References Coleman, W. K., Estabrooks, E. N. (1985). Chemical modification of cold hardiness in apple trees in eastern Canada. Can. J. Plant Sci ., 65 , 969-975. Forsline, P. L. (1983). Winter hardiness of common New York apple varieties and rootstocks as determined by artificial freezing. Proc. N.Y. State Hort Soc., 128 , 20-41. Gelvonauskis, B., Duchovskis, P., Bandaraviciene, G. (2000). Investigation of winter hardiness and cold hardiness on apple progenies. Acta Hort ., 538 , 277
Nina Krasova, Anna Galasheva and Lubov Golishkina
Dzintra Dēķena, Jānis Lepsis, Ina Alsiņa, Līga Lepse and Kersti Kahu
‘Victoria’. Acta Hort ., 976 , 355–360. Dēķena, Dz., Janes, H., Poukh, A., Alsiņa, I. (2013). Influence of rootstock on plum flowering intensity in different growing regions. Proc. Latvian Acad. Sci., Section B, 67 (2), 207–210. Galasheva, A. M., Krasova, N. G. (2013). Water regime dynamics of apple varieties having different winter hardiness. Contemp. Hort i cult ., 4 , 1–8. Gaudillere, J. P., Mang, A., Carbone, F. (1992). Vigour and non-structural carbohydrates in young prune trees. Scientia Hort ., 51 , 197–211. Grzyb, S. Z., Sitarek
Dzintra Dēķena, Heljo Jänes and Ina Alsiņa
. 4. Genkel, P.A., Oknina, E.Z. (1964). Состояние покоя и морозоустойчивость плодовых растений. (Dormancy and frost hardiness of fruit plants). Москва: Наука. 241. (in Russian). 5. Gryazev, V. (1999). Выращивание саженцев для высокопродуктивных садов (Growing of plants for highly productive orchards). Stavropol, Kavkazskiy kray. (in Russian). 6. Jänes, H., Klaas, L. & Pae, A. (2007). Winter hardiness of plum on different rootstocks in winter 2002/2003 in Estonia. Acta Horticulturae, 734, 295-298. 7. Krasavtsev, O. A
Edīte Kaufmane, Ilze Grāvīte and Laila Ikase
., Rubauskis, E., Seglina, D. (2015). Preliminary results of 1-methylcyclopropene influences on the quality of plums grown in Latvia. Proc. Latvian Acad. Sci., Section B, 70 (1), 21–28. Skrīvele, M. (1982a). Nedaudz par plūmju šķirņu ziemcietību un ražību Pūrē [Some observations about winter-hardiness and productivity of plum cultivars in Pūre]. Dārzs un Drava, No. 5, 2. lpp. (in Latvian). Skrīvele, M. (1982b). Vēlreiz par plūmēm [Again about plums]. Dārzs un Drava , No. 10, 3–5 (in Latvian). Skrīvele, M., Dēķēna, Dz. (2017). Plūmes Igaunijā un
Dzintra Dēķena, Ina Alsiņa, Valda Laugale and Kersti Kahu
REFERENCES Allona, I., Ramos, A., Ibanez, C., Contreras, A., Casado, R., Aragoncillo, C. (2008). Molecular control of winter dormancy establishment in trees. Spanish J. Agricult. Res., 6 , 201–210. Anonymous (2012). Modified method of: Volkov, F. A., Yaroslavtsev, E. N., Vlasova, T. N. Determination of winter hardiness of fruit and berry crops to cold season stressors in field and controlled conditions [Ф. А. Волков, E. H. Ярославцев, T. H. Власова. Определение устойчивости плодовых и ягодных культур к стресорам холодного времени года в полевых и
Darius Kviklys, Nomeda Kviklienė and Nobērtas Ūselis
Seven apple clones of cv. ‘Jonagold’: ‘Red Jonaprince’, ‘Jonagold Boerekamp’, ‘Jonagored Supra’, ‘Jonaveld’, ‘Jonagold DeCoster’, ‘Jonagold Novajo’ and ‘Jonabel’ were tested at the Institute of Horticulture in Babtai in 2003-2011. Significant differences among cv. ‘Jonagold’ clones were recorded in yield, fruit quality parameters and winter hardiness. The highest total yield was recorded for cvs. ‘Jonagold Boerekamp’ and ‘Red Jonaprince’, the lowest for cv. ‘Jonagold Novajo’. Average fruit weight of cv. ‘Jonagold Novajo’ was significantly lower. ‘Red Jonaprince’ fruits had the best colouration. ‘Jonagored Supra’ fruits had the best appearance according to the test panel. During winter 2009-2010, 30% of ‘Red Jonaprince’ trees suffered frost damage. No losses were recorded for ‘Jonagored Supra’. During the experiment tree losses due to frost and disease damages were 25-60% and depended on the clone.
Ilze Grāvīte and Edīte Kaufmane
The aim of the study was to determine the suitability of growing plum cultivars and hybrids of German origin in Latvian conditions. In the trial the plum cultivars and hybrids were planted at the Latvia State Institute of Fruit Growing (now, Institute of Horticulture) in spring 2008. Six W. Hartmann genotypes (cultivars ‘Tipala’, ‘Tegera’ and ‘Haganta’, and hybrids H-5102, H-3753, and H-3690) from Hohenheim University were included in the study. Prunus cerasifera was used as rootstock. The parameters evaluated were: beginning of flowering, ripening time, average yield (kg per tree), cumulative yield (kg), and average fruit weight from 2012 to 2016, and content of soluble solids from 2014 to 2016. In addition, self-fertility was evaluated in 2015 and 2016 for three cultivars and one hybrid. The winter of 2010/2011 was unfavourable, as plum orchards and most plum cultivars in Latvia suffered winter damage, but cultivars and hybrids in the trial were without damages. Significant damages were not observed in further years. Average flowering time in the four-year period for all cultivars and hybrids was the 1st or 2nd decade of May, harvest time was from the 1st decade of August to the 3rd decade of September. The earliest was hybrid H-3690, and the latest was cv.’Haganta’. The most productive was hybrid H-3690, which gave 42 kg in the 3rd year of yield and had the most rapid rise in yields. ‘Haganta’ had the biggest fruits (50 to 60 g) and highest content of soluble solids (17-18 Brix%). Self-fertility level was 40% for ‘Tegera’, 17.4% for ‘Haganta’, 14.5% for H-3690 and 0% for ‘Tipala’. Evaluation of all analysed parameters showed that ‘Tegera’ could be recommended for Latvian growers thanks to good winter hardiness in the research period. ‘Haganta’ is recommended only for warmer regions in Latvia. Hybrid H-3690 will potentially be useful for Latvian growers.
Laila Ikase, Edgars Rubauskis and Zanda Rezgale
A trial was established in 2011 with five rootstocks - MTT1, MTT4 and control B.9 (1.5 × 4 m, five replications with two trees), MTT5 and control MM.106 (2.5 × 5 m, six replications with two trees), and two cultivars - ‘Auksis’ and ‘Gita’. The evaluated parameters were: tree general condition, flowering, and yielding intensity (points), number of root suckers, average yield (kg·tree-1), yield per trunk cross section area (g·cm-2), average fruit mass (g), and amount of non-standard fruits (%). A randomised fruit sample from each cultivar-rootstock combination was put into storage, and a panel taste was performed once each season. A snowless winter occurred in 2013/2014, when soil froze to 1.5 m depth, which was critical for MM.106. Other rootstocks did not show injury. The best results were obtained for MTT4, which was similar to that of M.26 in Finland. Its vigour was similar to MM.106, and start of bearing to B.9. Rootstock MTT5 was initially grouped with medium vigour MM.106, as having 60-80 % of vigour of ‘Antonovka’ seedlings in Finland. Yet in our trial, it had vigour and start of bearing was similar to that of B.9 or slightly larger, depending on cultivar; it has a tendency to form root suckers. MTT1, ranged with B.9 in Finland, had too weak vigour. The most promising cultivar-rootstock combination was ‘Gita’ on MTT4.
Toivo Univer, Neeme Univer and Krista Tiirmaa
Long-term field trials with the apple cultivar ‘Krista’ on different vegetative rootstocks were held at the Polli Horticultural Research Centre (58°07`N, 25°32`E) in Southern Estonia in 2005-2015. Trees were grafted on 13 rootstocks: M26, M27, P59, E75, B9, B396, B491, MTT1, Supporter 1, Supporter 2, Supporter 3, Supporter 4, and MM106. The apple cultivar ‘Krista’ is well suited for growing in the climatic and soil conditions of Estonia. The cultivar performs best on vegetative rootstocks that are well-adapted to the Estonian climate: MM106, E75, B396, M26, M27, and P59. The rootstocks Supporter 1, Supporter 2, Supporter 3, and Supporter 4 did not turn out to be suited for growing in Estonia. The trees grafted on rootstocks MM106, E75, MTT1, and M26 grew taller, had a bigger crown spread and crown volume. In dense orchards with the planting scheme 4 × 1.5 m, trees with a smaller crown diameter may be grown on rootstocks MM27, P59, and Supporter 4. During the trial, the largest yields were harvested from trees grafted onto rootstocks MM106, MTT1, B396, M26, E75, and B9. Some rootstock combinations appeared to be positively related to average fruit weight in some years, but the same cannot be concluded for the whole duration of the trial.
Zoya Ozherelieva, Pavel Prudnikov and Natalia Bogomolova
of frost tolerance in winter wheat I. Model development. Eur. J. Agron., 28, 321-330. Chmir, R. A. Commercial and biological evaluation of sour cherry and sweet cherry in the central zone of Russia [Чмир, Р. А. Хозяйственно-биологическая оценка вишни и черешни в средней полосе России]. Synopsis of Candidate’s Thesis. Michurinsk. 22 pp. (in Russian). Cline, J. A., Neilsen, D., Neilsen, G., Brownlee, R., Norton, D., Quamme, H. (2012). Cold hardiness of new apple cultivars of commercial importance in Canada. J. Amer. Pomological Soc