THE INFLUENCE OF AGING OF SEED ON THE DEVELOPMENT OF LOOSE SMUT IN BARLEY

1961 ◽  
Vol 39 (7) ◽  
pp. 1741-1746 ◽  
Author(s):  
R. C. Russell
Keyword(s):  
Close Correlation ◽  
Barley Seed ◽  
Loose Smut ◽  
Average Amount ◽  
Average Percentage ◽  
Ustilago Nuda ◽  
Time Required ◽  
Growing Crop ◽  
Aged Seeds

For several years after their production, 15 stocks of barley seed, infected with Ustilago nuda (Jens.) Rostr., produced approximately the same average percentage of smutted plants in growth tests as the average percentage of infected embryos found in the seed. As the seed became older, this was no longer true. Some samples produced less smut after six years, while others continued to produce similar amounts up to the ninth year, but eventually all samples produced decidedly lower percentages of smut. The average percentage of smutted plants in crops grown from these samples became less with each succeeding year after the sixth in nearly all instances. In the stocks of barley seed studied, the average amount of smut in the growing crop declined from about 14% initially to only 3.2% at the end of the 11-year period.The main reason for the decline in percentage infection was the successively larger proportions of infected seeds that failed to germinate as the seed became aged, as compared with the slower loss of viability in the healthy seeds. A close correlation was found between the length of time required for aged seeds to germinate and the percentage of such seeds carrying smut in their embryos.

THE USE OF SEQUENTIAL SAMPLING IN EMBRYO TESTS FOR LOOSE SMUT IN BARLEY SEED

1961 ◽  
Vol 41 (4) ◽  
pp. 772-779
Author(s):  
R. C. Russell ◽  
B. J. Sallans ◽  
H. B. Cannon
Keyword(s):  
Sampling Method ◽  
Sequential Sampling ◽  
Barley Seed ◽  
Double Sampling ◽  
Loose Smut ◽  
Considerable Saving ◽  
Ustilago Nuda

One hundred and forty lots of barley seed were subjected to an embryo test for the mycelium of Ustilago nuda (Jens.) Rostr. Ten samples of 100 embryos were examined from each lot. It was found that the use of sequential sampling, instead of single or double sampling, in making routine tests for loose smut in barley seed, would result in a considerable saving of time and effort as far as determining whether seed stocks contain more or less than the percentage of smut set as the limit of tolerance. However, if the growers require a more exact knowledge of the level of infection in their stocks of seed, it would be preferable to examine 1,000 embryos from each stock, using the single sampling method.

A STUDY OF THE GERMINATION OF BARLEY SEED TREATED TO CONTROL LOOSE SMUT

1957 ◽  
Vol 37 (1) ◽  
pp. 59-68
Author(s):  
J. E. Machacek ◽  
H. A. H. Wallace
Keyword(s):  
Suppressive Effect ◽  
Barley Seed ◽  
Anaerobic Incubation ◽  
Loose Smut ◽  
Ustilago Nuda ◽  
Incubation Method

Tests of barley seed treated by the water-soak and the Spergon method to control loose smut (Ustilago nuda (Jens.) Rostr.) have shown that both treatments reduce germination, the Spergon treatment being the more injurious of the two. A part of the reduction may be due to an induced dormancy, but usually the ungerminated seeds are dead.Varieties of barley vary greatly in susceptibility to injury from treatment, but an equally great variation may occur among different lots of seed of the same variety. Susceptibility to the water-soak treatment is closely correlated with susceptibility to the Spergon treatment. Treatment with Ceresan M improves germination and there is a correlation between improvement by this treatment and reduction in germination caused by the water-soak or the Spergon treatment.Treatment of barley seed by the water-soak and Spergon methods destroys a part of the Alternaria contaminant usually present in such seed, but has less effect on it than Ceresan M. Treatment of the seed by the anaerobic-incubation method as used in this study had scarcely any suppressive effect on Alternaria.

THE RELATIONSHIP BETWEEN KERNEL LOCATION, KERNEL SIZE AND THE INCIDENCE OF LOOSE SMUT IN BARLEY

1963 ◽  
Vol 43 (1) ◽  
pp. 88-93 ◽  
Author(s):  
Ahmet Demirlicakmak ◽  
M. L. Kaufmann
Keyword(s):  
Artificial Inoculation ◽  
Loose Smut ◽  
Kernel Size ◽  
Ustilago Nuda ◽  
The Relationship

The association between the incidence of loose smut (Ustilago nuda) and kernel location in 6-rowed barley was studied. With artificial inoculation, kernels from the upper portion of the spike yielded the highest incidence of loose smut. Central and lateral kernels yielded similar numbers of smutted plants.With naturally infected seeds, lateral kernels produced more smutted plants than central ones. The percentage of infected seeds from the upper, middle, and lower portions of the spike varied from sample to sample.Within individual samples of nine 6-rowed varieties of barley small seeds generally produced more infected plants than large or medium-sized seeds. Since lateral kernels are normally smaller than central kernels, these results supported previous findings that the former are more subject to loose smut infection than the latter.

IDENTIFICATION OF RESISTANCE GENES IN BARLEY BY REACTIONS TO USTILAGO NUDA

1969 ◽  
Vol 49 (4) ◽  
pp. 447-451 ◽  
Author(s):  
J. G. Moseman ◽  
D. R. Metcalfe
Keyword(s):  
Hordeum Vulgare ◽  
Resistance Genes ◽  
Smut Fungus ◽  
Loose Smut ◽  
Hordeum Vulgare L ◽  
Race 1 ◽  
Ustilago Nuda ◽  
Race 2 ◽  
Or Genes ◽  
Similar Gene

The reactions of 18 cultivars and selections of barley, Hordeum vulgare L., to inoculations with three cultures of the loose smut fungus, Ustilago nuda (Jens.) Rostr., were determined. The following conclusions were derived by analyzing the reactions of cultivars Jet (CI 967) and Milton (CI 4966) and derivatives from them to inoculations with cultures 244 of race 2, 49-70 of race 2, and 10 of race 1. Jet was shown to have two genes, Un3 and Un6, and Milton, one gene, Un8. Derivatives from Jet with only gene Un6 were distinguished from those with genes Un3 and Un6. Five host selections known to have a gene or genes at the same locus as Jet were shown to have gene Un6 or a similar gene at that locus.

Influence of Temperature on Prespinning Eonymphs of the Swaine Jack-Pine Sawfly, Neodiprion swainei Midd. (Hymenoptera: Diprionidae)

1964 ◽  
Vol 96 (11) ◽  
pp. 1450-1457 ◽  
Author(s):  
J. G. Pilon ◽  
H. A. Tripp ◽  
J. M. McLeod ◽  
S. L. Ilnitzky
Keyword(s):  
Population Dynamics ◽  
Laboratory Experiments ◽  
Prime Factor ◽  
Close Correlation ◽  
Optimum Temperature ◽  
Influence Of Temperature ◽  
Pine Sawfly ◽  
Field Investigations ◽  
Influence Of Temperature On ◽  
Time Required

AbstractLaboratory experiments at various constant temperatures indicate a theoretical threshold of about 40°F. for spinning of cocoons by eonymphal larvae of Neodiprion swainei Midd. As temperatures fall below 52.5°F. the increase in mortality and time required to spin is pronounced. The optimum temperature is estimated to be around 60°F. Field investigations for three consecutive years show a close correlation between rate of spinning and temperature. Temperature is considered as a prime factor influencing the spinning of cocoons and is possibly one of the more important factors governing the population dynamics of N. swainei in the Province of Quebec.

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