Aust. J. Agric. Res., 1996, 47, 1131-42
Characterisation of the Kangaroo Valley ecotype
of perennial ryegrass (Lolium perenne)
M. J. BlumenthalA, K. ~ r a k a s h A.
~ , eon forte B, P. J. ~ u n n i n ~ h aBm
,
and H. I. Nicol
A
NSW Agriculture, Pasture Research Unit, PO Box 63. Berry, NSW 2535.
Victorian Department of Agriculture, Pastoral and Veterinary Institute,
Private Bag 105, Hamilton. Vic. 3300.
NSW Agriculture, Agricultural Research and Veterinary Centre,
Forest Rd. Orange, NSW 2800.
Abstract
A breeding program commenced in 1992 to produce perennial ryegrass (Lolium perenne)
cultivars based on the Kangaroo Valley perennial ryegrass (KVPR) ecotype with improved
winter and late season growth, disease resistance, and persistence. Perennial ryegrass plants
(9000) were collected from 45 sites within the Kangaroo Valley and Shoalhaven flood plain
in August 1992. Using principal component analysis, site differences were greatest for N
percentage, Mg and Na concentration, and A1 saturation. Collections were space planted
along with standard cultivars (Banks, Ellett, Embassy, Grasslands Lincoln, and Vedette) at
Berry, New South Wales (34'48's). and Timboon, Victoria (38'32'S), with 50 treatments
and 10 replicates. Plants were visually scored for seasonal yield. rust incidence. greenness,
leafiness, persistence, habit, and tiller density at both sites. At Berry, leaf angle. leaf width,
and heading date were determined.
Despite the differences in moisture, temperature, and growth indices between the 2 test
sites, seasonal yield scores (mean of 100 plants) at Berry and Timboon were highly genetically
correlated (r = 0.79-0.99). Standard cultivars were higher yielding with higher tiller density
but with a greater rust incidence than collections (P < 0.01). Collections originating from
the Shoalhaven flood plain were higher yielding with greater tiller density than plants from
the Kangaroo Valley ( P < 0.01), although differences were not as great as site of origin
differences would suggest.
Selections have been made for polycross half-sib formation. and half-sib evaluation will
take place a t a number of sites to determine the average general combining ability of parent
selections for synthetic cultivar production.
Additional keywords: genetic correlation. principal component analysis, site of origin.
Introduction
Perennial ryegrass (Lolium perenne) is the predominant grass species used in
the high rainfall dairying districts of south-eastern Australia (Bartsch and Mason
1991). The Kangaroo Valley (KVPR) cultivar is an ecotype of perennial ryegrass
that has evolved over 140 years of natural selection in the Kangaroo Valley and
adjacent coastal flood plain from early introduction of seed from the United
Kingdom (Strang 1961; Shah et al. 1990).
KVPR has a number of characteristics that make it useful in plant breeding:
(i) it is amongst the earliest flowering perennial ryegrasses in the world and,
associated with this, is one of the most winter-active (Hill 1985; Kemp 1988);
11. J. Blumenthal et al.
(ii) it is the most persistent perennial ryegrass in coastal and tableland NSW
(T. Launders, unpubl. data); and (iii) it tolerates a wide range of grazing
managements (Fulkerson et al. 1994).
Diversity for maturity date and plant habit within the ecotype suggest that
selection can be made for a range of agronomic characters. Plants grown from
seed collected from seed production paddocks had a range of 23 days in the
date of spike emergence, with prostrate types tending to be later flowering (Shah
et al. 1990). Two cultivars (Roper and Boomer; Valley Seeds Ltd) have been
developed on the basis of a small range of material from within the ecotype
(Cunningham et al. 1994). Greater gains may be made from a wider collection
of plant material and collection of material from old paddocks (not sown to
ryegrass for at least 40 years) that have not been harvested for seed.
As a first step in a breeding program, a collection of 9000 perennial ryegrass plants
from 45 individual paddocks was made. This paper provides a characterisation
of the collection grown at 2 sites for use in a plant breeding program and relates
plant characters to site of collection.
Materials and methods
Collections and collection sites
Nine thousand plants from 45 individual paddocks from the Kangaroo Valley and adjacent
Shoalhaven flood plain were collected in August 1992. The 45 collection sites were confined
within a narrow geographical area between latitudes 34'38' and 34'56's and longitudes
150°25' and 150°45'E. Many of the collection sites had not been sown to perennial ryegrass
in over 100 years and all had not been sown in the last 30 years. Some of the collected
material represented paddock populations that had not been used for seed harvest in the last
25 years and so represented genetic variability not present in the current KVPR cultivar gene
pool.
Records of annual rainfall (900-1300 mm), altitude, grazing history (dairy, cattle, sheep).
grazing pressure (light, medium, high), density of perennial ryegrass (thin, satisfactory, dense),
botanical composition of pasture, and soil characteristics [colour: texture; pH; P mg/kg: K,
Ca, Al, hlg, Na, CEC (meq/100 g): EC (DS/m): total N percentage; A1 saturation: ESP
percentage] were recorded for each collection site.
Plants were collected using a 5-cm-diameter by 7.5-cm-deep corer and placed in similar
sized plastic pots. Individual pots were hand-weeded, repotted in commercial potting mix, and
fertilised fortnightly with Aquasol[R] for the 2 months prior t o planting out in the field. The
collected plants and standard cultivars grown out in the same-sized pots (cvv. Banks. Ellett,
Embassy, Grasslands Lincoln, and Vedette) were space-planted (50-cm spacing) at Berry
(34'48's) and Timboon (38'32's) in October 1992. Both sites represent rain-fed dairy-farming
districts. Berry has a higher proportion of rainfall in summer (December-February. 32 v.
15%), a higher January mean maximum temperature (25.6OC v. 21.0°C), and a lower July
mean minimum temperature ( 6 . loC v. 7.4' C) than Timboon.
Evaluation sites
The Berry site was at the Pasture Research Unit situated within 50 km of the collection
sites. The soil for both sites is described in Table 1. The Berry soil is classified as a
red podzolic (Dr2.33; Northcote 1979) over parent rock of Berry shale with an A horizon
depth of 20 cm on an imperfectly drained medium slope. The experimental site was under
naturalised kikuyu (Pennisetum clandestinum) based pasture for a t least 30 years. The soil
at the Timboon site is classified as a yellow podzolic (Dy3.41, Northcote 1979) over marine
sedimentary material with an A horizon depth of 50 cm on an imperfectly drained medium
slope. Prior t o the establishment of the experiment, a turnip crop was sown in 1989 and an
oat crop in 1990. Before this, the site had been under perennial ryegrass-white clover pasture
for 45 years.
Characterisation of Kangaroo Valley perennial ryegrass
Table 1. Soil parameters (0-10 cm) at Berry and Timboon
Berry
Timboon
Cultural practice
The experiment a t Berry was fertilised with Pasture 13 (%: 16.0 P, 12 K, 8 . 1 S, 14.7 Ca)
a t 250 kg/ha and subsequently top-dressed with N in the form of urea (46% N) a t the rate of
50 kg N/ha on 29 January, 20 April, and 13 August 1993, and 8 February 1994, respectively.
At Timboon, 300 kg/ha of super lime (6% P, 8% S) and 200 kg/ha of Pivot 900 NPK complex
fertiliser (%: 16 N, 8 P, 9 K, 11 S) were applied before planting the trial. Subsequently, the
same amount of Pivot 900 fertiliser was applied on 15 March and 7 December 1993, and 27
March and 7 September 1994. Weeds were controlled by hand-weeding and with application
of Spray-seed (paraquatldiquat) and Roundup (glyphosate 360 g/L) with a weeding-wand or
knapsack.
Design
The experiment for both sites was a completely randomised design with 50 treatments
(45 collections and 5 standard cultivars) randomised over 10 blocks. Each treatment consisted
of 10 individual plants spaced 50 cm apart.
Measurements
Estimates (1 = low, 9 = high) of dry matter yield were made prior to cutting when the
highest yielding plants were a t the 3-leaf stage (when the third leaf on the tiller was fully
expanded; Fulkerson and Slack 1994). Yield scores were taken 11 times between 1 March
1993 and 25 July 1994 a t Berry and 12 times between 21 January 1993 and 26 July 1994 a t
Timboon. Mean seasonal (summer, autumn, winter, spring) yields were calculated for each
site. Incidence of crown rust was scored (0 = no infection, 9 = high infection) on 4 occasions
at Berry (4 May, 16 July 1993, 23 February, 26 April 1994) and 5 April 1993 a t Timboon.
Tiller density (1 = few, 9 = many tillers) was determined on 11 February 1993 a t Berry and
16 September 1993 a t Timboon. Leafiness (1 = low, 9 = high) was determined a t Berry on
11 February 1993 and a t Timboon on 14 December 1993. Leaf angle and leaf width were
measured on 12 November 1993 a t Berry. Growth habit was observed on 11 February 1993
and on 3 November 1993 a t Timboon. Greenness was estimated a t Berry on 22 December
1992, 11 February 1993, and 5 January 1994. The Berry trial was irrigated (15-20 mm/day)
between 10 and 14 January 1994 t o alleviate the effects of severe drought and heat stress.
Greenness was again observed on 20 January 1994 to note variation in recovery. Heading
dates were observed twice weekly on selected plants that were left uncut during spring within
each replicate a t Berry. A flowering score based on the number of plants heading in each row
was carried out on 13 September 1993 a t Timboon.
Statistical analysis
All parameters were subjected t o ANOVA both with and without standards, 3- and 2-way
contrasts were made between collections originating from the Shoalhaven flood plain and
those originating from the Kangaroo Valley and the standard cultivars. Due t o herbicide
M. J. Blumenthal et al.
damage a t the Berry site, one replicate was discarded from the analysis; hence, there was an
unequal number of replicates a t the sites. Because of this. the genotype and error variances
at each site and the genotype covariance between sites were estimated by residual maximum
likelihood (REAIL) using the program AI-RERIL (A. Gilmour, pers. comm. 1995). The
genotype variances and covariance were used to compute the genotype correlation.
Principal component analysis (PCA) was performed on all collection site characters and
then on 4 geographical and 14 soil characters of the 45 collection sites. PCA was carried out
on 4 morphological and 15 morphological-agronomic characters observed at Berry. PCA was
also carried out on standardised estimates of 9 common characters measured a t Berry and
Timboon, and on the combined estimate both with and without standard cultivars. Principal
components were than correlated with each of the characters included in the PCA. Bivariate
ellipses (P = 0.95) were fitted t o the PC1 and PC2 coordinates for collections from the
Shoalhaven flood plain and from the Kangaroo Valley separately.
Fig. 1. Distribution of collection sites
on the first 2 principal components for
the principal components analysis of
soil and geographical data at the site of
collection. Symbols (0,
A) represent
collection sites in the Shoalhaven flood
plain and Kangaroo Valley, respectively.
The ellipses represent the 95% confidence
around the mean of each group of
collections.
Increasing N%, Mg a n d Na
Results
Collection sites
Grazing history, grazing pressure density of perennial ryegrass, and botanical
composition were poorly correlated with the first (PC1) and second (PC2)
principal components. The results of PCA, using only 4 geographical and 14 soil
characters at the collection sites, are diagrammatically represented in Fig. 1. PC1
and PC2 accounted for 45 and 17% of variability among the sites, respectively.
Two distinct clusters formed: one comprising those sites in the Kangaroo Valley
and the other comprising those collection sites on the Shoalhaven flood plain.
All the sites were strongly acidic (pH = 4.6-5.1) and cation contents varied
as follows: Na+, very low to very high; K+, low to high; h4g2+, very low to
very high; and Ca2+, low to high (Hazelton and Murphy 1992). The N and P
content in the soil varied from low to very high values. In general, the soils of
sites in the Kangaroo Valley were less fertile than those in the Shoalhaven flood
plain. Rainfall was higher in the Kangaroo Valley than the Shoalhaven flood
plain (1329 v. 1166 mm). While long-term temperature data for Kangaroo Valley
are unavailable, there is little variation in the temperatures between Jervis Bay
on the coast and Nowra 25 km inland. The Shoalhaven flood plain, being nearer
Characterisation of Kangaroo Valley perennial ryegrass
to the coast, probably had higher humidity than Kangaroo Valley situated a
further 25 km away.
Growth indices at the two test sites
Moisture, temperature, and growth indices for the experimental period (after
Fitzpatrick and Nix 1970) are presented in Fig. 2. The moisture index a t
Timboon followed a strongly seasonal pattern with moisture being non-limiting
to perennial ryegrass growth in winter and spring. Moisture index at Berry
followed a non-seasonal pattern with moisture non-limiting to perennial ryegrass
growth in early summer 1992-93, autumn and parts of winter 1993, and winter
1994. Mean temperatures at Berry were generally higher than at Timboon over
the experimental period with temperatures limiting perennial ryegrass growth a t
both sites in winter but to a greater extent at Timboon. The growth index
(which combines moisture, temperature, and light indices) was generally higher
a t Berry than Timboon except over summer 1993-94 when moisture severely
limited growth at Berry.
Analysis of variance
The 45 collections differed significantly (P < 0.01) among themselves and from
the 5 standard cultivars for all characters a t both sites except for greenness and
leaf angle at Berry. Collections originating from the flood plain and from the
Kangaroo Valley differed for all characters at Berry except for rust score, leaf
angle, and leaf width and for all characters at Timboon except yield score in
autumn and winter 1994 and rust score.
Genetic correlations
Nine morphologic-agronomic characters common to both Berry and Timboon
were subjected to AI-REML analysis for computations of genetic correlations
(Table 2). Genetic correlations were higher when the standard cultivars were
included in the analysis. The spring 1993 yield estimate was highly correlated
between the 2 locations. The correlations for leafiness were very low.
PCA analyses
The variance accounted for by the first 2 principal components for the
morphological and morphological-agronomic characters at Berry, the standardised
estimates of 9 common characters measured at Berry and Timboon, and on the
combined estimate both with and without standard cultivars are presented in
Table 3. The variance accounted for ranged from 58 to 78% for PC1 and from
9 to 25% for PC2.
Tiller density ( r = 0.52-0 - 97) and leafiness ( r = 0.48-0-97) were highly
correlated with either PC1 or PC2 in all analyses (Figs 3 and 4). When
standard cultivars were included in the analysis, they tended to have greater
tiller density and leafiness than the collections (Figs 3b,d; 4b,d,f).
In
addition, in the morphological analysis of the Berry data, standards tended
to have wider leaves and a more erect plant habit (Fig. 3b). In turn, plants
originating from the Shoalhaven flood plain tended to have greater leafiness
and tiller density and a more erect plant habit than the plants from Kangaroo
RI. J.
Blumenthal et al.
Fig. 2. ( a ) Moisture, ( b )
temperature, and (c) growth
indices at Berry (-) and
Timboon (....) for the period
of the experiment.
0
10
120
1992
Table 2.
30
40
50
1993
60
Week
170
80
90
100
110
1994
Genetic correlations between characters measured at Berry and Timboon
Character
Autumn 1993 yield
Winter 1993 yield
Spring 1993 yield
Summer 1993-94 yield
Autumn 1994 yield
Winter 1994 yield
Tiller density
Leafiness
Crown rust incidence
With standards
Without standards
Characterisation of Kangaroo Valley perennial ryegrass
Table 3.
Percentage variability accounted for by principal components 1 and 2 for the five
separate principal components analyses
Analyses
Berry morphological
Berry morphological-agronomic
Berry standardised
Timboon standardised
Combined standardised
With standards
PC1
PC2
72
63
78
69
69
21
9
10
16
11
Without standards
PC1
PC2
67
58
63
61
61
25
11
19
20
13
Valley (P < 0.01; Figs 3a,c; 4a,c,e). In the Berry morphological-agronomic
analysis, PC1 was highly correlated (r = 0.87-0 91) with persistency (Fig. 3 b, d) .
Persistency (Fig. 3 b, d) (r = 0 73-0.84), leafiness (r = 0.45-0 83), tiller density
(r = 0.44-0.82), and plant habit ( r = 0.51-0.72) were all highly correlated with
yield estimates.
Yield ( r = 0.45-0.97) and rust (r = 0 - 71-87) incidence were highly correlated
with PC1 in the Berry morphological-agronomic analysis and the analyses using
the standardised estimates common to both Berry and Timboon. The standard
cultivars tended to have higher yield and greater rust incidence than the collections
(P < 0.01; Figs 3d, 4d-f). The yield performance of 2 of the collections was
similar t o that of 4 of the 5 standard cultivars (Fig. 4f). In turn, plants from
the Shoalhaven flood plain had higher yield than plants from Kangaroo Valley
(P < 0.01). Using the standardised Timboon (Fig. 4c,d) and the combined
data with standards (Fig. 4f), PC2 was highly correlated ( r = 0.56-0.87) with
autumn 1994 yield. Using the standardised combined data without standards,
PC2 was highly correlated (r=0.56) with winter 1994 yield (Fig. 4e).
Correlations between plant characters and collection site
In all data sets, soil P and N percentage at the collection site had significant
correlations with mean seasonal yield scores (P < 0 e01). The correlation ( r )
of yield score with soil P content ranged from 0.439 to 0.513 (Berry), 0.433
to 0.584 (Timboon), and from 0.483 to 0.583 (combined); and for total N
ranged from 0-489 to 0.608 (Berry), from 0.404 to 0.495 (Timboon), and from
0.487 to 0.491 (combined). Magnesium percentage was correlated with tiller
density: r = 0.540 ( P < 0.01; Berry), 0 -555 ( P < 0.01; Timboon), and 0.501
(P < 0.01; combined); and with leafiness: r = 0.490 (P < 0.01; Berry) and 0.431
(P < 0.01; combined). At Berry, total soil nitrogen at the collection site was
correlated with greenness (0.485; P < 0 . Ol), tiller density (0.584; P < 0. Ol),
and leafiness (0.532; P < 0.01).
Discussion
Three main points emerge from this work. (i) Despite the differences in
moisture, temperature, and growth indices between the 2 sites, the performance
of the collections and plants from the standard cultivars was highly correlated
between Berry and Timboon. (ii) Standards tended to be higher yielding and
have higher tiller density, but greater rust incidence, than the collections. (iii)
Collections from the Shoalhaven flood plain tended to be higher yielding with
greater tiller density than plants from the Kangaroo Valley, although differences
were not as great as differences in site of origin would suggest.
M. J. Blumenthal et al.
Increasing leafiness and tiller density
Increasing yield, rust and persistency
Fig. 3. Distribution of collections and standard cultivars (Ba, Banks; El, Ellett: Em,
Embassy; Ln, Grasslands Lincoln: and Ve, Vedette) on the first 2 principal components
for the principal components analysis of morphological data only ( a ) without standards
and ( b ) with standards: and of morphologic-agronomic data (c) without standards
and (d) with standards a t Berry. Symbols (0,
A) represent collection sites in the
Shoalhaven flood plain and Kangaroo Valley, respectively. The ellipses represent the
95% confidence around the mean of each group of collections.
Genetic correlation between test sites
Despite the differences in moisture, temperature, and growth indices between
the 2 sites, the performance of the collections and standard plants was highly
correlated between Berry and Timboon. At the start of the experiment, we
thought that the non-seasonal Berry environment and the more I\Iediterranean
Timboon environment would impose moisture and temperature stresses at different
times of the year and we predicted an environment xgenotype interaction, with
collections performing differently at each site. This assumes sufficient variability
between collections in adaptive plant characters. Certainly, significant differences
did occur in plant characters, but there was no interaction with test environment.
This is surprising as moisture stress did occur at different times in the year at
. . .
. . "
* "
...
-
Characterisation of Kangaroo Valley perennial ryegrass
Increasing yeild, tiller density, and rust
Fig. 4. Distribution of collections and standard cultivars (Ba, Banks; El. Ellett: Em,
Embassy; Ln, Grasslands Lincoln: and Ve, Vedette) on the first 2 principal components
for the principal components analysis of the 9 characters in common at the Berry and
Timboon sites: ( a ) without standards and ( b ) with standards at Berry, (c) without
standards and (d) with standards at Timboon, and ( e ) without standards and ( f ) with
standards for the combined data. Symbols (U, A) represent collection sites in the
Shoalhaven flood plain and Kangaroo Valley, respectively. The ellipses represent the
95% confidence around the mean of each group of collections.
M. J. Blumenthal et al.
a t Timboon, moisture stress occurred only in summer. The large within-collection
variability may mean that each collection has enormous plasticity, with mean
collection performance being similar in contrasting environments. Clearly, there
is scope for the development of a highly robust, widely adapted cultivar based
on these collections.
In a study of perennial ryegrass collected from a more diverse range of
environments than in this study, Wedderburn et al. (1989) were not able to
differentiate distinct ecotypes until the collections were stressed by either low
fertility or moisture deficit (Wedderburn et al. 1990). Imposition of stress by
growth in soils of contrasting fertility and the use of rain-out shelters may help
to differentiate the performance of individual collections.
Performance of standard cultivars
The standard cultivars were generally higher yielding than the collections but
were more rust susceptible. They were also more erect and leafier, had wider
leaves, and were more densely tillered and more persistent over the 2 years of
the experiment. All the standards were derived from New Zealand ecotypes or
from hybridisation between selections within New Zealand ecotypes and were
all later flowering than the collections. Late flowering lines often yield less in
winter (Widdup and Ryan 1993). Despite this, they were higher yielding in
the first autumn and winter than the collections. Ellett and Grasslands Lincoln
(essentially a Ruanui type with low endophyte) were also used as standards in
a New Zealand North Island hill country collection (Wedderburn et al. 1989)
and an extensive South Island collection (Widdup and Ryan 1992). Compared
with plants collected on the North Island, the standards were also more erect,
had fewer tillers, and had larger and wider leaves but were only slightly later
flowering. In contrast, when the standards were compared to the plants collected
on the South Island, they were still more erect with longer and wider leaves,
had fewer tillers, and had a similar flowering date. In our study, from the first
spring onwards, only one of the standards (Vedette) had yield scores higher than
the best of the collections. Interestingly, Vedette has not performed as well as
other cultivars, including KVPR, when grown in swards throughout coastal NSW
(T. Launders, unpubl. data).
Crown rust susceptibility was correlated with yield ( r = 0 -42-0 .go), tiller
density (0 6 2 ) , leafiness (O.72), plant habit (O.52), and maturity (0.51). This
contrasts with findings of Humphreys (1989) and Balfourier and Charmet (1991)
where rust susceptibility was negatively correlated with heading date. These
results do not support Balfourier and Charmet's (1991) suggestion that a prostrate
growth habit favours rust infection; the opposite is the case in this study with
more erect plants being more susceptible to rust. Other field studies have shown
that the more erect standards (including Ellett and Ruanui) were less rust
susceptible than the more prostrate collections from the South Island of New
Zealand (Widdup and Ryan 1992). The epidemiology of crown rust infection
is complex and the genotype of perennial ryegrass would certainly affect the
development of crown rust regardless of plant habit. We suggest that the
KVPR ecotype has developed resistance to rust strains peculiar t o eastern
Australia.
Characterisation of Kangaroo Valley perennial ryegrass
Plant characters and site of origin within the KVPR ecotype
Plants collected from the Shoalhaven flood plain were higher yielding, later
flowering, and more erect, and had greater tiller density, than plants collected
from the Kangaroo Valley proper. Soil fertility, particularly total N and Mg, and
Na cations were the site of origin characters differing most between collection
sites, with flood plain sites being generally higher in N and exchangeable cations.
Yield was correlated with soil P and N at the site of origin. This is in contrast
to work in New Zealand where plants collected from low P sites were more
vigorous than plants from high P sites (Forde and Suckling 1980). Tiller density
and greenness were also correlated with Mg level at the site of origin. Plant
characters were independent of other site of origin characteristics, including past
management and climatic factors. Whilst site of origin characters were strongly
differentiated between collection sites on the Shoalhaven flood plain and sites
in the Kangaroo Valley, the bivariate ellipses suggest that plants collected from
the 2 locations formed a single normally distributed population even though the
large number of plants sampled meant that plants from the 2 locations were
statistically different.
Future breeding
Selections have been made on the basis of individual plant performance, with
emphasis on the 2 collections that performed as well as the standards, for
half-sib formation. Half-sib evaluation a t a number of sites will be used to
determine the average general combining ability of parent selections for synthetic
cultivar production. The superior performance of the standards and a few of
the collections suggests that hybridisation with foreign germplasm not previously
introduced into the Kangaroo Valley collection would be of merit, particularly
in combining high winter and late season growth. The performance of European
tetraploids in Europe (Humphreys 1991) and in New Zealand (Widdup and Ryan
1993) suggests that induced polyploidy within adapted diploid ecotypes and
cultivars of perennial ryegrass may lead to gains in both forage yield and quality.
Tetraploidy appears t o be particularly beneficial for the combination of both
winter and late season growth (Widdup and Ryan 1993). The Kangaroo Valley
collection is currently being assessed for presence of endophyte; levels of peramine,
ergovaline, and lolitrem; Mg concentration; dry matter digestibility; and soluble
carbohydrate levels, so that issues of feed quality can also be addressed within
the plant breeding program.
Acknowledgments
This work has been funded by the Australian Dairy Research Corporation
and the Kangaroo Valley Perennial Ryegrass Seedgrowers Co-operative Ltd. The
local knowledge of Brian Morrison and the historical records freely provided by
farmers made the collection possible. Geoff Rowe, Malcolm Anderson, Bruce
Ardler, and Brian Morrison assisted in the plant collection.
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Manuscript received 8 December, accepted 21 May 1996