BIOLOGICAL AND PRODUCTIVE PROPERTIES OF THE FORMS OF GRAPEVINE CULTIVAR TRAMINER IN THE SUBREGION OF NIŠ

Traminer is a well-known grapevine cultivar. It is thought to originate from Tramin, Italy, wherefrom it has been introduced to many European countries (France, Switzerland, Austria, Germany). Researches included two Traminer cultivar forms: White Traminer and Red Traminer. Examinations were carried out in a collection vineyard of the Viticulture and Wine Production Center of Niš. The collection vineyard was planted in 1995, with planting space of 3 x 1.2 m. Examinations took three years (2004-2006) and encompassed phenological observations, fertility, vegetative potential of a vine, resistance to Botrytis cinerea and wine quality. A detailed ampelographic description of two Traminer cultivar forms was also provided according to O.I.V. descriptors. The purpose of this paper is to determine growth, fertility, yield, and grape and wine quality of the examined Traminer cultivar forms in the viticultural subregion of Niš. According to the results obtained, the examined forms could be successfully grown in this region. Average grape yield varied depending on conditions of the particular year. White Traminer recorded higher yield, while Red Traminer recorded better quality. In addition, the best vines have been selected within the forms, and they will be used in further studies and multiplication.


Introduction
The occurrence of biotypes and forms within old grapevine cultivars is a wellknown fact (Kaserer and Regner, 2003).Traminer is a very old and widespread cultivar with many biotypes characterized by diversity of genetic and phenotypic vineyard belongs to the subregion of Niš, with prevailing moderate continental climate.The average annual air temperature is 11.8°C, and the mean temperature during growing season is 18.1°C.The absolute minimum air temperature of -18.2°C was recorded in February of the second (2005) year of examination, but it did not cause strong winterkill of buds in the examined Traminer cultivar forms.During the research period, average annual precipitation was about 750 mm, of which 422 mm fell during the growing season.The vineyard was established on the soil type cambisol.It was established in 1995, with 3 x 1.2 m planting distance, and 2,777 vines per hectare.Combined pruning, with the load of 20 buds per vine, was applied in the experiment.
Within the examined forms of Traminer cultivar, 12 vines were monitored according to RCBD method (Random Complete Block Design), with a repetition including 3 vines.Statistical data processing was carried out using following methods: variance analysis, F-test, t-test, and correlation analysis.An ampelographic description of the forms examined was made based on OIV descriptors (Anonymous, 1983), i.e. according to the Codes System stipulated by UPOV for a description of new genetic resources of grapevine.Leaf area was measured using the calculation-graphical method (Anonymous, 1983).Within each Traminer form, 15 leaves from basic shoots and 15 leaves from lateral shoots were taken.The number of leaves per vine was determined and the leaf area index (leaf area per m 2 of the vineyard area) was calculated.The pruned shoots from each vine were weighed using a scale.
Resistance to Botrytis cinerea was estimated by means of OIV descriptor, Code 459: 1 -3 very low resistance, 5 -medium resistance, 7 -9 high or very high resistance.Must quality, presented through the average content of sugar and total acid, was determined on representative samples during the vintage.Oechsle scale was used to measure sugar content, while titration with N/4 NaOH was applied in order to measure the total content of acid.Microvinification and chemical analysis of wine were carried out in the enological laboratory of the Viticulture and Wine Production Center of Niš.The quality of the wine produced was determined based on the results of the chemical analysis and organoleptic assessment made by the wine tasting commission of the Faculty of Agriculture, University of Belgrade.

Results and Discussion
Ampelographic description was carried out according to the OIV descriptor (Anonymous, 1983), i.e. according to the Codes System which stipulates UPOV for a description of new genetic resources of grapevine.
The examined Traminer forms did not show any considerable differences based on the acquired data on ampelographic and botanical description of the tip of a young shoot, a leaf, a blossom, a flower, a bunch and a mature shoot (Table 1).Table 2 presents average dates of the beginning of registered phenophases within the annual cycle of growing and development of the examined Traminer forms.Based on the results of phenological observations in the conditions of the vineyard subregion of Niš, we can draw a conclusion that between White Traminer and Red Traminer there was no difference in the dates of sap exuding, the beginning of flowering and the end of flowering, while dates of other phenophases differed by a day, except for the veraison phenophase, at which a four-day difference was registered.
Table 2. Phenological observations of the examined forms of Traminer cultivar (average, 2004-2006).The number of developed and fertile shoots considerably varied between the examined forms of Traminer cultivar (Table 3).Out of the total number of White Traminer shoots left at pruning, about 17.75 shoots, of which 15.31 fruit bearing ones, developed.As for Red Traminer, 16.94 shoots, of which 12.61 fruit bearing ones, developed out of the 20 shoots left.In the examination years, meteorological conditions considerably influenced differentiation of fertile buds and the development of fertile shoots.In both forms, there were approximately as much developed and fertile shoots per vine as in the first and the third year, i.e. considerably more than in the second year of examination.Yield parameters (yield per bud, grape yield per developed shoot, grape yield per fertile shoot, grape yield per vine, grape yield per hectare, bunch weight) varied significantly (P < 0.05) between the examined forms as well as between the examination years (Table 4).Average values of all yield parameters in White Traminer were considerably higher than in Red Traminer, excluding the bunch weight.The highest yield per vine in White Traminer (2,969 g) was in the third (2006) year, and the lowest (2,157 g) in the second (2005) examination year.Red Traminer had the highest yield per vine (2,581 g) in the first ( 2004) year, and the lowest (1,267 g) in the second (2005) year.The data obtained clearly indicated that the lowest yield in both forms was in the second year, namely much lower than in the other two years of examination.Grape yield per hectare varied in the same manner as grape yield per vine.According to grape yield per hectar, Red Traminer (5,361 kg/ha) falls within the scope of low yield (up to 6,000 kg/ha) while White Traminer (7,441 kg/ha) falls within the scope of moderate yield (6,000 -12,000 kg/ha).White Traminer, with the average number of 25 bunches per vine, produced the average bunch weight of 107.82 g.On the other hand, Red Traminer, with the average number of 18 bunches per vine recorded the bunch weight of 107.91 g.Differences in the bunch weight between the examined forms, and examination years as well, were not significant.Cindrić et al. (2000) reported the average bunch weight of the forms examined under the conditions of Fruška Gora: Red Traminer 139 g, and White Traminer 142 g.In our examinations, Traminer cultivar forms had smaller bunch weight than the one recorded by the above-mentioned authors.Bearing in mind that yield is mainly dependent on the number of bunches and the average bunch weight, in our researches the yield was more dependent on the number of bunches than on the average bunch weight.Taking into account biological features of Traminer forms, we can say that the yields during the research period were regular and low, especially in Red Traminer.
Influence of the examined forms of Traminer cultivar and meteorological conditions of the year on the vegetative potential and productivity is presented in Table 5. WPSV -weight of the pruned shoots per vine , WS -weight of a shoot, TPV -total productivity of a vine.
Pruned grapevine weight between the examined forms did not vary considerably.Red Traminer with 17 developed shoots in average recorded the pruned grapevine weight of 750.3 g, while White Traminer with 18 shoots per vine recorded the weight of 736.1 g.The highest grapevine yield was registered during the first year when the highest grape yield was registered as well, but due to advantageous meteorological conditions in this year, there was not evident a depressing influence of yield on the grapevine growth.Average vegetative potential of the forms examined was almost equalized during the second year, i.e. it was considerably lower in comparison with the first examination year.
Higher average weight of a shoot was obtained for the Red Traminer (44.7 g), as a result of less developed shoots.The total vine productivity of White Traminer (3,417 g) was significantly higher than of Red Traminer (2,681 g).If observed per examination years, the highest values of total productivity were registered in the years with the highest grape yields as well, i.e. in the first and the third year the productivity was considerably higher than in the second examination year.
To know the leaf area is essential for physiological researches, studies of lighting conditions in canopy, assessments of effects of certain cultural practices.The leaf area is closely related to the yield and quality of grapes, must and wine (Milosavljević, 1998;Williams and Martinson, 2003;Lopes and Pinto, 2005).An average leaf area did not vary significantly between Traminer cultivar forms (Table 6).A negative weak correlation (r = -0.18)was determined between the leaf area and the grape yield per vine.The forms examined did not show significant difference in leaf area index.The biggest leaf area index, in average for both forms, was measured in the first (2.68 m 2 ) and the third (2.66 m 2 ) year, and it was significantly higher when compared to the second examination year (2.19 m 2 ).Leaf area index values of White Traminer and Red Traminer were at the level given by Mozer (1971) and Csepregi (1982).A positive significant correlation (r = 0.51) was determined between the leaf area index and the grape yield.The value of 25,000 to 30,000 m 2 was given as the optimum leaf area per hectare, while the forms we examined had a leaf area under 25,000 m 2 /ha.Red Traminer showed a high level of resistance, while somewhat lower resistance level was registered in White Traminer (Table 7).The highest resistance level was registered in the first ( 2004) year (8.0), while the strongest Botrytis cinerea attack was registered in the second (2005) examination year (7.0).Data on the resistance level obtained in our researches are similar to the earlier reported data for Traminer cultivar, but there are cetrain discrepancies.Zirojević (1974) stated that Red Traminer has medium sensitivity to the Botrytis cinerea attack, while in our examinations it was classified as a highly resistant cultivar.A high content of sugar (22.39%) was registered in the must of the White Traminer form characterized by a high average yield (Table 8).Red Traminer recorded lower sugar content (20.94%).The lowest grape yield in the second year did not cause the increase of the sugar content in must.Traminer forms had a high content of acids in must (7.88 g/l in average).This indicator was especially prominent in Red Traminer with 8.15 g/l of total acids.The highest acid content in must was obtained in the second examination year (8.16 g/l).Traminer is a grapevine cultivar that produces wine which European winemakers call "the king of wine".Table 9 data indicate that the alcohol content in wine is appropriately expressed, analogously to the sugar content.A higher alcohol content was obtained in White Traminer wine (13.33%).Content of the total extract varied from 17.25 g/l in White Traminer Wine to 18.95 g/l in Red Traminer wine.Content of the total acid varied within the limits of 5.4 g/l in Red Traminer wine to 6.5 g/l in White Traminer wine.
Red Traminer wine has been awarded the average organoleptic grade of 18.44 points, which classifies it in the category of top-level white wines.Wine tasting grade awarded to White Traminer wine is 17.39 points, which classifies it as a quality wine.

Conclusion
According to the ampelographic and botanical description, between two examined Traminer grapevine forms (White Traminer and Red Traminer) were not found big differences.The dates of phenopological phases of these two forms did not differ more than one day, except the veraison phenophase at which the difference of four days was recorded.
Average values of yield parameters of the White Traminer were considerably higher than those of the Red Traminer, excluding the bunch weight.The yield per hectar was small (5,361 kg), and average (7,441 kg) in Red Traminer and White Traminer respectively.Red Traminer showed high resistance level to Botrytis cinerea, while in White Traminer resistance level was slightly weaker.
Chemical composition of wines of the examined Traminer cultivar forms showed that they had high content of alcohol and a favourable content of the total acids.Organoleptic assessment of the wine fluctuated between 17.39 points (White Traminer) and 18.44 (Red Traminer), which could be considered highly satisfactory.

Table 1 .
Ampelographic description of the Traminer forms using OIV descriptor.

Table 3 .
The number of developed and fertile shoots.

Table 4 .
Grape yield of the examined Traminer cultivar forms.

Table 5 .
Vegetative potential and productivity of examined forms of Traminer cultivar.

Table 6 .
Leaf area and leaf area index of Traminer cultivar forms.

Table 8 .
Content of sugar and total acid in must of Traminer cultivar forms.

Table 9 .
Chemical composition and organoleptic assessment of wine of the Traminer cultivar forms.