COLUMNAR APPLE TREES AND THEIR VARIETIES
DOKOUPIL, L., ŘEZNICEK, V.: Columnar apple trees and their varieties. Acta univ. agric. et silvic. Mendel. Brun., 2012, LX, No. 8, pp. 37-48 The objective of the study was to evaluate selected varieties of columnar apple trees. The trees were monitored over a 3-year period and the focus was on growth, yield and health data. At the same time the quality of the harvested fruit was evaluated aer short storage. The varieties Polka, Bolero, Charlotte, Mc. Intosh Wijcik, Waltz and the control variety Golden Delicious were grown on rootstock M 9. The decisive data characterising the variety were: the height of the elongation, formation of the lateral fruiting spurs, number of fl owers and the amount of harvested fruit. No less important for growth was the health condition of the leaf area and particularly the incidence of fungus diseases; here the monitoring was carried out on six dates and was focused on apple scab and powdery mildew of apple. Infestation of the variety Charlotte with powdery mildew of apple was signifi cantly heavier than infestation of the other varieties. The variety Charlotte was also signifi cantly more aff ected with apple scab and diff ered from the other less infested varieties. The highest number of ripe fruit was produced by the variety Polka; signifi cantly less fruit was produced by the varieties Bolero, Mc. Intosh Wijcik and Waltz. The least number of fruit but the heaviest was produced by the variety Charlotte; the weight of the fruit of this variety was signifi cantly the highest. The variety Polka gave the highest yields. Evaluations of the organoleptic qualities included the appearance of the fruit; highly appraised in this respect was the control variety Golden Delicious, followed by Bolero and Mc. Intosh Wijcik. In terms of the appearance the variety Waltz received the lowest scores. The varieties Mc. Intosh Wijcik and Charlotte had the thickest skin, while the skin of varieties Polka, Golden Delicious and Waltz were of no concern. In terms of the consistence of the fl esh the highest- ranking variety was Golden Delicious, followed by Bolero and Charlotte. The juiciest variety was Golden Delicious, followed by Mc. Intosh Wijcik and Waltz; the least juicy was the variety Charlotte. The tastiest variety was the control variety Golden Delicious, followed by Mc. Intosh Wijcik and Waltz; the least tasty was the variety Bolero. In the overall sum of points appraising the fruit, fl esh and taste the variety Golden Delicious was at the top of the list, followed by Mc. Intosh Wijcik and Waltz. columnar apple trees, growth types, fruit-bearing, apple scab, powdery mildew
Inheritance of Compact Growth Type in Apple1

Test crosses within the progeny of ‘Golden Delicious’ × ‘McIntosh Wijcik’ confirmed the hypothesis that the typical growth habit of ‘McIntosh Wijcik’ is determined by a single dominant gene, Co. A small but consistent deficiency in the compact class suggested the presence of modifier gene or genes. Two independently originated natural mutants, ‘McIntosh Wijcik’ and ‘McIntosh Bendig’, were considered identical. The compact-growth seedlings, particularly the homozygous dominant genotypes from backcrosses and sib-crosses, constitute valuable breeding material. Compact segregates, evaluated as mature trees, were deemed to be suitable for very dense plantings.
Coexistence of Virulence and Antibiotic Resistance Genes in Pasteurella multocida Isolated from Diseased Rabbits
Pasteurella multocida (P. multocida)is considered a predominant pathogenic bacterial agent causing respiratory manifestations (snuffles) in rabbits with considerable economic losses and unfavorable prognosis in Egypt. A few recent P. multocida strains exhibit resistance to the most commonly used antibiotics in the veterinary field. Therefore, the present study was carried out to investigate the prevalence of both virulence and antibiotic resistance genes among P. multocida isolated from diseased rabbits in Sharkia Governorate, Egypt. Only 10 out of 100 tested rabbits` nasal swabs were finally confirmed positive for P. multocida of serogroup A by polymerase chain reaction (PCR). Antibiotic susceptibility testing of the recovered isolates revealed that they were all multidrug resistant (MDR) with a predominance of resistance to amoxicillin, ampicillin, amoxicillin/clavulanic acid, neomycin and tetracycline (100% each), followed by kanamycin and streptomycin (90% each). All the recovered isolates were further subjected to PCR screening of some common virulence and antibiotic resistance genes of interest . With the exception of toxA gene, the other virulence associated genes (ptfA, Omp87 and nanB) were found among all the examined isolates. Totally, all MDR P. multocida isolates contained at least one antibiotic resistance gene with aphA1 being the most prevalent (100%), followed by ermX gene (40%). Antibiotic resistance genotyping demonstrated the presence of multiple antibiotic resistance genes among majority of the isolates (40%) with only one isolate harboring 4 genes encoding identical resistance phenotypes. Evidentially, all MDR P. multocida isolates possessed at least 3 virulence genes accompanied by the attendance of antibiotic resistance genes. These findings evidenced that rabbits are potential sources of pathogenic P. multocida strains harboring virulence and antibiotic resistance genes. Therefore, it is evident that there is an urgent need for the judicious use of antibiotics in rabbits` treatment systems to successfully mitigate the propagation of drug resistance across P. multocida species.