The Regional Institute - The New Generation Of Pasture Legume Varieties And Species

THE NEW GENERATION OF PASTURE LEGUME VARIETIES AND SPECIES

B.S. Dear

Senior Research Agronomist, NSW Department Of Agriculture
Agricultural Research Institute. Wagga Wagga. 2650.

Introduction

Over the last 10 years there have been relatively few new annual pasture varieties or species released making it easy for farmers to choose which variety to sow when re-establishing pastures.

This situation has, however, already changed with the number of new varieties and species increasing dramatically over the last few years and there is promise of many new releases over the next 5 years.

The significance of this change is that farmers will now have to completely reappraise the varieties they normally sow to determine if they are still the most suitable or if they should be replaced. As many of the new pasture plants have never been commercially grown in the region, farmers will need to refer to experimental results to obtain the most up-to-date information.

Not all the new varieties will be suited to every farming enterprise and it will be lust as important to weed out the unsuitable varieties as it is to select new highly productive varieties.

How can pasture legumes be improved?

Legumes play a crucial role in determining the carrying capacity of a pasture. The higher the legume content, the higher is the quality of the feed and the greater the intake and digestibility by the animal, leading to higher liveweight gain and wool production. Therefore in choosing the best variety, the goal is to firstly improve PERSISTENCE of the legume to ensure the highest proportion of legume in the pasture over time. This is best done by looking for hardseed and the correct maturity in new varieties.

The second step is to extend the GROWING PERIOD of the legumes in the pasture which is most easily done by extending growth in late spring, early summer. This should be done carefully as extending the growing period too far may reduce seed set and persistence. The best method of achieving a greater spread in production is to sow mixtures of cultivars and species which vary in their maturity.

Finally, varieties with the greatest INSECT and PEST RESISTANCE should be chosen.

Following is a summary of recently released new species and varieties and those which are expected within the next three years.

New Species And Varieties

Subterranean Clover

Subclover is the mainstay of the pastoral system in southern New South Wales and Victoria. However, in recent times the advent of acid soils, root rots and more intensive cropping has resulted in a decline in the quality of subclover-based pastures. This is therefore the ideal opportunity to re-establish new improved varieties.

A national breeding programme supported by funds from the Australian Wool

Research Development Fund has produced a number of well proven, new

varieties with even better varieties in the pipeline for release in about

3 years.

(a) Recently released varieties Dalkeith -

This low oestrogen variety has the highest level of hardseed of all subclover varieties. It is slightly later maturing than Nungarin but earlier flowering than Daliak. It is therefore ideally adapted to country normally supporting the oestrogenic variety Dwalganup. Dalkeith not only produces a high proportion of hardseed, it also buries a large proportion of the seed which makes it very tolerant of heavy grazing, poor seasons and false breaks. Being slightly later maturing than the early maturing varieties Nungarin and Northam it is more productive than these two varieties in late spring. It is recommended for the wetter regions of the Nungarin zone or for use in mixtures with Nungarin or Daliak.

Its high level of hardseed will not only give improved plant densities, but should also ensure better regeneration following a short cropping phase.

It should not be grown in higher rainfall areas (greater than 475 mm) where it will mature too early, unless it is being grown as a companion to lucerne.

Junee -Although Woogenellup has been the most popular variety in the medium rainfall

areas of the State (500-700 mm) the occurrence of severe outbreaks of tap root rot (Phytophthora clandestina) in irrigation areas and more recently in dryland areas has seen the performance of this variety decline dramatically. Its low level of hardseed has also resulted in erratic performance particularly where false breaks to the start of the season are common.

Trikkala has now replaced Woogenellup in irrigation areas where Trikkala’s excellent root rot tolerance has been well suited. However, it has a very low level of hardseed which has not suited it to many dryland situations. As a result the variety Junee has been released specifically for the drier areas (500-600 mm rainfall) of the Woogenellup zone.

Woogenellup is still recommended as part of a mixture for the higher rainfall areas (600-650 mm) or for short term pastures.

Junee has greatly improved tolerance of root rot and higher levels of hardseed giving it higher resistance to false breaks. Its perforamnce in district trials has been superior to Woogenellup where either root rot or false breaks occur. Junee is not as “showy” in its growth habit as Woogenellup but measurements have shown that winter and early spring yield is equal to or greater than that of Woogenellup.

Karridale -

Mount Barker has been grown extensively in the higher rainfall areas of the slopes and tablelands. However, after widespread testing, a new variety called Karridale has been released with at least equal performance and in many cases superior growth. The hardseed level has been increased slightly, it is also later maturing making it ideal for areas experiencing good late spring rainfall. Karridale has superior tolerance to red-legged earthmite than Mount Barker which is important given the increasing prevalence of this pest in recent years. Karridale should be grown in areas receiving at least 650 mm rainfall to ensure long term persistence.

The characteristics of these new subclover varieties is compared with existing varieties in Table 1.

Table 1. Characteristics of currently recommended subclover varieties

Variety	Days to Flowering	Minimum Rainfall Reqt.	Maturity Class	Hays off
NUNGARIN	133	375 mm	Very early	Early October
DALKEITH	140	400 mm	Very early	Mid October
DALIAK	161	450 mm	Early	Late October
SEATON PARK	165	475 mm	Early mid	Early November
JUNEE	174	500 mm	Mid season	Late November
TRIKKALA*	168	500 mm	Mid season	Early December
WOOGENELLUP	176	525 mm	Mid season	Early December
MOUNT BARKER	181	650 mm	Mid late	Mid December
KARRIDALE	183	650 mm	Mid late	Mid December

* Based on May 26 germination

Enfield and Green Range -

These two recently released varieties are not recommended for New South Wales, although they have proven successful elsewhere. En field is very softseeded and while suited to very reliable environments in southern Victoria does not perform well under more variable rainfall conditions. Similarly the recently released Green Range which was intended as a Woogenellup replacement has proven very susceptible to leaf rust and is therefore not recommended. Although leaf rust is not frequently seen in New South Wales, most of our varieties are relatively tolerant and the sowing of a susceptible variety could see this disease become widespread.

(b) Subterranean Clover - cultivars in the pipeline

The National Subclover Improvement Programme Supported by the Australian Wool Research Development Fund is well advanced towards the goal of releasing further new varieties within the next 5 years.

Variety A - Woogenellup replacement

This mid-season variety will have similar vigour and growth habit to Woogenellup but higher levels of hard- seed, good resistance to clover scorch and root rot. It is later maturing than Junee and more suitable for hay production.

Variety B - A Mount Barker Replacement

A late variety with high levels of clover scorch resistance, root rot tolerant, more hardseed and later maturing than Variety A.

Variety C - Seaton Park Replacement

An early-mid season variety with superior clover scorch tolerance, hardseed and root rot tolerance.

Variety D - A hardseeded replacement for Trikkala and Yarloop. Suitable for waterlogged or poorly drained situations with good clover scorch resistance.

Barrel Medics (Medicago truncatula)

Jemalong barrel medic was widely grown on the neutral to alkaline soils until the advent of spotted alfalfa aphids (SAA) and blue green aphids (BGA). Jemalong proved very susceptible to these aphids and subsequently was replaced by two new aphid tolerant varieties.

Paraggio

The variety Paraggio became commercially available in 1984 and is tolerant of both SAA and BGA. This variety is now recommended for southern New South Wales areas receiving as little as 400 mm annual rainfall, and 500 mm rainfall in central and northern parts of the State. Paraggio has a similar maturity to Jemalong but improved second year regeneration, better seedling vigour and more tolerance to insect pests.

Sephi

A second variety called Sephi became available in 1985 and has excellent tolerance to both SAA and BOA and has performed better than Jernalong and Paraggio in central and northern New South Wales. Sephi has a more vigorous seedling than either Jemalong or Paraggio.

Parabinga

Another new barrel medic is the cultivar Parabinga which was released by South Australia as an interim Harbinger replacement. This cultivar is adapted to the driest parts of the medic zone (275 mm annual rainfall). It is early maturing, tolerant of both SAA and BOA and adapted to light textured soils. At this stage it is provisionally recommended for trial sowings in New South Wales. It should be used in mixtures with Sephi and Harbinger.

An aphid resistant Jemalong cultivar is currently in the breeding stage and could be released about 1991. In the meantime Paraggio is the most suitable alternative.

Snail Medic (M. scutellata) Sava

Work is currently in progress to breed an aphid resistant Harbinger variety. These medics are suited to self-mulching alkaline soils in the drier areas of the State (400 mm annual rainfall). The variety Sava is resistant to SAA and tolerant of RCA but regeneration from seed can be very variable.

Gama Medic (M. rugosa)

Varieties available include Paraponto, Sapo and Paragosa.

A large quantity of seed of these medics is now being produced in South

Australia. These medics are known to have a role on alkaline soils in

South Australia, however are not recommended for growing in New South

Wales.

Strand Medic (M. littoralis)

Trials by Rick Young on the mallee soils of southern New South Wales have shown that Harbinger strand medic is superior to barrel medic although it is extremely susceptible to both SAA and RCA; as a result it is suggested that equal mixtures of Harbinger and aphid-resistant barrel medics be sown on the mallee soils.

Further enquiries on the above medics should be directed to Rick Young at the Condobolin Research Station.

Murex (M. murex)

Medics have been traditionally grown on the more alkaline soils bt this is about to change with the release of a new medic species in 1988-89. Due to a breakthrough in the development of a new acid soil-tolerant Rhyzobium, Medicago murex will grow well on mildly acid soils. Murex has several advantages over subclover which warrant its sowing either in mixtures or by itself. It has hardseed levels three times greater than subclover varieties of similar maturity (Seaton Park and Woogenellup) making it ideally suited to resist false seasonal breaks. Trials in Western Australia have also shown superior sheep liveweight gain when grazed on murex compared to subclover.

This is thought to be due to delayed maturity by murex giving better liveweight performance over summer. Regeneration by murex at Temora has been excellent over a 3 year period despite its high levels of hardseed.

It has an upright growth habit and good resistance to moisture stress making it ideally suited to hay production. Its stems are thicker than subclover and consequently residues do not degrade as fast over summer compared to subclover leaving more dry feed available.

At present it is thought that this species will be confined to slightly acid soils in the 500+ mm rainfall zone and will not be recommended for the drier medic areas.

A new murex inoculant will be marketed as without this inoculant murex will not grow effectively. The new murex cultivar, yet to be officially named, has a growing period similar to Woogenellup and can set up to 1000kgseed/ha. The seed is contained in relatively smooth pods which should not prove to be a wool contaminant. Seed of the new variety will be commercially available in 1989.

Serradella (Ornithopus spp)

Although serradella is best known for its ability to grow on deep acid sands, it can also be grown on heavier acid soils. It is very deep rooting which contributes to its good drought tolerance on sandy soils and ridges. Although it is tolerant of heavy grazing, it should be grazed more leniently during flowering. Serradella is more productive than subclover on very acid soils with high levels of aluminium. Subclover is more productive where acidity is not high, on shallow or waterlogged soils.

Serradella is most suited to country receiving between 450 and 700 mm annual rainfall. Until recently two varieties of yellow serradella have been grown, Pitman and Uniserra, but both of these varieties are about to be replaced by superior varieties.

Tauro

The first new variety released, called Tauro, will become available in 1988. This variety replaces Uniserra and is suited to the 450-500 mm rainfall zone. It will be released by the West Australian Department of Agriculture and is said to have good winter production.

GS046 .1

The second variety to be released is codenamed GS046.1 and will be recommended as a Pitman replacement for wetter areas than Tauro, being suited to the 500+ mm rainfall areas. GS046.1 has superior tolerance to high aluminium levels than both of the older varieties. It will not be commercially available until 1988.

Because of its very high level of hardseed a few practices must be followed to achieve good establishment. Seed purchased should be heat treated prior to sale to increase the level of germinable seed. Seed should be inoculated with special inoculant (Group G). Serradella is said to establish well under a lupin crop. As lupins use the same inoculant it is only necessary to inoculate the lupins. A sowing rate of 5-10 kg/ha is recommended with seed costing about $4.00/kg. If the sowing rate is reduced, it can take up to 3 years to thicken if initial establishment is poor. The use of a lupin cover crop may allow lower serradella sowing rates to be used and lessen the cost of establishment.

As seed certification regulations vary from State to State some serradella seed produced interstate can contain various weeds and care should be taken to ascertain any impurities in the seed and the germination count. Further enquiries on serradella should be referred to Tim Drew at Trangie Research Station or Bob Freebairn at Goonabarabran.

Persian Clover (Trufolium resupinatum)

Persian clover is a highly productive legume which is distinctive by virtue of its extremely high digestibility compared to other pasture plants. As a result it produces excellent livestock production (meat/milk) and makes a very high quality fodder or hay. It can grow very tall when ungrazed. Being relatively late maturing it requires a rainfall of at least 550 mm or can be grown under irrigation. The major drawback of persian clover is that the only variety available until this year, Maral, has no hardseed and was late flowering (December). As a result it did not regenerate well and had to be resown each year. Maral has therefore only been suitable as a one year forage/hay crop.

A new variety has been registered this year in South Australia, codenamed SA 18920 which should become commercially available in 1988. This variety has two major improvements over Maral which significantly improve regeneration. Most importantly, the hardseed level has been increased from zero up to over 80% to give a better carryover of seed. Secondly, the flowering date has been advanced by three to four weeks which will allow seed set to occur in more favourable conditions. This new variety was sown in 1987 experimentally for the first time in New South Wales to evaluate its potential to regenerate. Its performance is therefore unknown, however experience in South Australia has suggested it can regenerate strongly and is a significant improvement on Maral. The older variety Maral is still useful as a late maturing irrigation type. A special new inoculant for persian clover became available in 1987 which should be used for all new sowings.

Balansa Clover (Tritolium balansae)

This clover is creating a significant amount of interest as there are large supplies of seed available at relatively low prices.

Only one variety is available, called Paradana. It has an extremely small seed which must be sown very shallow, only I to 3 kg/ha is required. If sown late (May) or where there is a late break in the season, growth is very slow until August when there is a rapid surge. Regeneration of this species is excellent due to its ability to set a large amount of seed with a high proporti6n of hard seed. It may be sown early (March) as a special purpose pasture under irrigation and will provide good grazing over autumn or sown later as part of a mixture with subclover.

It can grow up to 1 metre high and has the potential to grow up through wheat crops. This should not be a problem as most crops are sown relatively late which will kill any early established balansa and it could be easily controlled with a broadleaf herbicide.

It is very tolerant of waterlogging, has no oestrogens and is extremely tolerant of clover scorch. It is said to be tolerant of acid soils but grows poorly on alkaline or sandy soils.

When establishing balansa it is important to control red-legged earthmites in seedling stands. Balansa clover requires at least 500 mm annual rainfall, flowering about the same time as Seaton Park subclover.

Breeding of new improved strains is in progress in South Australia with the object of producing early flowering cultivars for drier areas.

In trials in Victoria and South Australia it has out-yielded subclover. It uses the same inoculant (Group G) as subclover.

Berseem Clover (Trifolium alexandrinum)

This annual species has not been thoroughly evaluated in New South Wales but is recommended for trial sowings in coastal river valleys and in some higher rainfall areas. It has been traditionally grown on heavy alluvial soils but will tolerate a wide range of soils.

Its popularity arises from its ability to grow on heavy soils that remain wet over winter when it can produce more feed than ryegrass, clover or oats.

It requires an annual rainfall of at least 630 mm with a winter incidence. Carmel

Until recently, the only recommended variety available was Carmel (multicut). This variety did not regenerate well from seed and was very sensitive to frost.

Big B

Anew variety called Big B is available which is marketed by Wright

Stephenson. It is claimed to be frost tolerant and regenerates from seed.

However there is little local experience.

White Clover (Trifolium repens)

The variety Haifa has significantly increased the area over which white clover can grow and persist, its improved drought tolerance being its main advantage. Haifa is recommended for sowing in areas receiving at least 700 mm annual rainfall. It produces more winter feed than Grasslands Huia.

Grasslands Huia is recommended for high rainfall areas (more than 750 mm) and for high altitudes.

New Zealand has released three new cultivars of white clover, however these have not yet been evaluated for southern New South Wales.

Grasslands Pitau is said to be a very winter active type, best suited to grazing by cattle.

Grasslands Tahola is a dense, persistent, small leafed type suited to heavy grazing. It is said to be more productive under low phosphorus conditions than some other white clovers. This cultivar holds the most promise of the three new cultivars. Grasslands Kopu is a persistent Ladino type.

Seed Quality

There are basically three grades of seed that can be purchased.

(a) Certified seed

The highest quality of seed available, the label must specify the germination percentage and the presence of other plants including declared weeds. Care must still be taken to read the label carefully (see below).

(b) SIA seed

Seed in this category meets all the requirements of certified seed except that it may contain other varieties. It is still high quality seed, free of noxious weeds and as it is cheaper than certified seed is value buying and highly recommended providing contaminant varieties are non-oestrogenic.

Seed sold in this category may be of good quality but can contain a range of other varieties including unfavourable varieties and may contain weeds. The germination percentage can be very variable.

When buying all categories of seed, care should be taken to note any weeds present which may be specified on the label and the germination percentage. Unfortunately, States have different requirements for certified seed. Consequently, certified seed from interstate can contain weeds which, while not declared noxious weeds in the State it is grown, may be a declared noxious weed in New South Wales. Also, some States have much lower minimum germination percentages, so the details on the label become very important.

It is worth considering that a few dollars saved on “cheap” seed may mean a lot of extra dollars spent on herbicides trying to eradicate an unwanted weed.

New Species and Varieties	Minimum Rainfall Requirement	Attributes
Subterranean Clover cv Dalkeith	425 mm	Very early maturity Very hardseeded Excellent persistence Dwalganup alternative
cv Junee	500 mm	Improved hardseed Root rot tolerant Clover scorch resistant Woogenellup alternative Mid-season maturity
cv Karridale	650 mm	Clover scorch tolerant Later maturing Improved hardseed Tolerant red-legged earthmite Mount Barker alternative
Barrel Medics
cv Paraggio	400 mm	Jemalong replacement Tolerant spotted and blue green aphids Central and Southern NSW
cv Sephi	400 mm	Jemalong replacement Very tolerant of spotted and tolerant of blue green aphids Central and Northern NSW
cv Parahinga	275 mm	Early maturing Tolerant of spotted and blue green aphids
Murex Medic
cv (yet to be named)	475 mm	Mid-season maturity Very hardseeded Tolerant of mildly acid soils Sown in mixture with subclover Available 1989
Serradella
cv Tauro	450 mm	Maturity between Pitman and Uniserra
		Good winter growth Tolerant of acid soils Available 1988
cv CS 046.1 (to be named)	500 mm	Pitman replacement Suited to wetter areas than Tauro Very tolerant aluminium and acid soils
		Very hardseeded Available 1988
Balansa Clover
cv Paradana	500 mm	Very tolerant clover scorch High level of hardseed Very small seeded Tolerant of waterlogging Regenerates each year
New Species and Varieties	Minimum Rainfall	Attributes
Persian Clover	Requirement
cv SA 18920	550 - 600 mm	Earlier maturing than Maral Greatly increased hardseed Expected to regenerate Very high feeding value Available 1988

Introduction

How can pasture legumes be improved?

New Species And Varieties

Subterranean Clover

Seed Quality

Further Reading

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