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THE AUSTRALIAN GERMPLASM OF PINK FLOWERING SERRADELLA SPECIES

R. Snowball

Agriculture Western Australia, Baron-Hay Court, South Perth, WA 6151

Summary. Recent introductions into Australia of germplasm of Ornithopus isthmocarpus, O. perpusillus and O. sativus were evaluated with germplasm already held in genetic resource collections. Preliminary assessment revealed that the new material expanded the genetic diversity in agronomically important characters such as flowering time, seed size and hardseededness. Analysis of the passport data gives a guide to the likely range of adaptation of the species. The increased diversity identified within O. sativus justifies ongoing research directed at producing commercial cultivars.

INTRODUCTION

The genus Ornithopus is endemic to the Mediterranean and south western Europe (6). French or pink serradella (O. sativus Brot) is native in south western France, the northern half of the Iberian peninsula and Acores. It is cultivated as a fodder plant in much of Europe where it has become naturalised. Birdsfoot serradella (O. perpusillus L.) occurs in western and west central Europe extending eastwards to Italy, Poland and southern Sweden. Moroccan serradella (O. isthmocarpus Coss.) occurs in the south western part of the Iberian peninsula and Morocco. Several intermediate species or types formed by natural crosses have been identified (5).

Most of the germplasm of French and birdsfoot serradellas was introduced into Australia between 1950 to 1953 and 1987 to 1988. With the exception of two accessions, germplasm of O. isthmocarpus was introduced in recent times by Australian collectors (3, 4). Data was first reported from field plantings at Kelmscott (1) and later at Esperance (2). Further development of the species did not proceed due to their poor persistence relative to yellow serradella.

Recent introductions of germplasm, a serious commitment to funding genetic resource activities, and a need to identify species for changing farming systems gave rise to this study. This report summarises the site data of collected germplasm, and compares the preliminary agronomic data of germplasm held before 1987 with that of recently introduced germplasm.

MATERIALS AND METHODS

Site data of collected germplasm, or passport data, was obtained from the Plant Introduction Centre, CSIRO Canberra, or extracted from published or unpublished collection reports.

Germplasm was grown at the Medina research station and at South Perth between 1991 and 1993. Material was grown as single spaced plants and sown in the first week of May. Plants grew without nutrient or water limitations. They were scored as flowering when the corolla first became visible. Growth habit was assessed using a visual rating scale. Stem thickness was measured physically. In 1993 three stems were selected at random from a single flowering plant and measured half way along its length with a micrometer. Pods were harvested and cleaned using sieves and aspiration to provide harvest weights. Seed weight was measured on duplicate samples of twenty five seeds. Seed colour and shape were assessed visually on the 50 seeds extracted for weighing. Initial hardseed per cent was assessed on four replicates of 100 pod segments subjected to 7 days in an alternating temperature cabinet (diurnal cycle from 15 to 60°C). Seed softening was assessed as above by treating separate pod samples for periods of approximately 1, 2, 4, or 6 months. Germinated seeds and hardseeds were counted after being on germination paper for 21 days at 15°C.

RESULTS

Passport data

Characteristics of the sixteen sites from which O. isthmocarpus was collected are associated with annual rainfall between 300 and 715 mm, low altitude, and acid sandy soils (Table 1). Characteristics of the eight sites from which O. perpusillus was collected are associated with an altitude of between 100 and 762 m, and mostly acid sandy soils. Other pasture legume species associated at the sites are also listed. Passport data exists for only two of the thirty four introductions of O. sativus.

Table 1. Passport data of accessions of O. isthmocarpus and O. perpusillus.

Accession

Origin

Rainfall (mm)

Altitude (m)

Soil type

Soil pH

Associated species

O. isthmocarpus

         

65306

Morocco

550

50

red brown fine loamy sand

acid

l oc mt

65307

Morocco

500

100

sand

acid

oc op ts

65308

Morocco

525

50

brown loamy sand

acid

l mt ts

65309

Morocco

590

50

red silty sand

acid

l mt ah

128585

Morocco

-

-

sandy loam

-

-

MCD112

Morocco

300

200

light brown sand

8.5

lm

MCD113

Morocco

300

200

dark grey loam

7

mi mp s oc

MCD43

Morocco

600

20

light brown sand

7

mt ts tc oc op

14440

Portugal

-

-

grey sand

-

-

48802

Portugal

-

-

sand

neutral

op oc

44708

Spain

715

100

yellow sand over red clay

-

-

SEF21

Spain

550

175

sand

6.5

ts ta oc la

SEF24

Spain

550

20

sand

6.3

op

SEF25

Spain

550

20

sand

7

tc tt op b ml

SEF26

Spain

550

10

loamy sand

6.8

tc op b mt

SEF34

Spain

400

210

loamy sand

5.8

oc tc ta l

O. perpusillus

         

49292

France

-

-

sand

-

-

65302

Morocco

550

100

red brown loamy sand

neutral

l mt

134572

Portugal

-

750

-

5

-

137405

Portugal

-

350

pale brown gritty sand

5.8

op oc

68027

Spain

800

400

brown silty sand

acid

la

134558

Spain

-

700

-

5.5

-

137406

Spain

-

762

gritty grey sand

5.8

lh oc

137407

Spain

-

716

fine brown sand

5.8

oc t

ah Astragalus hamosus; b Bisserula sp.; l Lupinus sp.; la L. angustifolius; lh  L. hispanicus; lm  L. micranthus; mi M. intertexta; ml M. litteralis; mp  M. polymorpha; mt Medicago tornata; oc  Ornithopus compressus; op O. pinnatus; s  Scorpiurus sp.; t Trifolium sp.; ta  T. angustifolium; tc  T. cherleri; ts T. subterraneum; tt T. tomentosum.

Preliminary agronomic data

Germplasm of O. isthmocarpus introduced since 1989 extends the range of flowering time, particularly in material from Spain (Table 2). Plants are more prostrate and finer stemmed than those of the older germplasm. Seeds are yellow and flat, and are distinct from seed of the other species in that they are tapered at their ends (Table 3). Seeds range considerably in their hardness, and in nearly two thirds of accessions hardseeds do not soften with the treatments imposed. There is considerable variation in seed weight between accessions from 1.2 to 2.6 mg.

Table 2. Range in flowering time, pod yield, growth habit and stem thickness.

Species/year introduced

Accessions name or number/origin

Flowering time (days)

Pod yield (g/plant)

Growth habit#

Mean stem thickness (mm)

O. isthmocarpus

         

Prior to 1987

8

119-145

177-391

p-se

3.4-4.7

1989

12 (Morocco)

114-138

134-330

p

1.9-3.0

1991

21 (Spain)

110-165

108-417

p

2.4-3.4

O. perpusillus

         

Prior to 1987

GM34 (CPI 65302)

122-132

229

p

3.0

1989

3 (Spain, Portugal)

143-170

37-125

p

2.1-2.3

O. sativus

         

Prior to 1987

25

134-153

326-398*

e-se*

3.9-4.0*

1991

ZAF5 (South Africa)

116-145

350

se

3.9

1991

5 (South Africa)

140-172

43-419

e-ve

3.3-3.7

1992

Grasslands Koha

144-178

147

se

4.1

1992

Emena

128-142

382

se

3.7

Evaluated 1991

246 (WA naturalised)

95-169

6-250

p-e

-

# p - prostrate; e - erect; se - semi erect.
* Data for the two surviving accessions.

Recent introductions of O. perpusillus are late maturing, prostrate, fine stemmed, and poor yielding (Table 2). They have very small seeds which soften readily (Table 3). GM34 flowers much earlier than the European accessions and has slightly larger seeds which do not soften.

Table 3. Range in seed weight, colour, shape, hardness and softening response.

Species/
accession

Weight (mg)

Colour

Shape

Initial hard seed (%)

Accession number Softening response

O. isthmocarpus

1.2-2.6

yellow

flat, pointed

30-99

8(+), 15(0), 1(-)

O. perpusillus

         

Post 1988

0.8-1.0

yellow

round

52-93

3(+)

GM34

1.2

yellow

round

89

1(0)

O. sativus

         

Prior to 1987 and current varieties

2.3-3.0

yellow, brown

flat, round

0-1.0

-

Post 1990

3.3-3.6

yellow, brown

flat, round

65-68

3(+)

WA naturalised

1.4-2.5

yellow

round

0-84

11(+), 1(0), 8(-)

Softening response- (+) = seeds soften; (-) = seeds harden; (0) = no change in hardseed per cent.

Recent introductions of O. sativus are both later and much earlier flowering than material held before 1987 (Table 2). Western Australian naturalised accessions differ by virtue of their large range in pod yield and growth habit as well as their early flowering. Accessions introduced prior to 1987 and current varieties are soft seeded (Table 3). Recent introductions possess seeds with a wider range in weight, and seeds that are hard initially and either soften, harden or don’t change. The hardening of seeds in one naturalised accession is associated with a decline in seed moisture content from 8.4% to 3.3%, thereafter seeds begin to soften (R. Snowball, unpubl. data).

DISCUSSION

Evaluation of two accessions of O. isthmocarpus prior to 1968 lead to the opinion that the species was agronomically inferior (1). Two other accessions tested in 1981 and 1982 gave only an average performance (2). Germplasm collected since 1987 is earlier maturing and probably more grazing tolerant through its prostrate habit than older material, and therefore better suited to the medium to high rainfall zone of the Western Australian wheatbelt. The hardseeded nature of the material should ensure persistence between periods of cropping. There is a high level of aluminium tolerance among some accessions which would be an advantage on the acid, wodjil soils (B. Nutt, pers. commun.). The recent development of a dehulling machine will overcome low initial establishment also encountered with podded, yellow serradella.

A taxonomic study by the author indicates that GM34 is closest to O. sativus, however considering it originated from Morocco it may be a new species. While GM34 may have some potential in mid season areas, the genuine accessions of O. perpusillus are unlikely to be of use except on very poor, acid soils in long season growing areas. An old accession (CPI 32013) performed very well in earlier trials (1), but no seed exists as a result of inadequate conservation. The small size of this collection warrants the further exploration for germplasm.

Germplasm of O. sativus introduced before 1987 probably represents cultivated forms of the species, exhibiting soft seeded and late maturing characteristics. Consequently it is unsuitable for most parts of Australia where serradella is adapted. It is not clear if O. sativus that is naturalised in Europe persists as a result of hardseeds, but it is likely that this plays some role in the persistence of the material naturalised at Esperance. The hardseededness and early maturity in some of the new material provides a valuable opportunity for the development of this species. Some of the material is currently being tested for suitability to a pasture/crop system on acid, sandy soils in the medium rainfall zone of the Western Australian wheatbelt. This system involves short periods of pasture (3-5 years) between similar periods of cropping designed to overcome the problem of herbicide resistant grass weeds. The upright habit and aerial seeding nature of the species would provide a relatively easy and cheap source of seed for resowing, while some hardseededness would couple short term persistence with high plant densities early in the pasture phase.

ACKNOWLEDGMENTS

Support for this project was provided by Australian woolgrowers and the Australian Government through the Australian Wool Research and Promotion Organisation.

REFERENCES

1. Bailey, E.T. 1968. Aust. Plant Introduction Rev. 5(1), 45-48.

2. Bolland, M.D.A. 1985. Aust. J. Exp. Agric. 25, 580-587.

3. Ewing, M.A. 1991. Aust. Plant Introduction Rev. 22(1), 1-13.

4. Gladstones, J.S. 1976. Aust. Plant Introduction Rev. 11, 9-23.

5. Griesinger, R. and Klinkowski, M. 1939. Der Zuchter 11, 147-161.

6. Hanf, M. 1983. BASF Aktiengesellschaft D 6-700, Ludwigshafen. pp. 351-352.

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