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ŠUMARSKI LIST 7-8/2014 str. 30     <-- 30 -->        PDF

physiological parameters in wild cherry families. Families are separated by the first canonical axis (CD1) which describes 82% of variability (Table 4). According to this axis, there is a clear separation of Family 11 and Family 13 (locality Jamena) from the rest of families, mainly based on the values of water use efficiency (Table 4; Figure 2). WUE is important parameter in identification of families and genotypes adapted to water stress, as the optimization of carbon assimilation and minimization of water losses has been described as an adaptive trait (Ehleringer 1993). Plants could achieve high WUE through lower transpiration or high net photosynthesis, or both (Rouhi et al. 2007). In the present study, the highest WUE was registered in families 11 and 13, which had the highest net photosynthesis rate, as well as the lowest intensity of transpiration. Maintaining a high level of WUE plants show a specific water-saving strategy that allows them avoidance of larger water losses and moderates water absorption, which is the advantage in prolonged drought periods (Mészáros et al. 2007). Performance of the Family 7 for water use efficiency was poor in comparison to other families in this study (Table 2). This family characterized by the lowest rate of net photosynthesis and the highest transpiration rate. This kind of water-use strategy permits absorption of water from the soil at the expense of a larger loss of water through transpiration. However, such strategy cannot be sufficient in long-lasting drought periods (Stojnić et al. 2012). Second axis (CD2) describes another 14% of variability. Separation of families by the second axis (CD2) is mostly based on the absolute values of standardized coefficient for net photosynthesis (–1.656) and stomatal conductance (1.248). A and gs are frequently used in selection, as the growth and biomass production of plants are related to gas exchange parameters. Also, these parameters could be efficiently used in breeding, as the relationship between water stress, stomatal conductance and photosynthesis is important aspect of drought stress tolerance (Dickson & Tomlinson, 1996).
presence of differences in regards of E, gs and WUE indicate the possibility of choosing the best wild cherry (Prunus avium L.) families for a breeding program in the climate conditions of Vojvodina province. Due to the negligible environmental differences within the nursery trial, observed variations in stomatal conductance, transpiration and water use efficiency (WUE) could be linked to genetic differences among the investigated families. Canonical discriminant analysis revealed that parameter with the highest discriminatory capacity was water use efficiency. Based on these results it seems that Family 11 and Family 13 have the highest potential due to the highest rates of net photosynthesis, stomatal conductance and water use efficiency. In order to get more precise information about growth potential and adaptability of wild cherry families in Serbia it is necessary to