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
Segregation of compact growth types in certain apple seedling progenies
Two-year-old apple seedlings of six progenies resulting from crosses between cultivars of standard growth or their compact mutants were classified for standard or compact growth type. A natural compact mutant of McIntosh (Wijcik) in combination with Golden Delicious transmitted compact growth habit to 43.9% of its progeny, whereas the radiation-induced compact mutant of McIntosh (8F-2-27), in the same combination did not transmit this characteristic. Number of side shoots, internodal length, and the ratio of length to diameter of one-year-old shoots were useful characteristics in distinguishing between the standard and compact growth types in two-year-old seedling trees. As the segregation of seedlings of compact growth habit is of great interest both from theoretical and practical aspects, a careful assessment of the transmissibility of compactness by mutant and non-mutated cultivars in various cross-combinations is suggested.
Crop load and water stress effects on daily stem growth in peach (Prunus persica).
We investigated crop load and water stress effects on diurnal stem extension growth of field-grown peach (Prunus persica (L.) Batsch) trees. Neither the presence of fruit nor reduced irrigation significantly altered the timing of diurnal fluctuations in stem growth rate. Stems with subtending fruit had significantly reduced growth compared to stems with no subtending fruit. Crop load had no significant effect on relative stem extension rates and the majority of the reduction in absolute growth was the result of a smaller zone of elongation in fruit-bearing stems than in stems with no subtending fruit. Fruit removal did not increase growth rates within 24 h. When irrigation was reduced, the length of the stem elongation zone and total daily stem growth were significantly decreased relative to well-irrigated controls and the decreases were highly correlated with stem water potential. Compared with well-irrigated controls, relative stem extension rates of water-stressed trees were reduced at several times during the 24-h period, but the degree of reduction was not proportional to the difference in stem water potentials between the treatments.