scholarly journals A novel source of resistance to verticillium wilt in alfalfa

2004 ◽  
Vol 84 (1) ◽  
pp. 401-404 ◽  
Author(s):  
B. D. Gossen ◽  
P. G. Jefferson

Verticillium wilt (VW) can cause substantial losses in yield and stand longevity in alfalfa. Resistant cultivars are available, but susceptible cultivars continue to be grown on the Canadian Prairies, where VW generally occurs only under irrigation. A study was conducted to assess the yield and persistence of 11 alfalfa lines under irrigation on three commercial fields in southern Saskatchewan. An epidemic of verticillium wilt developed at one site; the disease reaction of the susceptible Medicago sativa ssp. falcata line ‘SC Mf3713’ was similar to that of the resistant cv. Barrier. SC Mf3713 may carry a novel form of field resistance to VW, and merits further study. Key words: Medicago sativa ssp. falcata, Verticillium albo-atrum

1991 ◽  
Vol 71 (3) ◽  
pp. 871-875 ◽  
Author(s):  
H. C. Huang ◽  
M. R. Hanna

A growth-room technique was developed to evaluate alfalfa cultivars for resistance to verticillium wilt caused by Verticillium alba-atrum Reinke & Berthold. The process involves growing alfalfa seedlings in Cornell mix in Roottrainers™ and inoculating the seedlings in batches of 96, without digging, root-washing or transplanting individual seedlings. This method was shown to be effective and efficient in screening large numbers of alfalfa seedlings, approximately 1000 seedlings m−2, using little growth-room space and minimum labor. Key words: Verticillium albo-atrum, Medicago sativa, resistance, technique, alfalfa


2004 ◽  
Vol 53 (6) ◽  
pp. 812-812 ◽  
Author(s):  
M. Ghalandar ◽  
E. Clewes ◽  
D. J. Barbara ◽  
R. Zare ◽  
A. Heydari

1995 ◽  
Vol 75 (2) ◽  
pp. 469-471 ◽  
Author(s):  
S. N. Acharya ◽  
H. C. Huang ◽  
M. R. Hanna

AC Blue J alfalfa (Medicago saliva L.) was developed by the Agriculture and Agri-Food Canada Research Centre, Lethbridge, Alberta. This verticillium wilt and bacterial wilt resistant cultivar outyielded Beaver by about 8% in 4-yr trials and 15% in 7-yr trials in western Canada. It is well suited for hay production, dehydration, and silage in areas where verticillium wilt reduces alfalfa yield and stand life. Key words: Cultivar description, alfalfa, Medicago sativa


2008 ◽  
Vol 88 (3) ◽  
pp. 523-525
Author(s):  
S. N. Acharya

Dalton alfalfa (Medicago sativa) was developed by the Agriculture and Agri-Food Canada Research Centre, Lethbridge, Alberta. This cultivar, tested as LRC01CR in western Canada, is derived from parental clones that are both bacterial wilt (BW) and verticillium wilt (VW) resistant. When grown under irrigated and rainfed conditions for forage it out yielded Beaver (check) by 3%, for seed it out yielded Beaver on irrigation by 19%. Dalton is well suited to forage and seed production in western Canada where VW may be of concern. Key words: Cultivar description, alfalfa, Medicago sativa


1994 ◽  
Vol 72 (8) ◽  
pp. 1121-1125 ◽  
Author(s):  
H. C. Huang ◽  
G. C. Kozub ◽  
E. G. Kokko

Hard seeds of alfalfa (Medicago sativa L.) were artificially inoculated with Verticillium albo-atrum Reinke & Berthold and assessed for survival of the pathogen under laboratory and field conditions. When infected seeds were stored air-dry, V. albo-atrum survival was low (less than 10% after 10 months) at above-freezing temperatures (20 and 30 °C) but high (more than 90% at 10 months) at subfreezing temperatures (−20 and −10 °C). Survival of the pathogen was also low (10% at 3 months) in seeds buried in soil at 20 °C but high (90% at 10 months) at −5 °C. More than 75% of the hard seeds remained viable after 18 months of air-dry storage at −20, −10, 4, 20, or 30 °C. The incidence of verticillium wilt in alfalfa plants due to seedborne V. albo-atrum decreased with seed storage period, averaging 40% after seed was stored for 1 month and zero when seed was stored for 12 or 18 months. In field experiments, survival of seedborne V. albo-atrum decreased with increasing period of burial but at different rates in each year. The percentage of seeds with viable V. albo-atrum was greater when the seeds were buried at 10 cm compared with 5 and 2 cm (48 vs. 39 and 38%, respectively). The complete loss of viability of V. albo-atrum in infected seeds stored at 30 °C for 6 months indicates that seed-borne V. albo-atrum could be eliminated by storing alfalfa seeds at 30 °C for 1 year. Key words: Verticillium wilt, Verticillium albo-atrum, Medicago sativa, alfalfa, survival, seedborne.


2000 ◽  
Vol 80 (3) ◽  
pp. 613-615 ◽  
Author(s):  
S. N. Acharya ◽  
H. C. Huang

AC Longview alfalfa (Medicago sativa L.) was developed by the Agriculture and Agri-Food Canada Research Centre, Lethbridge, Alberta. This cultivar, tested as LRS 93-1 in Uniform Alfalfa Tests in western Canada, is highly resistant to verticillium wilt (VW) and bacterial wilt (BW) and out-yielded Beaver (check) by about 9 and 12% in dryland and irrigated locations, respectively. AC Longview is well suited for hay production, dehydration and silage in areas of western Canada, including British Columbia, where VW or BW reduces alfalfa yield and stand life. This cultivar produces good amount of seed both under dryland and irrigated conditions of western Canada. Key words: Cultivar description, alfalfa, Medicago sativa, disease resistance


1998 ◽  
Vol 78 (4) ◽  
pp. 719-722
Author(s):  
A. D. Iwaasa ◽  
K. A. Beauchemin ◽  
S. N. Acharya ◽  
J. G. Buchanan-Smith

Shearing force of alfalfa (Medicago sativa L.) stems was measured to evaluate genotype-by-year interactions. Based on mean shearing force for each stem segment and genotype clustering criteria, several genotypes had similarly shearing forces among years. Therefore, selecting genotypes with desirable shearing force characteristics to improve digestibility or intake potential of forages may be possible. Key words: Genotype, environment, shearing force, cell wall chemical constituents


1999 ◽  
Vol 79 (4) ◽  
pp. 509-517 ◽  
Author(s):  
Suwarno Suwarno ◽  
K. M. Wittenberg ◽  
W. P. McCaughey

A study was conducted to monitor nutrient and microbial count changes during wilting of alfalfa (Medicago sativa L.) in response to varying degrees of maceration at mowing. Early bloom alfalfa was mowed with either a roller-conditioner (CONV) or a macerator set to deliver four degrees of maceration during alfalfa mowing: LIGHT, LIGHT+, SEVERE, and SEVERE+. Macerated alfalfa reached 80% dry matter in 9–11 h compared with alfalfa mowed by roller-conditioner, which required 54 h. The most rapid wilting rates were associated with LIGHT+, SEVERE, and SEVERE+ maceration treatments when alfalfa was not exposed to precipitation. The wilting coefficient in the first 24 h was increased by more than 100% for the SEVERE treatment compared with alfalfa mowed using a conventional roller-conditioner in alfalfa that was not exposed to precipitation. Precipitation at 1.5 h post-mowing increased wilting time by 8.3 h to achieve 45% DM, and by 17.5 to achieve 80% DM in the SEVERE+ maceration treatment relative to alfalfa from the same conditioning treatment that was not exposed to precipitation. Precipitation at 24 h post-mowing increased wilting time to reach 80% DM by 11 h and 21 h for the LIGHT and LIGHT+ maceration treatments relative to alfalfa of the same mowing treatments not exposed to precipitation. Maceration of alfalfa resulted in a 24.2 to 26.8 h shorter wilting time relative to the conventional roller-conditioner treatment when alfalfa was exposed to precipitation at 24 h post-mowing. SEVERE and SEVERE+ maceration treatments at mowing resulted in higher (P < 0.05) neutral detergent fibre and acid detergent fibre levels post-wilting. Lactic acid bacteria populations on alfalfa tended to be higher with maceration within 1 h post-mowing (P < 0.10) and post-wilting (P < 0.08). Key words: Alfalfa, maceration, precipitation, wilting time, bacteria, nutrient profile, compressibility


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