Narrative
WAR 8: Lucerne
Medicago sativa
'Hallmark'
Application No: 1996/239 Accepted: 11 Nov 1996.
Applicant: CSIRO Tropical Agriculture, St Lucia, QLD and
The University of Queensland, St Lucia, QLD.
Description (see comparative table) 'Hallmark' is a winter active lucerne cultivar derived from a polycross by selection for high levels of resistance to Colletotrichum trifolii, Phytophthora medicaginis (syn P. megasperma), Stemphylium vesicarium, and leaf diseases. 'Hallmark' ranks as an 8 on a winter activity scale, and shows high levels of resistance to C. trifolii, P. medicaginis, and spotted alfalfa aphid. The proportion of its plants resistant to C. trifolii (42.3%) is significantly higher than that of 'Aquarius' or 'WL516', the proportion of plants resistant to P. medicaginis (45.0%) is not significantly different to 'Aquarius', 'Sequel HR', 'PL69', or 'WL516'; and the proportion of plants resistant to spotted alfalfa aphid (61.5%) is significantly higher than that of 'Aquarius' and 'Sequel HR'. 'Hallmark' is the on ly line with high levels of resistance to all these three pathogens/pest. In addition, there are no significant differences between the two generations of 'Hallmark' for Colletotrichum and Phytophthora resistance (only one generation was tested for spotted alfalfa aphid resistance), indicating the stability of these differentiating characters.
Origin Controlled pollination: Approximately 350 clones, predominantly from 'Trifecta' and 'Sequel' with resistance to one or more of the following pathogens (C. trifolii, P. medicaginis, Acrocalymma medicaginis, Leptosphaerulina trifoli, Stemphylium vesicarium, and Stagonospora meliloti) were intercrossed with S1 plants from 'M193' and 'WAPRS', both dominant sources of Phytophthora resistance. The material went through 2 cycles of half-sib family selection, with glasshouse selection for resistance to C. trifolii, P. medicaginis and S. vesicarium and field selection for resistance to leaf diseases. A maximum of one plant was selected from each half-sib family. Breeders: Dr. RA Bray (formerly CSIRO, Tropical Agriculture, Brisbane) and Prof. JAG Irwin (Botany Department, The University of Queensland, Brisbane). Selection criteria: resistance to C. trifolii, P. medicaginis, and S. vesicarium and leaf diseases. Propagation: seed.
Comparative Trial(s) Comparators: 'Sequel HR', 'WL516', 'Aquarius', and 'PL69'.
Field Trial. Location: UQ Gatton College, QLD, Oct 96-Jun 98. Conditions: black soil, irrigated. Trial design: spaced plants in a randomised block with 5 replicates, rows 1m apart, 50 cm spacing between plants within a row. Separate seeded rows arranged in 2 replicates for flower colour measurements, also with guard rows. Measurements: 75 spaced plants per variety were measured for plant height at spring. A high percentage of spaced plants then perished and plants from the seeded rows were used for plant height measurements for height at 4-weeks after cutting and height at full flowering.
Anthracnose Screening. Trial Location: University of Queensland, St. Lucia, Feb 97. Conditions: plants were raised in U.C. mix in flats (38 cm x 28 cm x 12 cm) in a glasshouse, 3 week old seedlings inoculated with 1 million spores/mL conidial suspension (C. trifolii race 1). Trial design: randomised complete block with 10 replicates, one row of each line (6 per flat) in each replicate. Measurements: after 7-10 days incubation all plants (25 - 30 per row) assessed for disease on a 1-5 scale (1 and 2 - resistant, 3, 4 and 5 - susceptible).
Phytophthora Screening. Trial Location: University of Queensland, St. Lucia, Feb 97. Conditions: plants were raised in U.C. mix in flats (38 cm x 28 cm x 12 cm) in a glasshouse, 5 week old seedlings inoculated with mycelial homogenate (P. medicaginis) (0.5 - 1.0 g dry wt mycelium per kg dry wt of soil mix). Trial design: randomised complete block with 10 replicates, one row of each line (6 per flat) in each replicate. Measurements: after 21 days incubation all plants dug up and roots rated for disease on 1-5 scale (1, 2 and 3 -resistant, 4 and 5 - susceptible).
Spotted Alfalfa Aphid Screening. Trial Location: Yanco, NSW, Jul 97. Conditions: plants were grown in soil mix under glasshouse conditions for 2 weeks and inoculated with aphids (Therioaphis maculata). Trial design: 6 replicates. Measurements: after 3 weeks the number of seedlings that developed trifoliate leaves was counted.
Stem Nematode Screening- Trial Location: Waite Research Precinct, SA Jun 97. Conditions: plants were grown in sand mixture in pots under glasshouse conditions 17-20o C, 50 seeds planted per pot and inoculated with stem nematodes (Ditylenchus dipsaci) (100/seed). Trial design: 3 replicates completely randomised. Measurements: After 6 weeks the number of healthy emerged seedlings were counted and compared with germination in control pots.
Prior Applications and Sales Nil.
Description: Chunji Liu, CSIRO Tropical Agriculture, St Lucia, QLD
Comparison of Lucerne varieties
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'Hallmark' *'Sequel HR' *'Aquarius' *'PL69' *'WL516'
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NATURAL HEIGHT IN SPRING (cm) (measured on 10/10/97) LSD (0.01) = 5.18
Mean 56.7b 63.9a 59.1b 59.5b 57.6b
std deviation 1.86 2.54 4.41 3.38 3.41
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PLANT HEIGHT 4 WEEKS AFTER CUTTING (cm) (measured on 14/4/98) LSD (0.01) =9.35
Mean 30.2a 30.5a 31.7a 32.1a 31.7a
std deviation 2.22 2.85 2.42 2.64 3.54
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PLANT HEIGHT AT FULL FLOWERING (cm) (measured on 8/5/98) LSD (0.01) = 8.37
Mean 36.6a 36.0a 37.4a 38.5a 38.5a
std deviation 0.35 0.97 2.31 2.97 3.96
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PERCENTAGE PLANTS RESISTANT TO Colletotrichum LSD (0.01) = 12.2
Raw mean 42.3 70.4 2.9 65.7 6.3
Transformed mean (arcsin transformed)
40.5b 57.5a 6.1c 54.4a 6.6c
std deviation 1.89 2.47 2.58 2.59 4.76
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PERCENTAGE PLANTS RESISTANT TO Phytophthora LSD (0.01) = 14.5
Raw mean 45.0 43.7 57.6 35.6 35.8
Transformed mean (arcsin transformed)
42.1ab 41.0ab 49.7a 32.6b 32.9b
std deviation 4.30 5.05 4.18 3.12 7.28
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PERCENTAGE PLANTS RESISTANT TO SPOTTED ALFALFA APHID Therioaphis maculata
LSD (0.01) = 14.09
Raw mean 61.5 38.5 22.7 48.6 62.0
Transformed mean (arcsin transformed)
55.2a 38.2bc 22.7c 44.3ab 52.4a
std deviation 10.82 5.89 9.32 12.01 9.95
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PERCENTAGE PLANTS RESISTANT TO STEM NEMATODE Ditylenchus dipsaci
LSD (0.01) = 11.06
Raw mean 36.0 29.0 25.2 16.9 28.8
Transformed mean (arcsin transformed)
36.8a 32.5ab 30.0ab 24.2b 32.2ab
std deviation 5.55 3.69 4.58 1.01 5.69
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FREQUENCY OF PLANTS WITH VERY DARK BLUE FLOWERS
none none none none none
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FREQUENCY OF PLANTS WITH VARIEGATED FLOWERS
none none none none none
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FREQUENCY OF PLANTS WITH CREAM, WHITE OR YELLOW FLOWERS
none none none none none
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TIME OF BEGINNING FLOWERING
late medium late late medium
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