Fruit production in the world is increasing continuously. Though in the past few years China and some South-American countries have extended their fruit producing areas, Europe remains to be one of the greatest fruit producers in the world. In the middle of Europe Hungary has to face several challenges as competing for market. Since yield risk has an important role in Hungarian fruit production we investigate the yield risk of two of the most important sour cherry varieties (’Újfehértói fürtös’ and ’Oblacsinszka’) grown in Újfehértó (1984-2005), moreover, two of the most important pear varieties (’Bosc Beurre’ and ’Williams’) grown in Bánfa and Zalasárszeg (1984-2009). In the examined periods we analyse yield risk with different comparative methods such as E,V-efficiency, first and second degree as well as generalized stochastic dominance methods. We conclude that the production of sour cherry variety ’Oblacsinszka’ in Újfehértó is more preferable compared to the other sour cherry varieties and pear variety ’Bosc Beurre’ in Bánfa is more advantageous than the other pear varieties and sites.

Sour cherry production in the world is increasing gradually. Profitable production, i.e. yield, depends largely on weather conditions. If Hungary wishes to keep up with the most successful countries, attention should be paid to the weather during the dormancy period, being definitely decisive from the points of view of quality as well as quantity. In order to predict the expected risk factors, characterisation of the most important weather parameters is necessary. For that purpose, the database of the Institute of Research and Extension Service for Fruit Growing at Újfehértó Ltd. has been utilised. Records of weather conditions were collected throughout the period 1984-2005, i.e. daily minimum, maximum and mean temperatures (°C), and phenological diary of sour cherry varieties ’Újfehértói fürtös’, ’Kántorjánosi’ and ’Debreceni bôtermô’. For the future expectations study we have used the RegCM3.1 regional climate model with 10 km resolution. Data of 4 indicators have been traced: Average temperatures, Number of days without frost, Maximum length of periods without frost, Maximum length of frosty period. On the one hand, we surveyed the changes; on the other hand, estimates have been attempted for the future changes expected during the following decades.

A B S T R A C TIn this paper we outline a phenology model for estimating budbreak and full bloom starting dates of sour cherry on the effective heat sums with reasonable accuracy. With the help of RegCM3.1 model the possible trends of the phenology timing in the middle of the 21st century the shift of 12-13 days earlier budbreak and 6-7 days earlier of full bloom due to the warmer weather conditions can be clearly indicated. For the climatic characterization of sour cherry bloom period in between 1984-2010 and for the description of the expected changes in this very sensitive period of sour cherry with respect to the time slice 2021-2050, we introduce seven climatic indicators as artificial weather parameters such as the numbers of days when the temperature was under 0°C and above 10 °C, the numbers of days when there was no and more than 5 mm precipitation as well as the absolute minimum, the mean of minimum and the mean of maximum daily temperatures. We survey the changes of the indicators in the examined period and, regarding the full bloom start model results, we formulate the expectations for the future and make comparisons.