7/31/2019 Behaviour of apple cultivars under a high radiation and temperature regime of Western Plain in Albania

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Agricultural University of Tirana, Faculty of Agriculture & Environment,Department of Horticulture

Address: Koder-Kamez, Tirana, Albania www.ubt.edu.al

ehaviour of apple cultivars under a high radiation and temperature regime ofWestern Plain in Albania

Kullaj1, H. Domi2, T. Spahiu1 and F. Thomaj1

p. Horticulture, Faculty of Agriculture and Environment, Agricultural University of Tirana, Kodr-Kamz, 1010, Tirana, Albania Tel: +355684096186 Email: ekullaj@ubt.edu.alDAD, Tirana, Albania

IntroductionApple is the most important fruit species cultivated in Al-bania. To benefit from the advantages of earliness andvicinity with the markets of main cities, there is a growingtrend of cultivating it in the Western Plain, outside of itstypical and optimal areal of cultivation, the Central- andNorth-Eastern part of the country. The main cultivar inthe Western Plain is Golden Delicious (GD) on M9 (EMLA).Other alternative cultivars are Gala (GL), Pink Lady (PL)and Red Delicious (RD). The object of this study was toassess the behaviour of these cultivars under a cultivation

regime with high radiation and temperatures.

Material and MethodsThe study was conducted during 2011 on a commercialorchard of 2.5 ha, central leader system, on the 6th year,in the area of Lushnja, one of the hottest spots in Albania,with an heliothermic index HI of 2548 (Figure 1). Sap flowsensors (SF) EMS 62 (EMS Brno, CZ), based on THB (tissueheat balance) method, were installed on shoots (10 12mm) on 5 trees for each cultivar, measuring sap flow everyminute from 7th 30th of July (Figure 2). To assess the level of correlation between the sap flowof shoots and that of the entire tree, an EMS 51 sensor was placed on the trunk of a tree of cv.Golden Delicious (Figura 3). In the same tree, two dendrometers measured the trunk d iameter

variation (TDV), at 20 cm from soil and at the centralleader (2.4 m) (Figure 4). Both SF and TDV are impor-tant for irrigation decision-making. Gypsum blockssensors were used to measure SWP at two differ-ent depths, 10 and 20 cm respectively. A portablemeteorological station (Minikin RTHi) measured theglobal radiation, temperature and relative humidity.Biometric measurements of canopy elements were

also measured and analysed.

Results and DiscussionAnalysis of biometric measurements showed that

after 6 years from the planting, differences in de-velopment of rootstock/scion between the threecultivars under study are minor. Affinity indices var-ied from 0.55 for PL/M9, 0.61 for GD/M9 to 0.63RD/M9, within the acceptable limits for clonal root-stocks and mainly for M9 (0.6), showing only a par-tial incompatibility between the two components, whith effects on the modification of othercanopy elements, shoots of different categories, as well as on the vegetation and production.The same was also observed for the diameter of the main branches but without significant dif-ferences between cvs (Table 1).

Pink Lady had a higher vegetative growth, with fewer fruiting shoots. Interesting to findwas that RD which is known for its reduced growth, under a high radiation and temperatureregime had more vegetative shoots than GD and less than PL. It had less bourses and brindles.In other conditions, on the same rootstock (M9), RD has a reduced vegetative growth and high

reproductive growth.

Table 1: Biometric measurements of canopy elements

Cultivar

Diameter (mm)Affinity

index

Number of shoots Woodybranches

length (cm)

Branchdiameter

(mm)

Fruits

formedrootstock scion Spurs Bourses Brindle Woody

Gold. Del. 42.5 25.8 0.61 59 12 50 12 483 15.4 39.8Red Delic. 36.9 23.2 0.63 47 14 31 14 600 16.4 20.8Pink Lady 47.4 26.0 0.55 34 16 45 16 660 15.5 27.6

Although with a higher diameter of main branches, RD forms more vegetative shoots and less-er fruit sets (20.8 fruits/branch). Correlation between the fruiting shoots diameter and fruits setis interesting, with RD forming more stronger branches with lesser fruits.

Maximum values of evapotranspiration varied between 0,8 0,9 mm/h during the entire meas-urement period (Figure 5). SF values for RD had an average of 0,863 kg/h with maximum 3,599;those of cv. GD had an average of 0,816 kg/h with maximum 3.596 kg/h while those of cv. PL

had an average of 0.353 kg/h with maximum 1.831 (Figure 5).

Beside these differences, SF values were strongly correlated with global radiation and VPD(Figure 5). The trunk sensor values (SF Golden Delicious trunk) integrated well the transpirationof the entire tree and were correlated with the values of shoots.

It seems clearly that RD and somehow GD, due to their vigorous growth, which was shownalso by the biometric measurements, have high levels of transpiration. The comparison of SFvalues under low and high SWP showed that Pink Lady on M9 is more sensitive to soil water

availability (Figure 6).

ConclusionsThe result show significant variation between cultivars in their sensitivity to low soil water po-tential which is due to changes in vegetative/fruiting shoots. Both sap flow and TDV prove tobe good plant-based water stress indicators. Pink Lady is more sensitive to soil water availabil-ity.

Fig. 1. Map of heliothermal index (HI)showing orchard location (black dot)

Fig. 2. Sap flow sensors installed on apple branches

Fig. 3. Sap flow sensors on apple trunk

Fig. 4. Dendrometer on apple leader

Fig. 5. Relationship between evapotranspiration (ET), vapor pressure deficit (VPD) and average sapflow values of the three cultivars under study

Poster presented at the7th International Symposium on Irrigation of Horticultural Crops

Geisenheim, Germany 16 - 20 July 2012 www.irrigation2012.de

Fig. 6. Relationship between soil water potential (SWP) measured at two depths (10 and 20 cm) andaverage trunk diameter variation (TDV), for GD measured at trunk (30 cm from soil level) whilst forPink Lady at the leader, 250 cm from soil level)

Fig. 7. Daily pattern of sap flow in two typical days with high SWP (July, 26th) and low SWP (july,27th) after the irrigation