Abstract: In this study, fertilization biology of Burdur dimriti, Sariemin, Tilki kuyrugu, Razaki, Buzgulu, Siyah buzgulu and Siyah gemre grape varieties (Vitis vinifera L.) which are grown in Isparta, Turkey ecological conditions was investigated. For this purpose, rates of fruit set obtained from open pollination and isolation experiment were determined in vineyard. Furthermore, pomological analyses were done to determine the effects of experiments on fruit quality. It was determined that fruit set levels varied between 30.0 and 40.6% in open pollination, 15.0 and 34.3% in isolation experiment. In the study, Siyah dimrit, Sariemin, Tilki kuyrugu, Razaki and Siyah gemre varieties with hermaphrodite flowers were self-fertile, but Siyah buzgulu variety having hermaphrodite flower was found partially self-fertile and Burdur dimriti with hermaphrodite flowers and Buzgulu with morphological hermaphrodite-physiological female flowers were found self-unfertile.
Introduction
The low quantity and quality in viticulture is an important problem in many vineyards. The quantity and quality in viticulture relates to vine number per area and number and size of clusters and berries as well. However, these characteristics are affected by several internal and external factors such as variety, rootstock, cultural experiments and ecological conditions (Odabas, 1976). In process from creating primordial clusters to maturation of grapes, there have been many effective factors in quantity and quality. One of the fundamental factors in quantity and quality is characteristics of the fertilization biology of grape varieties.
There are many differences among the grape varieties grown in terms of areas and regions. Among these grape varieties, there may also be self-fertile, partially self-fertile or self-sterile ones. While establishing the vineyards, if there is not a good pollinezer for partially self-fertile or self-sterile varieties, it is not possible to take enough product quantity and quality. For this reason, it is necessary to determine the fertilization biology of grapes for both determining unfertile varieties and success of breeding studies. Therefore, fertilization biology of grapevine have been investigated in many studies (Fidan and Celik, 1979; Saaman et al., 1981; Bindra, 1989; Wang et al., 1993; Ebadi et al., 1995; Tsolava, 1996; Kelen et al., 1996a; Kelen et al., 1996b; Eti et al., 1998; Kimura et al., 1998; Persuric et al., 1998; Hu et al., 1999; Nesmith, 1999).
This study was carried out to determine the fertilization biology of eight grape varieties (Vitis vinifera L.) grown in Isparta, Turkey. For this reason, flowering periods of these varieties, the effects of isolation and open pollination on fruit set and quality were investigated.
Materials and Methods
This study was carried out in a twenty-year-old vineyard, trained with the middle high goblet system, in Isparta, Turkey. In this study, Burdur dimriti, Siyah dimrit, Sariemin, Tilki kuyrugu, Razaki, Siyah buzgulu and Siyah gemre and Buzgulu varieties were used as materials. This study was conducted on four healthy vines selected from per variety.
In order to determine the fruit set capacity, 25x30 cm of cloth bags were used in the isolation experiments and nothing was done for the open pollination. For both of the pollination experiments, eight clusters were chosen from each variety when there was no blooming on clusters but they were just about to bloom. The flowers on these clusters were counted and the clusters were labelled. Four of those labelled clusters were put in cloth bags while the rest of clusters were left for the open pollination. In flowering season, the clusters in cloth-bags were sometimes shaken by hands. The clusters were counted four times in twenty-day periods to determine the changes in fruit set capacity and the fifth counting was done during the harvest. Statistical analysis was performed on angle values of percentages and the averages were compared according to the Duncan’s Multiple Range Test. The real numbers were used in the tables of articles.
In order to determine the effects of pollination experiment on fruit quality, the berry width and length (mm), berry weight (g), seed numbers (n), seed weight (mg), TSS (Total Soluble Solid) (%) and titratable acidity capacity (g L-1) were determined. The experiment was established according to the randomized design with four replication and 50 berries in each replication. The data obtained were analysed statistically and the differences were evaluated according to the Duncan’s Multiple Range Test.
Results
Phenological Observations: The flowering and harvest date were varied for varieties. The earliest flowering date was the first of June for the Burdur dimriti and the latest was the sixteenth of June for the Buzgulu. The shortest flowering period in varieties was thirteen days in the Siyah dimrit and the longest period was seventeen days in the Burdur dimriti (Table 1).
The Effects of the Open Pollination and Isolation Experiment on Fruit Set: In the counting 20 days after flowering, it was found that the highest fruit set were 78.6 and 72.0%, in the Burdur dimriti and Sariemin, respectively in the open pollination. The lowest fruit set levels were determined 44.3, 48.0 and 51.3% in the Buzgulu, Razaki and Siyah buzgulu, respectively in the isolation experiment. In the counting 40 days after flowering, the highest fruit set were found 52.0, 51.6, 51.3 and 49.6% in the Siyah gemre, Buzgulu, Siyah buzgulu and Razaki, respectively in the open pollination and 49.3% in the Sariemin in the isolation experiment. The lowest fruit set were determined 31.6% and 33.6% in the Burdur dimriti and Siyah buzgulu, respectively in the isolation experiment. In the counting 60 days after flowering, the highest fruit set rates were found 46.3, 42.3 and 42.3%, in the Buzgulu, Razaki and Siyah gemre, respectively in the open pollination. The lowest fruit set level was determined 23.3% in the Burdur dimriti in the isolation experiment. At harvest time, the fruit set of varieties changed between 30.0 and 40.6% in the open pollination and 15.0 and 34.3% in the isolation experiment.
| Table 1: | Flower types, flowering season and harvest date of the grape varieties (1999) |
| * hermaphrodite** morphological hermaphrodite-physiological female | |
| Table 2: | Fruit set levels in the pollination experiments (%) |
| *Mean separation within columns by Duncan Multiple Range Test, p<0.05 | |
| Table 3: | The effects of pollination experiments on berry width, length and weight |
| *Mean separation within columns by Duncan Multiple Range Test, p<0.05 | |
| Table 4: | The effects of pollination experiments on seed number, seed weight, TSS and acidity |
| *Mean separation within columns by Duncan Multiple Range Test, p<0.05 | |
The highest fruit set rates were found 40.6, 38.0, 36.6, 36.3, 34.3 and 32.3% in the Buzgulu, Siyah buzgulu, Siyah gemre, Razaki, Tilki kuyrugu and Burdur dimriti, respectively in the open pollination and 34.3, 33.0 and 30.6% in the Tilki kuyrugu, Razaki and Siyah gemre, respectively in the isolation experiment. The lowest fruit set level was found 15.0% in the Burdur dimriti in the isolation experiment (Table 2). In the isolation experiment, it was determined that most of berries of the Buzgulu and Burdur dimriti varieties were set parthenocarpic, but berries of the other varieties were set normally.
The Effects of the Open Pollination and Isolation Experiment on Fruit Quality: The highest berry widths were found 19.70, 18.36, 18.36 and 18.28 mm in the Razaki, Siyah gemre, Sariemin and Tilki kuyrugu, respectively in the isolation experiment and 18.73 mm in the Razaki in the open pollination. The lowest berry width was determined 6.16 mm in the Buzgulu in the isolation experiment. The highest berry length were determined in the Tilki kuyrugu and Razaki with 24.77 mm and 23.81 mm, respectively in the isolation experiment and in the Tilki kuyrugu with 23.66 mm in the open pollination. The lowest berry length was found in the Buzgulu with 8.45 mm in the isolation experiment. The highest berry weight were determined in the Razaki and Tilki kuyrugu with 5.43 g and 4.90 g, respectively in the isolation experiment and in the Razaki with 5.08 g in the open pollination. The highest and the lowest seed number were found in the Siyah buzgulu with 2.61 and in the Buzgulu with 0.02, respectively in the isolation experiment. The highest seed weight were determined 45.2 mg and 43.9 mg in the Siyah gemre and Razaki, respectively in the open pollination and 44.5 mg and 42.3 mg in the Razaki and Siyah gemre, respectively in the isolation experiment. The highest TSS were found in the Siyah dimrit with 15.8% and 15.5% in the open pollination and in the isolation experiment, respectively. The highest acidity were determined in the Razaki and Tilki kuyrugu with 8.61 and 6.87 g L-1, respectively in the open pollination and in the Razaki, Siyah dimrit and Siyah gemre with 8.49, 6.78 and 6.76 g L-1, respectively in the isolation experiment.
Discussion
In the study, it was determined that fruit set levels varied with regard to variety and pollination experiment. Similar conclusions were drawn in the studies of Wang et al. (1993); Kelen (1996a); Tsolova (1996); Kimura et al. (1998); Persuric et al. (1998); Nesmith (1999). Fruit set levels were found 30.0 – 40.6% in the open pollination and 15.0 – 34.3% in the isolation experiment. In the Burdur dimriti and Buzgulu, fruit set levels were considerably decreased and berries were mostly set parthenocarpic in the isolation experiment, but berries were set normally in the open pollination. Fruit set rates of the Burdur dimriti and Buzgulu were found 32.3% and 40.6% in the open pollination and 15.0% and 29.6% in the isolation experiment. This case shows that those varieties are self-unfertile. In addition, Fruit set level of Siyah buzgulu was clearly decreased in the isolation experiment, but berries set normally. Siyah buzgulu may be accepted partially self-fertile.
After corolla fall, it was determined that there was a general heavy shedding of undeveloped fruitlets of varieties. Fruit drops were heavily in the first counting. These are presumed to be mostly from unfertilized flowers. Although later drops were decreased considerably, those drops were continued to harvest date. It is thought that those drops must be affected such as insufficient of fertilization and nutrition, physiological causes, growth regulators factors and environmental factors. The selective shedding of same fruits and the retention of others is, at present, not understood (Westwood, 1995).
Fruit quality with regard pollination experiment were not changed in varieties except from Burdur dimriti and Buzgulu. In isolation experiment, berry width, length, weight and seed number of Burdur dimriti and Buzgulu were decreased considerably. It is thought that this decrease in those varieties took from parhenocarpic set of berries.
In the open pollination experiment, the berry width of the Burdur dimriti and Buzgulu varieties were 18.04 and 17.83 mm, respectively while they were 9.02 and 6.16 mm, respectively in the isolation experiment. In the open pollination experiment, the berry length of the Burdur dimriti and Buzgulu were 21.19 and 21.63 mm, respectively while they were 12.62 and 8.45 mm, respectively in the isolation experiment. In the isolation experiment, the berry weights of these varieties were 1.41 and 0.49 g, respectively while they were 4.13 and 4.07 g in the open pollination experiment. The seed numbers of the Burdur dimriti and Buzgulu were 1.32 and 2.00 in the open pollination experiment while they were 0.61 and 0.02 in the isolation experiment (Table 3 and 4). However, there were no any statistically differences between the isolation and open pollination experiments in terms of seed weight, TSS and acidity in Burdur dimriti and Buzgulu. Furthermore, it was determined that there were no any statistically differences between isolation and pollination experiment in the other varieties in terms of fruit quality characteristics.
Results obtained from this research summarised as follows;
1.Among grape varieties was determined 15 and 35 day differences in respect of starting of flowering and harvest date, respectively.
2.Fruit set levels varied 30.0 – 40.6% and 15.0 – 34.3% in open pollination and isolation experiment, respectively.
3.Burdur dimriti with hermaphrodite flowers and Buzgulu with morphological hermaphrodite-physiological female flowers were found self-unfertile, Siyah buzgulu variety having hermaphrodite flower was found relatively self-fertile, but the others varieties were determined self-fertile with regard to fruit set and quality.
4.Berries of Buzgulu and Burdur dimriti were mostly set parthenocarpic in isolation experiment.
5.In isolation experiment, berry width, length, weight and seed number of Burdur dimriti and Buzgulu were decreased considerably, however there were not any statistically differences in terms of seed weight, TSS and acidity.
6.Any differences between open pollination and isolation experiment was not found in respect of fruit quality in the Siyah dimrit, Sariemin, Tilki kuyrugu, Razaki, Siyah buzgulu and Siyah gemre varieties.
7. In order to have berry at adequate amount and quality from Buzgulu and Burdur dimriti varieties, it is necessary to determine appropriate pollinizers and to pay attention to these results while establishing vineyard.