Preliminary assessment of selected sweet cherry hybrids regarding their resistance to black cherry aphid (Myzus cerasi Fabr.) in Bulgaria

D. Stefanova*, S. Malchev

Fruit Growing Institute, 12 Ostromila Str., 4004 Plovdiv, Bulgaria

(Manuscript received 7 July 2020; accepted for publication 11 August 2020)

Abstract. One of the main insect pests of the cherry trees in Bulgaria is Myzus cerasi (Homoptera, Aphididae). The black cherry aphids occur annually in orchards and cause yield loss or degraded quality. In 2018 and 2019, resistance to Myzus cerasi was assessed on 11 selected sweet cherry genotypes in a breeding orchard at the Fruit Growing Institute – Plovdiv. Susceptibility to aphid infestation was assessed through inspection of 100 leaf rosettes from individual tree hybrids. Some of the studied genotypes 6-132, 6-132 (1), 6-131, and 6-131 (1) were not infested by black cherry aphids in the two years of this research. Aphid colonies were observed on all other studied trees from the selected hybrids. The study is still ongoing.

Optimal use of areas in perennial vegetable crops during first year of growing

T. Dintcheva, H. Boteva, B. Arnaoudov

Maritsa Vegetable Crops Research Institute, 4003 Plovdiv, Bulgaria

(Manuscript received 25 March 2019; accepted for publication 20 May 2019)

Abstract. This paper tries to illustrate how intercropping increases the overall output of a cropping system and achieving much larger yields than sole crops by using environmental resources more fully over time or more efficiently in space. The research was conducted to establish the opportunity for optimal use of the growing area in perennial vegetables crops (Asparagus officinalis L., Rheum rhabarbarum L., Cynara cardunculus var. Scolymus, Levisticum officinale) by an intercropping system with annual vegetables (Brassica rapa subsp. Chinensis, Eruca sativa) in open field. The experiment was carried out in 2018 year in Vegetable Crops Research Institute (VCRI) Maritsa, Plovdiv, Bulgaria. Crops were grown under schemes: asparagus – 200+60/50 cm; artichoke – 200+60/90 cm; rhubarb – 200+60/90 cm; lovage – 200+60/50 cm; pak choi – 55+45+45+55/20 cm and 55+30+30+30+55/20 cm; rocket – 55+45+45+55/15 cm and 55+30+30+30+55/15 cm. As a result it was determined that the use of annual crops increases efficiency of the areas in perennial vegetables during the first year of growing. Annual vegetables pak choi and rocket grown under scheme 55 + 30 + 30 + 30 + 55/20cm and 55 + 30 + 30 + 30 + 55/15cm, respectively, are suitable for an intercropping system.

Influence of elevated platform (wire-mesh or wooden) in the cage on domestic rabbit (Oryctolagus cuniculus) activity

S. Peeva1*, E. Raichev1, D. Georgiev2, A. Stefanov3

1Department of Animal Production – Non-ruminants and Other Animals, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria,

2Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, Stara Zagora, 6000, Bulgaria

3Student Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 29 June 2017; accepted for publication 12 August 2017)

Abstract. Placing an elevated platform in the cage of rabbits is an option to increase its area. The aim of this study was to determine whether raised platform affected the overall activity of breeding rabbits and to evaluate the influence of used material (wire-mesh or wood). Two experimental groups of three male Californian rabbits at four months of age, equal body mass and condition were formed. Their activity was examined in three cage types: without platforms, with wire-meshplatformsandwithwoodenplatformsusingcameratraps.Separationofcagevolumebymeansofanelevated platformincreasedtheactivityof breeding rabbits. The rabbit activity was also influenced by the platform material. It was almost three times higher when the platform was made from wood than from wire-mesh.

Design and development of a device for measuring vacuum-pulsation parameters of milking unit

G. ineva1*, V. Vlashev1, . Tsanov2

1 epartment of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara agora, Bulgaria 2Technical College ovech, Technical University (Gabrovo), 5500 ovech, Bulgaria

device for measuring the parameters of the milking units was designed and developed. t also provides for the registration of the following parameters: value of the power vacuum, exerted pressure on an artificial teat, the structural components of pulsogram, vacuum value of milking chamber. The data obtained are submitted and saved on a computer with special software.The measuring device is created with four channels and can be used for the diagnosis of milking units irrespective of the milking installation with which they are assembled. The pressure measured in the artificial teat is an indirect indicator of the effects of milking unit on the udder.


Trends in battery cage husbandry systems for laying hens. Enriched cages for housing laying hens

H. Lukanov, D. Alexieva
Abstract. During the second half of the 20th century, in response to the growing pressure from environmental movements and organisations, European countries began to abandon rearing laying hens in battery cages, which were so far considered the most efficient husbandry system. Council Directive 1999/74/ЕC has banned housing laying hens in conventional cages effective from 1 January 2012, and only housing in enriched cages is allowed. Enriched cages are often called furnished or modified. They combine the main advantages of battery cage systems as intensity, maintenance of better hygienic parameters, restricted contact among birds and between birds and manure, better production indices, more efficient use of electrical energy, litter and veterinary medications. On the other side, furnished cages provide a larger living area for the bird, as well as perches, nests and other “enrichments” for satisfying the natural biological needs of poultry ensures the humane aspect of cage husbandry systems for laying hens. In some EC countries (Austria, Belgium), a trend to complete ban on battery cage rearing during the next decade is observed. In Switzerland, cage systems for laying hens, both in conventional and enriched cages, are completely prohibited.


Status of remote hybrids in the Poaceae: problems and prospects

H. Stoyanov
Abstract. Wide hybridization as a tool of classical breeding is a method which is successfully applied in the development of breeding programs in cultural plants. Its application is a particularly effective means to overcome the effects of biotic and abiotic stress in cultural species in Poaceae. Through wide hybridization genes for resistance to phytopathogens, insect pests, tolerance to the toxicity of aluminum, copper, cadmium are successfully transferred. The method has also high efficiency in breeding with regard to cold resistance, drought tolerance, lodging, plant height. This was achieved thanks to the phylogenetic proximity of bread wheat (Triticum aestivum) with wild species as representatives of Aegilops, Haynaldia, Agropyron, Elytrigia, Elymus, Leymus. Wide hybridization is useful in order to obtain haploid plants resulting in valuable homozygous lines. The utilization of crosses as Triticum x Zea, Triticum x Imperata, Triticum x Pennisetum allows rapid elimination of the paternal chromosomes in the meiotic division. The method of wide hybridization was successfully used to combine the genomes of valuable cultivars. Thus amphidiploid cultural species as Triticale (Triticum x Secale) and Tritordeum (Triticum x Hordeum) are successfully obtained. However, wide hybridization is related to the problems of heredity. The low percentage of crossability due to incompatibility of the stigmas of maternal plants and pollen of the paternal plants set the large number of crosses that should be handled. In many crosses there are different types of genomic incompatibility – preembryonic (receiving reduced seedset), embryonic (low percentage of germination of the seeds) postembryonic (high degree of sterility of the obtained hybrids). Low viability and the hybrid necrosis is also an essential disadvantage of wide hybrids. Using techniques such as colchicine treatment, anther culture and embryo culture are means to overcome difficulties in wide hybridization and make it a promising method of breeding in the Poaceae.


Organic farming, organic animal husbandry and organic products

І. Varlyakov

Abstract. The review analyses the state and trends for development of organic farming and animal husbandry and organic animal production in particular. The theoretical and legal background – definitions, principles, standards, registers, regulations of organic production in the EC and in our country; the requirements to organic farming including feeds, rearing conditions, breeds, treatments etc.; the prohibitions related to organic animal husbandry are reviewed. A detailed discussion is made on labelling, former and new EC organic logos, the general code number format and the rules regulating the format and function of these codes. The organic animal husbandry in Bulgaria is also reviewed with emphasis on legal initiatives, legal background, market potential, problems faced by producers, future prospects. It is anticipated that in the near future, a decline in the realisation of organic products would occur due to economic and subjective reasons. If prices of foods are mainly determined by free market competition, this would result in a negative impact on the environment and on animal welfare in particular. Only the active national policy and protection EU policies would defend the interests of producers of organic product and public interest in general.


Influence of the disk angle adjustment on the condition soil surface using surface tilling machine

M. Dallev, I. Ivanov

Abstract: The modern soil treatment theory is based on the great variety of soil and climate conditions, the rapid development of the equipment and on the application of chemicals in agriculture. One of the main conditions for efficiency of the soil treatment system is the application of a differentiated agroenvironmental approach and innovative technologies in every region. The purpose of this study is to determine the effect of the angle of adjustment of the implement of a surface tilling machine on the field surface.


Possibilities for increasing the yield and quality of asters (Callistephus chinensis L.) cut flower

N. Miteva, O. Tafradziiski
Abstract. Asters (Callistephus chinensis L.) are one of the basic annual sorts for growing in the open with big economic importance for getting cut flower. This is defined not only by their high decorative qualities because of the variety of structure and colouring of the raceme but also by their usage. The aim of the present paper is to study the influence of nitrogen fertilization on the vegetation and generational activities of the plants. Experiments were carried out as field tests. The results show that a higher dosage of nitrogen stimulates plant growth. It has also been established that mineral fertilization has a positive effect on the size of the raceme – larger racemes with bigger tubular discs are formed with many more lingulated petals, defining the fascicularity of the plants.