Genetics of resistance to alfalfa mosaic virus in red clover

1997 ◽  
Vol 77 (4) ◽  
pp. 601-605 ◽  
Author(s):  
P. H. Martin ◽  
B. E. Coulman ◽  
J. F. Peterson
Keyword(s):  
Mosaic Virus ◽  
Recurrent Selection ◽  
Trifolium Pratense ◽  
Virus Disease ◽  
Alfalfa Mosaic Virus ◽  
Red Clover ◽  
Enzyme Linked Immunosorbent Assay ◽  
Polygenic Control ◽  
Trifolium Pratense L ◽  
Resistant Progeny

Virus diseases are known to reduce the yield and persistence of stands of red clover (Trifolium pratense L.). Alfalfa mosaic virus (AMV) is one of the causes of mosaic in red clover and may also cause mottling and leaf distortion. The goals of this study were to identify genotypes resistant to AMV within commercial red clover cultivars and to determine the inheritance of this resistance. Cultivars and progenies were screened for resistance by means of mechanical inoculations. Plants showing no symptoms after three successive inoculations were assayed for the presence of the virus using ELISA (enzyme-linked immunosorbent assay). Resistant plants were detected at a frequency of just over 1% in the five cultivars screened. Crosses among and between resistant (R) and susceptible (S) plants were carried out over two successive cycles of selection. In cycle 1, R × R crosses produced a higher frequency of resistant plants (19.8%) in the progenies than R × S crosses (10.9%). S × S crosses produced no resistant progeny. For crosses of resistant plants from cycle 1 progeny, (R × R) × (R × R) produced 47.8%, (R × R) × (R × S) produced 31.4% and (R × S) × (R × S) produced 29.3% resistant cycle 2 progeny. Crosses of resistant and susceptible cycle 1 plants resulted in resistance frequencies in cycle 2 which were not significantly (P < 0.05) greater than cycle 1. When only resistant plants were selected for further crossing, the percentage of resistant plants increased from 1.3 to 47.8 over the two cycles of selection. It was concluded that resistance to AMV in red clover is under polygenic control and that it should be relatively simple to select a highly resistant population through recurrent selection. Key words: Red clover, Trifolium pratense L., virus disease, alfalfa mosaic virus, recurrent selection

scholarly journals Susceptibility of ten red clover (Trifolium pratense) cultivars to six viruses after artificial inoculation

2014 ◽  
Vol 50 (No. 3) ◽  
pp. 113-118 ◽  
Author(s):  
J. Fránová ◽  
H. Jakešová
Keyword(s):  
Mosaic Virus ◽  
Trifolium Pratense ◽  
Alfalfa Mosaic Virus ◽  
Red Clover ◽  
Yellow Mosaic Virus ◽  
Mechanical Inoculation ◽  
Rt Pcr ◽  
Trifolium Pratense L ◽  
Clover Yellow Mosaic Virus ◽  
White Clover Mosaic Virus

Seedlings of Trifolium pratense L. cultivars were mechanically inoculated with Czech isolates of Alfalfa mosaic virus (AMV), Clover yellow mosaic virus (ClYMV), Clover yellow vein virus (ClYVV), Red clover mottle virus (RCMV), White clover mosaic virus (WClMV), and a newly discovered member of the Cytorhabdovirus genus. WClMV infected 75.4% of clover seedlings; cv. Rezista was the most susceptible (93.3%), while cv. Fresko was the least susceptible (58.3%). RCMV infected 59.6% of plants; the most susceptible was cv. Tempus (77.6%), the least susceptible cv. Sprint (38.3%). While WClMV infected a higher number of seedlings, RCMV revealed more severe symptoms on affected plants. On the basis of ELISA and RT-PCR results, no cultivar was susceptible to mechanical inoculation with ClYMV and cytorhabdovirus. Moreover, cvs Fresko and Sprint were not susceptible to ClYVV and AMV, respectively.

scholarly journals Forage yield and persistence of red clover progenies in two environments

2003 ◽  
Vol 60 (3) ◽  
pp. 447-452 ◽  
Author(s):  
Daniel Portella Montardo ◽  
Miguel Dall'Agnol ◽  
Nilton Rodrigues Paim
Keyword(s):  
Dry Matter ◽  
Recurrent Selection ◽  
Trifolium Pratense ◽  
Red Clover ◽  
Forage Yield ◽  
Winter Period ◽  
Forage Production ◽  
Growing Seasons ◽  
Trifolium Pratense L ◽  
Physiographic Regions

Red clover (Trifolium pratense L.) is one of the most important temperate legume species, used to lessen the lack of forage during the critical fall-winter period in Rio Grande do Sul, RS, Brazil. However, its utilization has been restricted mainly because of its lack of persistence. This work evaluates the dry matter yield and persistence of red clover half-sib progenies in two physiographic regions of RS: "Depressão Central", in Eldorado do Sul and "Encosta Superior do Nordeste", in Veranópolis. Experiments were carried out for two growing seasons and results were compared to two red clover commercial checks, Qüiñequeli and Estanzuela 116. The region of Veranópolis was more adequate for red clover forage production, enabling better yield and persistence. The best check for both locations was cultivar Estanzuela 116. At Eldorado do Sul persistence was highly affected and some progenies were superior to the best check. At Veranópolis the best check was very productive, with good persistence. The best progenies at both locations were selected to be propagated and submitted to additional recurrent selection cycles.

Selection for persistence in red clover

1999 ◽  
Vol 79 (3) ◽  
pp. 357-359 ◽  
Author(s):  
B. R. Christie ◽  
R. A. Martin
Keyword(s):  
Key Words ◽  
Root System ◽  
Recurrent Selection ◽  
Trifolium Pratense ◽  
Red Clover ◽  
Field Conditions ◽  
Fibrous Root ◽  
Phenotypic Recurrent Selection ◽  
Trifolium Pratense L ◽  
Selection For

To increase the persistence of red clover (Trifolium pratense L.), phenotypic recurrent selection was conducted under field conditions. After three cycles of selection, a strain designated as CRS-16, was developed. This strain has better persistence than the check cultivars, Florex and Marino, and has a more fibrous root system. Among 4-yr-old plants, about 10% initiated new shoots from below the crown. Key words: Red clover, Trifolium pratense L. persistence, root type

The effects of white clover mosaic virus infection on the yield of red clover (Trifolium pratense L.) in mixtures and in pure stands

1982 ◽  
Vol 98 (2) ◽  
pp. 455-460 ◽  
Author(s):  
S. W. Scott
Keyword(s):  
Virus Infection ◽  
Mosaic Virus ◽  
White Clover ◽  
Trifolium Pratense ◽  
Red Clover ◽  
Trifolium Pratense L ◽  
White Clover Mosaic Virus ◽  
Different Levels ◽  
Negative Linear Relationship ◽  
Mosaic Virus Infection

SUMMARYThe effects of white clover mosaic virus infection on the yield of two red clover varieties grown alone and in mixtures with either perennial or hybrid ryegrasses were examined. The spread of this virus within the pure clover plots was rapid. Clover drymatter yields were reduced and these losses were greater in the grass–clover mixtures than in the pure clover plots. Reductions in yield of about 70% were recorded at the first cut in mixtures of Sabtoron and Sabrina. The response of the clover to different levels of virus infection was best described by a negative linear relationship.Yields of Sabrina hybrid ryegrass increased as the levels of virus infection in the clover increased. This compensated for the losses in yield of the legume, leaving total sward yields unaffected by the virus.

RESPONSE TO SELECTION FOR STEM LENGTH IN RED CLOVER EVALUATED AT WIDE AND NARROW SPACINGS

1984 ◽  
Vol 64 (4) ◽  
pp. 925-934 ◽  
Author(s):  
S. R. BOWLEY ◽  
N. L. TAYLOR ◽  
P. L. CORNELIUS ◽  
C. T. DOUGHERTY
Keyword(s):  
Recurrent Selection ◽  
Trifolium Pratense ◽  
Red Clover ◽  
Stem Length ◽  
Yield Response ◽  
Response To Selection ◽  
Breeding Programs ◽  
Herbage Yield ◽  
Trifolium Pratense L ◽  
Selection For

Six cycles of phenotypic recurrent selection for stem length were conducted in a 91-cm-spaced planted population of red clover (Trifolium pratense L.) as a means of increasing herbage yield. The objectives of this investigation were (1) to compare the effectiveness of selection for stem length tested in transplants at wide (91 cm) and narrow (7 cm) spacings, and in row seedings and (2) to determine the effect of selection for stem length on herbage yield. Response to selection for stem length was obtained under all plantings; however, greater gains were observed at the wide transplant spacing (3.3 cm∙cycle−1) compared to the narrow transplant spacing (0.7 cm∙cycle−1) and row seeding (0.8 cm∙cycle−1). Densely spaced transplants gave performance similar to row seedings and may be of value to forage crop breeders in situations where yield or quality assessment is desired but seed supplies are insufficient for the establishment of seeded plots, such as in the early stages of breeding programs. Selection for stem length was effective in increasing herbage yield at first harvest but was associated with reduced persistance, decreased regrowth yields, and increased partitioning of dry matter towards the shoot rather than the root during seedling development. Selection for stem length in the regrowth or in the second year, rather than in the primary (seedling) growth, might have avoided the declines in persistence and regrowth yields.Key words: Trifolium pratense L., red clover, recurrent selection, stem length, density, herbage yield

Comparisons of Floral Response of Seed Lots of Dollard Red Clover, Trifolium pratense L. 1

Crop Science ◽  
1965 ◽  
Vol 5 (5) ◽  
pp. 425-428 ◽  
Author(s):  
R. J. Bula ◽  
R. G. May ◽  
C. S. Garrison ◽  
C. M. Rincker ◽  
J. G. Dean
Keyword(s):  
Trifolium Pratense ◽  
Red Clover ◽  
Trifolium Pratense L
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