
1.94
1.94
1.77
1.66
1.35
1.22
0.44
13.6
26.3.85
21.12.85

a Coleambally NSW trial, lodging prevalent; b Adelong NSW; c Grain only trial; d Grain recovery after grazing, which was not measured by a pasture cut; n.a. = not analysed.

Figure 4.1 A diagrammatic comparison of eight cultivars under irrigation (grain only) and cool dryland (grain recovery) in t/ha (Colleambally, NSW in 1985).

Conclusions

Glen Innes, on the New England Tablelands in NSW, has proven to be the best centre for breeding oats for the heavy soils of the Riverina in southwestern NSW. Plant selections made on the black self-mulching soils of the Glen Innes Research Station of northern NSW have resulted in the varieties Acacia, Bundy, and Mugga; all now replaced by Blackbutt. Both the Riverina and northen NSW require resistance or tolerance to stem rust, water logging, red-legged earth mites, BYDV, lodging, shattering and second growth. Although frost damage is less of a problem in the irrigation areas than on the northern tablelands of NSW, the frost resistant bulks from the cross F.Ga x VRAF.VRSF demonstrated good tolerance to water logging on heavy soils. Blackbutt also excelled as both a dual-purpose and a grain only variety, therefore a triple-purpose variety, and has been recommended for both northern and southern irrigation areas.

In summary, the key characteristics required for breeding a successful oat variety for irrigation, in addition to stem rust, BYDV, and insect resistance, are (A) resistance to water logging, (B) strong straw and (C) a high harvest index.

References

Coffman, F.A. 1961. Oats and Oat Improvement. American Society of Agronomy.

Dann, P.R., A. Axelsen, B. S. Dear, E.R. Williams and C.B.H. Edwards. 1983. Australian Journal of Experimental Agriculture and Animal Husbandry 23: 154-161.

Davidson, J.L. and J.P. Quirk. 1961. The influence of dissolved gypsum on pasture establishment on irrigated sodic clays. Australian Journal of Agricultural Research 12: 100-110.

Dove, H. 2004. Grazing grains—Cereals in grazing systems. CSIRO, Canberra, ACT.

Duncan, M. 1983. Winter fodder crops: northern tablelands. Agdex 120/20, Agriculture NSW.

Fitzsimmons, R. 1986. Winter cereal variety performance 1985-6 Season. Agdex 110/34, Agriculture NSW.

Fitzsimmons, R.W. 1990. Winter cereal production statistics. Australian Institute of Agricultural Science. Occasional Publication No. 48.

Guerin, P.M. 1965. Bundy - The breeder's report: A new midseason oat variety for Northern NSW. Agricultural Gazette NSW 76: 667-669.

Guerin, P.M. 1966. Mugga - The breeder’s report. Agricultural Gazette NSW 77: 675-678.

Guerin, P.M. and T.F. Guerin. 1992. Breeding oats for irrigation in Australia. In Fourth International Oat Conference, Adelaide, Edited by A.R. Barr, R.G. McLean, J.D. Oates, G. Roberts, G. Rose, K. Saint, and S. Tasker, pp. 187 – 190.

Hubbell, D.S., Daniels, L.B., Harrison, K.F., Johnson, Z.B., Brown, A.H., Kegley, E.B., Coblentz, W.K. and Coffey, K.P. 2000. Arkansas Animal Science Department Report, pp.70-71.

Leigh, J.H. and J.C. Noble. 1972. Riverine Plain of NSW, its Pastoral and Irrigation development. CSIRO Division of Plant Industry, pp 1-63.

McRae, F.J. 2003. Crop agronomy and grazing management of winter cereals. GRDC Update.

McRae, F.J., D.W. McCaffery and D.J. Carpenter. 2004. Winter Crop Variety Sowing Guide, NSW Agriculture.

Muldoon, D.K. 1986. Dry matter accumulation and changes in forage quality during primary growth and three regrowths of irrigated winter cereals. Australian Journal of Experimental Agriculture and Animal Husbnadry 26, 1: 87-98.

Powell, C. NSW Agriculture, 2000: Winter Crop Variety Experiments for 1999.

Simmons, K. 1987. Oats. Agfact P3.2.2. Wagga Wagga, NSW Agriculture.

Sims, H.J. 1963. Changes in the hay production and the harvest index of Australian oat varieties. Australian Journal of Experimental Agriculture and Animal Husbandry 3, 10: 198-202 .

Verrell, A.G. and R.L. Gammie. 1992. Winter Cereal Variety Sowing Guide. NSW Agriculture.

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