1999 * X * 2

T. Enno, H. Peuša, O. Priilinn.  
  Chromosome pairing behaviour interspecies wheat hybrids F1 85
Chromosome Pairing Behaviour in Interspecies Wheat Hybrids F1. In an attempt to transfer disease resistance gene(s) the tetraploid wheat species Triticum timophee-vii and T. militinae were crossed as male parents to common wheat, Triticum aestivum cultivars ‘Fagot’, ‘Heta’, ‘Bastian’, ‘Satu’, ‘Apu’, ‘Tjalve’, ‘Runar’ and ‘Laari’. Cytological analysis of meiosis in wide hybrids F1 and parent species was undertaken. Microsporogenetic meiocytes of pentaploid hybrid plants F1 (2n=35) had a different frequency of univalents, ranging from 3 to 23, and bivalents, ranging from 5 to 16. The number of bivalents, exceeding 7 (which were formed after pairing of chromosomes belonged to the A-genomes of both parents) permits to assume that conjugation of chromosome belonged to B- and G-genomes also had place. The frequency of multivalent formation varied from 0,10 to 0, 57 per pollen mother cell.
J. Hämmal, V. Tikk.  
  ω-3 and ω-6 fatty acids, their content in feeds, poultry products and influence on the human health 89
ω-3 and ω-6 fatty acids, their content in feeds, poultry products and influence on the human health. Omega fatty acids are polyunsaturated monobasic carboxylic acids which serve essential functions in human organism. Their preventive effect on coronary heart diseases became evident during the research into the diet of Greenland Eskimos in the 1950s–1960s. High concentrations of omega fatty acids can be found in cold water fish and several plant oils. It is highly important for human health to follow the dietary balance between omega-3 and omega-6 fatty acids. The ordinary nutrients bring about the omega-3 fatty acid deficiency and for that reason the possibilities for increasing the omega-3 fatty acid content in human diet are being studied all over the world. The major factors of increasing omega-3 fatty acid level in poultry products are fish oil, linseeds oil and rapeseed oil. Decrease in organoleptic properties of enriched poultry products has caused problems. The omega-3 fatty acid concentration (particularly that of α-linolenic acid) in enriched so-called “ω-3” eggs may be even up to 10 times higher. Since 1997 the possibilities of quail and chicken egg enriching with omega-3 fatty acids have been studied in the Department of Small Animal and Poultry Breeding of the Estonian Agricultural University. Due to the reliable preliminary results the experiments on humans were also started in the Maarjamõisa Hospital.

Financial support for this study from the Estonian Science Foundation, grant No 3150, is gratefully acknowledged.

A. Ingver, M. Koppel, R. Koppel, H. Küüts.  
  Biological and cytogenetical peculiarities of spring wheat cultivars and interspecific hybrids. II. Disease and lodging resistance and lenght of growing period of spring wheat cultivars and breeding lines 123
Biological and cytogenetical peculiarities of spring wheat cultivars and inter-specific hybrids. II. Disease and lodging resistance and length of growing period of spring wheat cultivars and breeding lines. Institute of Experimental Biology and Jõgeva Plant Breeding Institute have had close cooperation to find out what are the most perspective for further breeding of spring wheat hybrid lines mostly from crosses with Triticum timopheevii and T. militinae. Growing time to heading, lodging and disease resistance of the hybrids were tested in field conditions at Jõgeva Plant Breeding Institute. The most powdery mildew and brown rust resistant turned out to be lines ‘Laari’ × T. timopheevii × ‘Laari’, ‘Troll’ × T. timopheevii × ‘Troll’, SMT 34 and 146-155 × T. timopheevii 66-3. Together with genes determing disease resistance undesirable characteristics are also transferred into hybrid material. Backcrosses must be continued with these lines to obtain earliness, better lodging resistance, higher yielding capacity and quality characteristics.
H. Kaldmäe, M. Metsaalt, M. Vadi.  
  On the intake and digestibility of grain silage 129
On the intake and digestibility of grain silage. Three trials were carried out during the investigation. In the 1st trial the effect of oat grain silage preserved with Ensimax on intake and productivity were investigated. In the 2nd trial on rams, digestibility of barley grain silage, prepared with AIV 2000 was determined. In the 3rd trial dry matter digestibility of oat and barley grain silage and oat and barley meal was determined in vitro.

On the basis of the results of the trials the following conclusions can be drawn:

  1. Intake of crushed oat grain silage was good. That silage can substitute compound feedingstuffs in the case sunflower oil meal and minerals are added.
  2. Oat grain silage increased milk production, mainly due to the increase of fat and protein content.
  3. Increasing the proportion of barley grain silage in the ration favoured the digesti-bility of the ration.
  4. Dry matter digestibility of barley grain silage was 76.5% and that of organic matter was 78.0%. Digestibility of barley grain silage crude protein was 77.8%.
  5. When feed digestibility is determined by in vitro methods, the coefficient of digesti-bility tends to be higher than that gained by in vivo digestion experiments.
K. Ling, V. Ploom.  
  On selenium supplementation to pregnant cows 137
On selenium supplementation to pregnant cows. Possibility of improving Se status of pregnant dairy cows and their calves by supplementing dairy cows with inorganic or organic forms of selenium was studied by supplementing a selenium-poor ration (mean Se content 0.03 ppm) of 30 dry cows. Starting two months before expected calving cows were divided into three groups and were supplemented until calving with Se as follows: P – 0.08…0.105 ppm as Se yeast, M – 0.2…0.23 ppm as sodium selenite in a mineral mixture, K – no Se supplementation. Groups P and K received selenium-free mineral mixture. One calf of control group died of nutritional muscular dystrophy (NMD). Whole blood GSH-Px activity (μkat/l) of cows and their calves at parturition and two months later was analysed as well as CK activity in blood plasma of calves at the age of two months. Analysis of variance of data revealed significant influence (P<0.001) of different Se supplementations on GSH-Px activity in whole blood of dams and their calves incorporation of Se from yeast product into GSH-Px molecule being 3.5 times more active than Se from mineral mixture. Regression analysis of all dam-calf pairs revealed strong correlation between whole blood GSH-Px activities, calves GSH-Px activities being higher than that of their dams (y=13.19+1.11x; R2=0.882). Calf whole blood GSH-Px activities of groups P, M and K were respectively 22%, 30% and 42% higher than that of their dams indicating more active Se transfer to fetus or/and its pronounced incorporation into fetal enzyme molecule when smaller amounts are available. At the age of two months GSH-Px activity of calves had decreased by 20% indicating need to start their supplementation with Se. When the data of supplemented groups compound together were compared to control group χ2 -test revealed positive influence (P<0.05) of Se supplementation to preventing NMD and elevated CK activity.
T. Sõõro.  
  Lateral force applied to a wheeled machine on turning 144
Lateral force applied to a wheeled machine on turning. The lateral force calls forth unstability of tractors and propelled farm machines on turnings. At the curvilinear motion the lateral force results from the centrifugal force and in the case of speed variation it results from the force of inertia (Figure 1).

A computational experiment is used to research the variation of the lateral force and the factors having an effect upon it. A classic tractor with the front steerable wheels is considered as a simple planar solid. The lateral force applied to the tractor is computed at two manoeuvres: at turning and in the case of changing the lane. The steerable wheel turning angle is considered to vary sinusoidally (Figure 2).

The results of the computation indicate, that in case of movement with the constant speed the lateral force varies respectively to variation of the steerable wheels turning angle. Acceleration increases the lateral force while the maximum of the lateral force is postponed with respect to the maximum of the steerable wheel turning angle. In the case of decelerated movement the lateral force decreases and obtains its maximum with anticipation when compared to the maximum of the steerable wheel angle.

The steerable wheel turning angle and the speed of tractor have the most essential effect upon the lateral force (Figures 3,4 and 6). The constructive and exploitation parameters, like mass, axle base, lateral co-ordinate of the centre of gravity also have effect on the lateral force.

The lateral force applied to the tractor consists of three components (Formulae 11 and 12). The component F1 of the lateral force caused by the centrifugal force makes up the domi-nating part of the lateral force. In the case of low speed the component F2 of the lateral force caused by the variation of the speed may appear comparable with the component F1 caused by the centrifugal force (Figure 7).

K. Annuk  
  Grain genetics and actual problems of breeding – K. Annuk 155
H. Tikk  
  Quo vadis, “Estonian Agricultural Encyclopedia”? 156
  Activities of the Academical Agricultural Society 159
  New members of the Academical Agricultural Society 163

Cloud of Keywords
acid acids activities activity agricultural analysis angle applied barley blood breeding calf calves case caused centrifugal chromosome component content cows cultivars dams determined digestibility disease effect fatty figure force grain groups growing health higher human hybrid hybrids increasing influence intake lateral lines lodging matter maximum mineral mixture months omega pairing plant poultry pregnant products ration resistance revealed selenium silage speed spring steerable studied supplementation three timopheevii tractor trial triticum turning variation wheat wheel whole ‘laari’




Estonian Academic Agricultural Society

Editor in Chief

Dr. sc. agr. Alo Tänavots


Fr. R. Kreutzwaldi 1,
51014 Tartu,






Agraarteadus : Journal of Agricultural Science 1990

Online since 
1997 * VIII * 4



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