Scientific Papers Series B Horticulture

planting scheme). The chosen shape of thecanopy was the free palmette.The soil is a calcareous chernozem, with aloamy texture and a low alkaline pH (8.2) on itsentire profile. On average, the climaticconditions were also favourable to the growthand fructification of the trees, with theexception of the years 2010, 2011 and 2012,when a strong frost occurred in January andFebruary, causing the loss of several floweringbuds. The climatic data were recorded with theaid of an automatic meteorological station, typeWatchDog, and were processed as diurnalaverages.It was found that the resistance is very differentpeach cultivars from year to year due to climatechange in recent years and the magnitude ofclimatic accidents.Determinations were carriedout in order to assess the losses of floweringbuds due to temperature variations duringwinter and the low diurnal temperatures.RESULTS AND DISCUSSIONSAlthough the south-eastern part of Romania hasbeen considered to be favourable to the cultureof peach tree, this suffered because of theclimatic variations, mainly the aggressivenessof the low temperatures in alternation with themaximum positive values. The peach treerecorded losses because of these variationswhich occurred during the dormancy period inthe climatic conditions of 2010, 2011 and2012.It was noticed that the resistance of peachtree cultivars differs from one year to anotherbecause of the climatic changes occurred in thepast years. Other factors are: the alternationbetween minimum and maximum temperaturesduring winter, which reduces the trees’resistance and last but not least, the severity ofthe climatic accidents (Figure 1).Figure 2 reveals the fact that the coldest monthin the period October 2009 – March 2010 wasJanuary 2010, when, for 10 consecutive days,the values recorded ranged between-10.1°C(January 29 th ) and-17.7°C (January 24 th and25 th ). Moreover, in the same period, thetemperatures in the valleys dropped bellow-18°C, up to-20°C (local observations). Thesevalues, together with the big diurnal differencesin temperature in the month of February causedthe loss of some flowering bud, in earlycultivars such as Springold (61%), Springcrest(59%) and Cardinal (39%).Figure 1. Aspects of the winters of 2010, 2011 and 2012with the frost on the branchesIn the October 2010-March 2011 period, thelowest temperature was recorded in January:-12°C. The lowest temperature recorded duringthis period affected Springold cultivars in 40%and Spingcrest with 38%.As can be observed in Figure2c, January wasthe coldest month, with 9 days displayingaverage diurnal values ranging between-10.2°Cand-17.6°C. These values, together with theextreme amplitudes in February (7 days withaverage diurnal values ranging from-10.4°C to-16.4°C) and 8 consecutive days of glazed frostand ice on branches caused the loss of 31%-63% of the flowering buds of all the studiedcultivars.214