Widespread incidence of double-stranded RNAs of unknown function in rust fungi

1990 ◽  
Vol 68 (3) ◽  
pp. 669-676 ◽  
Author(s):  
A. Pryor ◽  
M. G. Boelen ◽  
M. J. Dickinson ◽  
G. J. Lawrence

Double-stranded (ds) RNAs were found to be present in 33 of 38 collections of rust fungi, representing 15 species from four genera. This finding suggests that dsRNAs occur commonly in rust fungi. Tests were undertaken to determine the role or phenotype associated with the presence of dsRNAs. Comparisons were made between strains of Puccinia sorghi (maize rust) that had different dsRNAs and two fully isogenic strains of Melampsora lini (flax rust), one with no dsRNA and one with at least 13 dsRNAs. It was concluded that dsRNAs had no obvious effect on pathogen virulence or on growth rate as measured by rate of accumulation of leaf chitin or time to pustule eruption. Also it was demonstrated that the presence of dsRNAs had no effect on the interaction that exists between rusts over short distances in the leaf. Key words: dsRNA, rust, function, incidence.


1970 ◽  
Vol 12 ◽  
pp. 11-20
Author(s):  
M. Z. Rozainah ◽  
U. R. Sinniah

A study of an acaulescent palm, Johannesteijsmannia  lanceolata J. Dransfield was carried out in Angsi Forest Reserve Negeri Sembilan Malaysia for a period of 19 months A total of 32 adults, 24 juveniles and 32 seedlings from 3 different plots were censused every two weeks. The results showed that the average numbers of new leaves entering the crown with in the study period (19months) were: 3.3, 2.6 and 1.3 for 2.1, 1.6 and 0.8 leaves per year for adult juvenile and seedling, respectively. From the calculation it was discovered that the time spent by each leaf in the crown before it died was 8.8 years for adult and 8.4 years for juvenile. Key words: Johannesteijsmannia; Growth rate; Vegetative phenology; Arecaceae doi: 10.3126/eco.v12i0.3190 Ecoprint: An International Journal of Ecology 12: 11-20, 2005



1986 ◽  
Vol 66 (3) ◽  
pp. 817-820
Author(s):  
J. S. WALTON ◽  
B. W. McBRIDE ◽  
N. A. MARTINEAU ◽  
T. D. BURGESS

Completely pelleted diets were fed to rams under a facsimile of Ontario Ram Performance Test procedures. Twenty rams were fed for 50 d on completely pelleted rations without impairment of growth rate and without any effects on rumen health or ingestive behavior. Key words: R.O.P. testing, rams, pelleted feeds, growth rate, rumen lining



1996 ◽  
Vol 76 (2) ◽  
pp. 271-273 ◽  
Author(s):  
T. A. Van Lunen ◽  
H. Schulze

A trial was conducted to evaluate the effects of supplementing wheat- and corn-based diets with xylanase on growth performance and FCR of pigs from 10 to 18 wk of age. Seventy-tow castrated male pigs were assigned to pens of two and in a randomized block design to six dietary treatments consisting of diets containing 60% wheat, 40% wheat and 20% corn, and 20% wheat and 40% corn with and without supplementation with xylanase. Feed and water were available ad libitum. Xylanase supplementation improved growth rate and FCR by 9.2 and 5.3%, respectively, regardless of level of wheat and corn inclusion. Key words: Pig, growth, feed enzyme, Trichoderma longibrachiatum xylanase, wheat, corn



1996 ◽  
Vol 76 (3) ◽  
pp. 483-485 ◽  
Author(s):  
E. O. Kenaschuk ◽  
K. Y. Rashid ◽  
G. H. Gubbels

AC Emerson, a medium-early maturing oilseed flax (Linum usitatissimum L.), was released by Agriculture and Agri-Food Canada, Agri-Food Diversification Research Centre, Morden, Manitoba, in 1994. The cultivar has high oil quality, medium-large seed size and was high yielding in both early and late seeding tests in the Black and the Brown Soil zones of Manitoba and Saskatchewan. Because of its chlorosis tolerance, it is particularly well suited to the calcareous soils of Manitoba. It is immune to North American races of rust caused by Melampsora lini and moderately resistant to wilt caused by Fusarium oxysporum f. sp. lini. Key words: Flax, oilseed, Linum usitatissimum L., cultivar description



1992 ◽  
Vol 72 (2) ◽  
pp. 403-408 ◽  
Author(s):  
R. M. McKay

The impact of continued selection for reduced backfat thickness and improved growth rate on weight changes in Yorkshire and Hampshire sows, from breeding as gilts to weaning their second litter, was studied. Results suggest that some sow weight changes may have been influenced by selection pressure exerted. Key words: Sows, Canadian Yorkshire, Hampshire, liveweight change



1991 ◽  
Vol 71 (3) ◽  
pp. 905-907
Author(s):  
R. A. Kemp ◽  
S. F. Lane ◽  
Y. M. Berger

Crossbred ewe lambs were used to examine effects of shearing and prebreeding ram exposure on age at puberty and pregnancy rate. Shearing did not significantly affect age at puberty or growth rate of ewe lambs. Prebreeding ram exposure and/or shearing did not influence pregnancy rate. Key words: Shearing, ram exposure, pregnancy rate, growth



1993 ◽  
Vol 73 (1) ◽  
pp. 201-206 ◽  
Author(s):  
R. L. Cliplef ◽  
R. M. McKay

Eight generations of Yorkshire swine and seven generations of Hampshire swine, involving a total of 2300 animals of which 1350 were selected for reduced backfat thickness and increased growth rate, had concurrent increases in visceral organ weights (heart, lungs, spleen, liver and kidney). Implications are that this could amount to 0.4 kg less weight per carcass. Key words: Pigs, organs, selection, Yorkshire, Hampshire



1977 ◽  
Vol 34 (10) ◽  
pp. 1983-1988 ◽  
Author(s):  
G. R. Spangler ◽  
N. R. Payne ◽  
J. E. Thorpe ◽  
J. M. Byrne ◽  
H. A. Regier ◽  
...  

Conventional exploitation is described as an opportunistic process directed initially toward the largest members of the fish community and preferentially selecting those species for as long as the fishery persists. Some responses of percid communities to exploitation stress are similar to those previously described for marine stocks and salmonid communities. The most conspicuous responses of percids are changes in variability of recruitment, increases in growth rate, and reductions in the ages of first spawning. The least tractable and potentially most malefic responses are changes in genetic stocks and in interspecific relationships within the aquatic community. Three models are proposed for early detection of exploitation stress in fish stocks or communities. Key words: Percidae, exploitation, community ecology



Author(s):  
A.G. Gillingham

In both summer and winter, measurements were made of the rate of accumulation of dung by grazing sheep on both "easy"and "steep" land. The effect of the proportion of "easy" land (0, 25, 50, 75 or 100%) was studied in combination with grazing duration (3,6,9, 12 or 15 days) using a common pasture allowance in each situation. The rate of accumulation of dung was faster on "easy" than "steep"land, especially in summer. The rate of build-up in total dung tended to fall off during grazing and in this way largely reflected the pattern of pasture utilisation. In both seasons total dung accumulation tended to decline as the length of the grazing period increased. Correction for differences in pasture utilisation did not modify the trend and no other explanation can be offered at this time. In summer the most dung was collected from "easy" slopes when these occupied only 25% of the paddock. This effect did not occur in winter. Most dung was dropped on steep areas when they comprised the total paddock. Other less extreme variations in paddock topography had no obvious effect. Compared with other treatments the extra P provided in the highest total amount of dung on steep slopes was estimated to be about 2-3 kg ha/year. In order to achieve this, paddocks should, where possible, be fenced into topographically uniform areas either all "easy" or all "steep".



1993 ◽  
Vol 73 (2) ◽  
pp. 437-442 ◽  
Author(s):  
R. M. McKay

Index selection for reduced backfat thickness and increased postweaning growth rate resulted in increased preweaning death losses due either directly or indirectly to the sow in the Yorkshire and Hampshire breeds. This resulted in a reduced percentage of piglets weaned in the Yorkshire breed. Key words: Swine, selection index, preweaning period, mortality, survival



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