Narrative
Medicago sativa
LUCERNE, ALFALFA
'UQL-1'
Application No: 1999/073 Accepted: 22 Apr 1999.
Applicant: The University of Queensland, St. Lucia, QLD.
Characteristics (Table 34, Figure 43) Plant: Winter active, height tall, strong autumn and spring growth, flowering time late. Stem: at full flowering medium-long. Flower colour: 16.7% variegated. Other: Highly resistant to spotted alfalfa aphids and Phytophthora medicaginis; resistant to Colletotrichum trifolii.
Origin and Breeding Controlled pollination: In 1993, 58 Phytophthora resistant plants were generated by planting seed imported from University of Wisconsin, Madison, USA in 1980. The origins of this material are set out in Plant Disease 64: 396-397 and Crop Science 21: 271-283, and all derived from winter hardy selections. These 58 plants were selected from larger populations of plants, which grew after the prolonged storage on the basis of Phytophthora resistance, and possession of dark green leaf colour. In addition to the above, 6 plants were selected from 'Aquarius', each of which possessed both Phytophthora and Colletotrichum trifolii race 1 (anthracnose) resistance. These 64 clones were used as the maternal parents, and pollinated with pollen collected manually from 85 plants selected from 'Hallmark' for anthracnose and Phytophthora resistance. Steps were taken to ensure that each of the 85 Hallmark plants contributed pollen when making the crosses. The subsequent material went through one cycle of half-sib family selection, with intense glasshouse selection for resistance to Phytophthora and Colletotrichum. Two plants each with resistance to both pathogens were selected from each of the 64 half sib families, and polycrossing was done by hand in an insect proof glasshouse. Following glasshouse selection, the half-sib families were bulked, with equal weights of polycross seed from each half-sib family being used in preparation of the bulk. This seed (110g) was increased, through another 2 generations in the field at Keith, SA, without any intentional selection being applied, for the purpose of maintaining a broad genetic base. Sub-samples of seed from these generations have been termed gen 1 and gen 2 for the stability tests. Tests for resistance to Colletotrichum and determination of percentage of variegated flowers have been made on gen 1 and gen 2 material, and stability has been demonstrated. The maternal and paternal parents are either more dormant, or more winter active, than UQL-1. Selection criteria: Colletotrichum trifolii and Phytophthora resistance. Propagation: seed. Breeder: Prof. J.A.G. Irwin and Mrs J. M. Mackie, The University of Queensland, St Lucia, QLD.
Choice of Comparators The comparators 'Trifecta', 'Hunterfield', 'Aurora' and 'Genesis'A were selected on the basis of similar winter activity (dormancy group 7). 'Hunter River' and 'Quadrella'A were also included in some of the screening trials. The parental materials were not included because of their very diverse nature as stated above.
Comparative Trial Comparators: 'Trifecta', 'Hunterfield', 'Aurora' and 'Genesis'. Field trial location: QDPI Gatton Research Station, QLD, May 1999 - May 2000. Conditions: alluvial black soil, irrigated. Trial design: spaced plants in a randomised complete block design with 5 replicates; each replicate comprising a 15m row with 30 plants at 50cm spacing between plants. Separate seeded rows arranged in 2 replicates also with guard rows. Measurements: 60 spaced plants per cultivar were measured for plant height 2 weeks after the spring and autumn equinoxes, after being cut 2 weeks before the equinoxes; plant height was also assessed at full flowering, when flower colour was determined on every spaced plant, using the terminology of Barnes (1972).
Anthracnose screening. Trial location: University of Queensland, St. Lucia, Sep 1999. 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 (7 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 Root Rot screening. Trial location: QDPI Gatton Research Station, QLD, Mar 1999. Conditions: plants were assessed 18 months after sowing into a site naturally infested with Phytophthora medicaginis and which had been heavily irrigated. Trial design: randomised complete block with 3 replicates, plot size 5m x 5m, established at 200 plants/m2. Twenty plants were randomly selected from each plot, dug up with at least 20cm of tap root and assessed for disease reaction on a 1-5 scale (1 and 2 - resistant, 3, 4 and 5 - susceptible).
Spotted Alfalfa Aphid Screening. Trial location: New South Wales Agriculture, Yanco, NSW, May 1997. 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.
Blue-Green Aphid Screening. Trial location: New South Wales Agriculture, Tamworth, NSW, Feb 2000. Conditions: plants were grown in soil mix under glasshouse conditions for 2 weeks and inoculated with aphids (Acyrthosiphon kondoi). Trial design: 6 replicates. Measurements: After 3 weeks the seedlings are assessed as resistant or susceptible.
Prior Applications and Sales Nil.
Description: Prof. J.A.G. Irwin, The University of Queensland, St Lucia, QLD.
Table 34 Medicago varieties
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'UQL-1' *'Trifecta' *'Genesis' * 'Aurora' *Hunterfield' *'Hunter River' *'Quadrella'
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NATURAL PLANT HEIGHT IN SPRING (cm) (measured on 8-9-99)
mean 56.0 57.7 57.8 57.4 59.2 n/a n/a
std deviation 11.00 7.30 5.55 8.27 7.05 n/a n/a
LSD/sig ns ns ns ns ns n/a n/a
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NATURAL PLANT HEIGHT IN AUTUMN (cm) (measured on 3-4-00)
mean 31.8 33.3 35.9 37.0 34.1 n/a n/a
std deviation 6.73 7.93 8.32 7.63 8.17 n/a n/a
LSD/sig 6.37 ns ns ns ns n/a n/a
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STEM LENGTH AT FULL FLOWERING (cm) (measured on 5-10-99)
mean 94.6 92.6 94.1 91.4 97.0 n/a n/a
std deviation 12.52 9.25 10.82 11.33 11.94 n/a n/a
LSD/sig 4.93 ns ns ns ns n/a n/a
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TIME OF BEGINNING OF FLOWERING
late late medium-late late late n/a n/a
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FLOWER: PERCENTAGE OF PLANTS WITH VARIEGATED FLOWERS
Raw mean 16.7 0.7 0.0 2.0 0.0 n/a n/a
Transformed mean 23.9 2.1 0.0 5.1 n/a n/a
(arcsine transformed)
std deviation 3.79 4.71 0.00 7.15 0.00 n/a n/a
LSD/sig 5.03 P0.01 P0.01 P0.01 P0.01 n/a n/a
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RESISTANCE TO Colletotrichum trifolii (% seedlings resistant)
Raw mean 29.4 7.3 5.5 8.3 0.9 2.4 13.2
Transformed mean 32.5 14.5 12.6 14.7 2.99 6.9 20.1
(arcsine transformed)
std deviation 7.09 6.65 5.19 8.84 4.82 6.05 7.79
LSD/sig 5.96 P0.01 P0.01 P0.01 P0.01 P0.01 P0.01
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RESISTANCE TO BLUE-GREEN APHIDS (Acyrthosiphon kondoi)(% seedlings resistant)
mean 31.0 55.9 52.8 63.2 54.1 29.2 n/a
std deviation 14.38 16.54 5.24 5.06 19.21 22.65 n/a
LSD/sig 16.35 P0.01 P0.01 P0.01 P0.01 ns n/a
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RESISTANCE TO SPOTTED ALFALFA APHIDS (Therioaphis maculata)(% seedlings resistant)
mean 55.3 35.2 38.2 67.4 n/a 3.7 29.0
std deviation 15.07 8.29 11.1 12.14 n/a 7.77 11.95
LSD/sig 16.40 P0.01 P0.01 ns n/a P0.01 P0.01
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FIELD RESISTANCE TO PHYTOPHTHORA ROOT ROT (Phytophthora medicaginis)(% plants resistant)
mean 79.0 40.7 n/a n/a n/a n/a n/a
std deviation 15.81 23.79 n/a n/a n/a n/a n/a
LSD/sig 30.21 P0.01 n/a n/a n/a n/a n/a
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% PERSISTENCE AFTER 27 MONTHS AT GATTON RESEARCH STATION
mean 46.7 37.1 42.2 n/a n/a 41.7 n/a
std deviation 8.92 4.99 11.06 n/a n/a 8.31 n/a
*LSD/sig ns ns ns n/a n/a ns n/a
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Data given for UQL-1 is from gen 2 in all cases.
* non significant F-test on the ANOVA for these characters