THE SYNTHETIC PRODUCTION OF OAT VARIETIES RESISTANT TO RACE 6 AND CERTAIN OTHER PHYSIOLOGIC RACES OF OAT STEM RUST

1937 ◽  
Vol 15c (2) ◽  
pp. 58-69 ◽  
Author(s):  
J. N. Welsh
Keyword(s):  
Seedling Stage ◽  
The Other ◽  
Puccinia Graminis ◽  
Stages Of Growth ◽  
Boot Stage ◽  
Advanced Stages ◽  
Physiologic Races ◽  
Pure Lines ◽  
Heading Stage ◽  
Single Variety

At the present time, oat varieties that are classed as resistant to Puccinia graminis Avenae Erikss. & Henn. are only resistant to a certain number of the ten physiologic races. With the object of combining in a single variety resistance to as many races as possible, a cross was made between the varieties Hajira Strain and Joanette Strain. Hajira Strain is susceptible to Races 4, 6, 8, and 10, and Joanette Strain to Races 2, 6, 7, 8, and 9. The latter variety gives an indeterminate reaction to Races 5 and 10. Both parents are susceptible to Races 6 and 8.From this cross 93 pure lines were obtained. Under greenhouse conditions, 71 were resistant at the seedling stage to Race 6 at 60° F. At 65°–70° F., approximately one-third of these were resistant to Race 6, one-third semi-resistant, and one-third susceptible. At more advanced stages of growth, namely, fifth-leaf, boot, and heading, representative lines from each of these classes were resistant to Race 6 at 60° F. At 65°–70° F. all showed regional resistance: at the fifth-leaf stage, the tip end of the uppermost leaf only was susceptible; at the boot stage, numerous pustules were present on the uppermost node and internode but the remaining parts were free from infection; at the heading stage, only one or two fairly large pustules occurred on the uppermost node or internode.Six lines that were consistently resistant to Race 6 at 60° F. and 65°–70° F. were tested at the seedling stage at 60°, 65°–70° F., and 75°–80° F., to Races 1, 2, 3, 4, 5, 6, 7, 8, and 10. At the low and intermediate temperatures, these lines were resistant to the nine races. At the high temperature, they were susceptible to Race 6, gave an indeterminate reaction to Races 1, 4, and 5, and were resistant to all the other races.Under field conditions, six lines classed as resistant at 65°–70° F., five classed as semi-resistant, and four as susceptible, were tested to Race 6. All these lines behaved similarly: infections of a semi-resistant type appeared on the uppermost internodes, while other parts of the plants were free from infection.The standard varieties used as checks, namely, Hajira Strain, Joanette Strain, White Russian, and Victory, were susceptible to Race 6 in all the greenhouse experiments, and, with the exception of White Russian, in the field test. In the latter test, White Russian was semi-resistant.

EFFECT OF PASMO DISEASE ON SEED YIELD AND THOUSAND KERNEL WEIGHT OF FLAX

1950 ◽  
Vol 28c (5) ◽  
pp. 493-512 ◽  
Author(s):  
W. E. Sackston
Keyword(s):  
Seed Yield ◽  
Yeast Extract ◽  
Kernel Weight ◽  
Potato Dextrose Agar ◽  
Seedling Stage ◽  
Flowering Stage ◽  
Thousand Kernel Weight ◽  
Stages Of Growth ◽  
Positive Correlations ◽  
Field Plots

The pasmo pathogen sporulated freely on potato dextrose agar containing yeast extract. Spores suspended in water with gelatin as a spreader–sticker were sprayed onto flax plants at different stages of growth in field plots. Heaviest infections of pasmo resulted from inoculations at the flowering stage, lighter infections from inoculations on seedlings, and lightest infections from inoculations on ripening plants. Diluting the concentration of spores in the inoculum reduced disease intensity. The four flax varieties in the tests differed in reaction to pasmo. In decreasing order of susceptibility they were: Viking, Redwing, Royal, and Crystal. Heavy infections of pasmo caused premature ripening and reduced the seed yield and weight per thousand kernels of all four varieties. The effects of pasmo infection on seed yield and kernel weight were similar to those caused by a hot, dry climate, and by flax rust. Seed yield and kernel weight were reduced most markedly by inoculation at the flowering stage, less severely by inoculation at the seedling stage, and least of all by inoculation at the time of ripening. Seed yield and kernel weight from plots inoculated when the plants were ripening did not differ significantly from the uninoculated checks. Highly significant positive correlations between the data for seed yield and kernel weight indicated that much of the loss in yield resulted from a reduction in the size of individual seeds.

scholarly journals INFLUENCE OF PERIODIC SHADING ON THE LENGTH AND SOLIDNESS OF THE INTERNODES OF RESCUE WHEAT

1960 ◽  
Vol 40 (1) ◽  
pp. 183-187 ◽  
Author(s):  
N. D. Holmes ◽  
R. I. Larson ◽  
L. K. Peterson ◽  
M. D. MacDonald
Keyword(s):  
Light Intensity ◽  
Cross Sections ◽  
Strongly Correlated ◽  
Boot Stage ◽  
Stem Solidness ◽  
Heading Stage

Shading at the initiation of elongation shortened the internodes of Rescue wheat whereas shading later in the elongation period caused the internodes to elongate as much as or more than if they had not been shaded.The solidness of the bottom Internode, 1, was reduced mainly by shading from the 2-leaf to the boot stage, while that of Internodes 2 and 3 was reduced mainly by shading from the 4-leaf to the boot stage. The solidness of Internode 4 was reduced mainly by shading from the boot to the heading stage. The solidness in the lower 3 internodes was affected by reduction in light intensity even after the boot stage. Severe lodging occurred only in stems shaded from the boot to the heading stage.Two methods were used for rating stem solidness, namely, measurement in the split stem of proportion of the internode filled with pith, and classification of solidness of cross-sections at designated points in each internode. They were strongly correlated and appeared to give equally accurate estimates of solidness, although their degrees of sensitivity varied with the amount of stem solidness present.

PHYSIOLOGIC RACES OF PUCCINIA GRAMINIS TRITICI IN CANADA, 1919 TO 1944

1946 ◽  
Vol 24c (2) ◽  
pp. 26-38 ◽  
Author(s):  
Margaret Newton ◽  
T. Johnson
Keyword(s):  
Recent Change ◽  
Economic Importance ◽  
Puccinia Graminis ◽  
Minor Importance ◽  
Eastern Canada ◽  
Minor Significance ◽  
The Common ◽  
Physiologic Races ◽  
Different Parts ◽  
Prairie Provinces

During the period 1919 to 1944, 65 physiologic races were identified from a total of 4543 isolates derived from uredial collections of Puccinia graminis Pers. var. Tritici Erikss. & Henn. Forty-nine races were obtained in the Prairie Provinces from a study of 3475 isolates; 40 in Eastern Canada from 1013 isolates, and 12 in British Columbia from 55 isolates. During this period, the predominant races have shown notable fluctuations in their prevalence. Races 36, 17, and 21 were the most common races until shortly after 1930 and were largely responsible for the severe rust losses suffered by Marquis and other common wheats during the decade preceding that year. Races 34 and 49 were collected frequently from 1927 to about 1935. All of these races diminished greatly in their prevalence between 1930 and 1936, whereas race 56, which was first collected in Canada in 1931, has become the predominant race since 1934. It was this race that played a major part in the stem rust epiphytotic of 1935. Another recent change in the racial population was a recrudescence in 1940 of race17, which for several previous years had been of minor importance. In 1941 this race challenged the pre-eminent position of race 56 but receded again in succeeding years to minor significance.The distribution of races is somewhat similar but not identical in different parts of Canada. Races 36 and 21 have been relatively more common in the Prairie Provinces than in Eastern Canada, while the contrary is true of race 38. Only about a dozen of the 65 races collected in Canada have thus far assumed much economic importance, a few others may be considered of minor significance, but at least two-thirds of the races have been found only occasionally and have, for reasons not fully understood, failed to gain even a limited distribution.A comparison of the number of physiologic races collected in Eastern Canada and the Prairie Provinces, respectively, has indicated a somewhat greater variety of physiologic races in the former region, a condition that may perhaps be explained by the presence of the common barberry in many localities in Eastern Canada.

The egg-parasite of Sialis lutaria: a study of the influence of the host upon a dimorphic parasite

Parasitology ◽  
1937 ◽  
Vol 29 (4) ◽  
pp. 539-553 ◽  
Author(s):  
George Salt
Keyword(s):  
Special Interest ◽  
The Other ◽  
Trichogramma Evanescens ◽  
Winged Form ◽  
Egg Parasite ◽  
Pure Lines

1. Nearly a quarter of a million eggs of Sialis lutaria were collected at Cambridge in 1936. About 0·6 per cent of them were attacked by a parasite.2. The egg-parasite of Sialis is distinct from Trichogramma evanescens, and is to be called T. semblidis (Aurivillius).3. The male of Trichogramma semblidis occurs in two forms. Neither consists merely of imperfect or degenerate individuals of the other, for the two forms are equally large and differ constantly and fundamentally in several characters. The species, therefore, exhibits true dimorphism.4. Rearing experiments involving isolated pure lines show that it is principally the host that determines which form of the parasite shall emerge. Males reared on Sialis are of the apterous form; those reared on three species of Lepidoptera are of the winged form.5. The dimorphism of T. semblidis is discussed in relation to other examples of dimorphism in the Hymenoptera. It is shown to have several features of special interest.

Are mesic communities less drought-resistant? A study on moisture relationships in dry sclerophyll forest at Inglewood, South Australia

1962 ◽  
Vol 10 (2) ◽  
pp. 106 ◽  
Author(s):  
HA Martin ◽  
RL Specht
Keyword(s):  
Soil Moisture ◽  
South Australia ◽  
Seedling Stage ◽  
The Other ◽  
Drought Period ◽  
Available Water ◽  
Sclerophyll Forest ◽  
Characteristic Species ◽  
Drought Resistant ◽  
Soil Moisture Reserves

Soil moisture changes under two adjacent forest associations (Eucalyptus obliqua association in the more mesic environment, E. elaeophora association in the more xeric sites) were recorded in the Inglewood area of the Mount Lofty Ranges, South Australia. The evidence indicated that the E. obliqua association had a higher index of evapotranspiration (Itr = Etr/Ew0.75) over most of the range of available water (soil moisture + rainfall) than the E. elaeophora association. The more mesic association consequently completely exhausted the stored soil moisture during periods of low rainfall and had to survive a drought period every year. The other association did not deplete the soil moisture reserves and in an average year, no drought occurred. Characteristic species of the more mesic association must be able to survive this drought period especially during the seedling stage.

THE EFFECT OF TEMPERATURE ON THE EXPRESSION OF FACTORS GOVERNING RUST REACTION IN A CROSS BETWEEN TWO VARIETIES OF TRITICUM VULGARE

1931 ◽  
Vol 5 (2) ◽  
pp. 200-207 ◽  
Author(s):  
J. B. Harrington
Keyword(s):  
Low Temperature ◽  
Genetic Factors ◽  
The Other ◽  
Effect Of Temperature ◽  
Puccinia Graminis ◽  
Genetic Studies ◽  
Triticum Vulgare ◽  
Susceptibility Factors ◽  
Different Temperatures ◽  
Genetic Hypothesis

Two random populations of F2 plants of the cross Marquillo × Marquis were tested for the reaction of their F3 seedling progenies to form 21 of Puccinia graminis tritici in the greenhouse, at average daily temperatures of 69.7° F. (the warm test) for one population, and 60.6° F. (the cool test) for the other. In both tests Marquis was susceptible and Marquillo was resistant. In the "warm test" ten families of a total of 781 were resistant. In the "cool test" five families of a total of 301 were susceptible. In both cases the results fitted a 63:1 ratio excellently, indicating the operation of three main genetic factors for rust reaction. A genetic hypothesis is proposed that explains the results on the basis of the influence of low temperature in curtailing the action of three susceptibility factors A, B and C carried by Marquis. The results indicate that genetic studies on characters which are easily influenced by environmental conditions should be made under controlled conditions, after ascertaining in advance the general effects of different temperatures, etc., upon the hybrid material to be used.

Irrigation of kenaf (Hibiscus cannabinus L.) in the Sudan

1981 ◽  
Vol 96 (3) ◽  
pp. 569-578
Author(s):  
S. M. Farah
Keyword(s):  
Previous Experiment ◽  
Growth Period ◽  
Early Growth ◽  
Hibiscus Cannabinus ◽  
The Other ◽  
Stages Of Growth ◽  
Early Maturing ◽  
Late Stages ◽  
Infiltration Method ◽  
Late Growth

SUMMARYIn one experiment during 1972 and 1973 five irrigation regimes of every 4, 6, 8 and 10 days and according to stomatal opening, as estimated by the infiltration method, were compared, using an early-maturing variety Zankawa and a late-maturing variety G51. In both experiments early crop growth was checked by the shortest and the longest irrigation intervals.Late growth, on the other hand, was promoted by the shortest intervals in both seasons. Thus the highest yield in 1972 was obtained from the 4–day regime, followed by the infiltration method, then progressively greater yields with shorter intervals. In 1973, however, the shortest interval resulted in the lowest yield, which was significantly less than the other treatments, which showed a similar trend to those of 1972.In a second experiment during 1974 and 1975 a medium-maturing variety 22/9/1 and a late–maturing variety 44/E were added to those of the previous experiment. Watering every 4 and 6 days were eliminated and watering every 12 days added, during the early growth period. Each of these regimes was given irrigation every 6, 8, 10 and 12 days during the late growth period. The early-maturing varieties yielded best when irrigated every 12 days in the early stages, and every 10 days in the late stages, whereas the late-maturing varieties yielded best when irrigated every 10–2 and 8 days in the early and late stages of growth, respectively.

PHYSIOLOGIC SPECIALIZATION OF OAT STEM RUST IN CANADA

1944 ◽  
Vol 22c (5) ◽  
pp. 201-216 ◽  
Author(s):  
Margaret Newton ◽  
T. Johnson
Keyword(s):  
Stem Rust ◽  
Wide Distribution ◽  
Puccinia Graminis ◽  
Characteristic Type ◽  
Influence Of Temperature ◽  
Physiologic Specialization ◽  
Influence Of Temperature On ◽  
Physiologic Races

An account is given of the results of studies on the physiologic specialization of Puccinia graminis Avenae Erikss. and Henn. in Canada since the inception of the work. Twelve physiologic races were identified from 2586 isolates studied during the period 1921 to 1943. The annual surveys of the prevalence of physiologic races during this period show that each year races 1, 2, and 5 have comprised the bulk of the oat stem rust in all parts of Canada. The predominance of these races has been greatest in the three Prairie Provinces, where barberry is virtually non-existent. In regions where barberry is present, other races of greater range of pathogenicity have been found more frequently than in these three provinces. The occurrence of such races, however, was sporadic until 1943, in which year races 8, 10, and 11 attained a wide distribution, apparently traceable to wind-borne urediospores from the south. There is evidence that the strains of these races present in 1943 remain in the uredial stage for much longer periods than do strains of the same races collected in previous years—a fact that may have favoured their spread in this year.The role of barberry in the origination of generally virulent physiologic races is discussed. The possibility that such races may also originate by mutation is suggested by spontaneous pathogenic changes that occurred, in the greenhouse, in a culture of race 3 that gave rise to several cultures of race 7.The effect of environment on the identification of physiologic races is demonstrated by the seasonal influences on the reaction of the variety Sevnothree to races 1 and 11. On this variety the characteristic type 1 is frequently replaced, in summer, by type x.Experiments on the influence of temperature on the reaction of adult oat plants to stem rust showed that a constant temperature of about 80° F. does not appreciably affect the reaction of White Tartar and Richland, or of other varieties with the same type of resistance, but is capable of breaking down the resistance of certain varieties derived from the crosses Hajira × Joanette, Hajira × Banner, and Victoria × (Hajira × Banner).

THE SOURCE OF RESISTANCE AND THE INHERITANCE OF REACTION TO 12 PHYSIOLOGIC RACES OF STEM RUST, PUCCINIA GRAMINIS AVENAE (ERIKSS. AND HENN.)

1951 ◽  
Vol 29 (3) ◽  
pp. 189-205 ◽  
Author(s):  
J. N. Welsh ◽  
T. Johnson
Keyword(s):  
United States ◽  
Stem Rust ◽  
Adult Stage ◽  
The United States ◽  
Puccinia Graminis ◽  
Probable Explanation ◽  
Main Gene ◽  
Physiologic Races

Resistance to 12 races of oat stem rust was unexpectedly obtained from three crosses, Hajira–Jostrain, Hajira–Richland, and Hajira–Banner, between the years 1932 and 1940. Recent investigations have shown that the Hajira parent was the source of this resistance, as 10% of plants selected from this variety were found to be highly resistant. Inheritance studies have shown that, in some crosses involving this source of resistance, two main genes are involved and in others only a single main gene. A probable explanation is that the highly resistant plants in Hajira may have differed genetically. The studies also reveal that the Hajira type of resistance to race 8, either in the seedling or adult stage, is indicative of resistance to the 12 races that occur in Canada and the United States.

scholarly journals Association between p34cdc2 levels and meiotic arrest in pig oocytes during early growth

Zygote ◽  
1995 ◽  
Vol 3 (4) ◽  
pp. 325-332 ◽  
Author(s):  
Yuji Hirao ◽  
Youki Tsuji ◽  
Takashi Miyano ◽  
Akira Okano ◽  
Masashi Miyake ◽  
...  
Keyword(s):  
Germinal Vesicle ◽  
Early Growth ◽  
Catalytic Subunit ◽  
The Other ◽  
Antral Follicles ◽  
Stages Of Growth ◽  
Mean Diameter ◽  
M Phase ◽  
Chromatin Configuration ◽  
Meiotic Competence

SummaryThe molecules involved in determining meiotic competence were determined in porcine oocytes isolated from preantral and antral follicles of different sizes. Oocytes isolated from preantral follicles had a mean diameter of 78 μm, contained diffuse filamentous chromatin in the germinal vesicle and were incapable of progressing from the G2 to the M phase of the cycle even after 72 h in culture. Oocytes from early antral follicles had a mean diameter of 105 μm, showed a filamentous chromatin configuration and about half resumed meiosis but arrested at metaphase I (MI) when cultured. Oocytes from mid-antral (3–4 mm) and large antral follicles (5–6 mm) had mean oocyte diameters of 115 and 119 μm respectively, contained condensed chromatin around the nucleolus and progressed to metaphase II (MII) in 48% and 93% of instances respectively. Analysis of p34cdc2, the catalytic subunit of maturation promoting factor (MPF), by immunoblotting indicates that the inability of small (78 μm) oocytes to resume meiosis is due, at least in part, to inadequate levels of the catalytic subunit of MPF. On the other hand, the inability of intermediate-sized (105 μm) oocytes from antral follicles to complete the first meiotic division by progressing beyond MI appears not to be limited by levels of p34cdc2, which are maximal by this stage. We postulate that an inadequacy of molecules other than p34cdc2 limits progression of MI to MII; the acquisition of these molecules during the final stages of growth may be correlated with the formation of the perinucleolar chromatin rim in the germinal vesicle.

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