Introduction
Besides the apple the pear is the second most significant kind of fruit in the temperate climate.
The produced varieties have a very large range of different shapes. The old varieties are kept in gene banks and in the collection of varieties, they are highly valuable and keeping them is the interest of the national economy. The preservation of the collection of varieties and gene banks is always timely. We can find the varieties of the different Hungarian regions, and the national and foreign varieties, which have been produced for a long time. In this way these gene materials are always available for improvement, they are the steady sources of both Hungarian and foreign improvement.
The classification of the varieties of pears has had a significant literature since the 1800s, which mainly deals with their morphological features and there are fewer essays which do research into the morphological features of flowers, fertility and the examination in connection with flowering.
The aim of our work is to get information about the morphological, flowering biological and fertility features of the varieties which can be found in the gene bank, and the examination of their fruit parameters, revealing the most important relationships and finding connection between the examined parameters.
The place, time and material of the examinations
The place of the experiments and observations is the pear gene bank of the Experimental Plant of the Department of Horticulture at Pannon University, Georgikon Faculty of Agriculture.
The collection of the varieties is located in the outskirts of Keszthely. The pear gene bank was set up in 1981. The varieties were planted at a row and stem space of 6.6×4 m with 2 and 4 trees
respectively. In the gene bank there are 265 pear varieties, 228 of which were involved into our examinations. The examinations were carried out continuously from 1995 to 2005.
The methods of the examinations
In the course of the examinations concerning frost resistance we collected 100 flower buds 2-4 weeks after the winter cooling down. We cut the buds with the part of the twigs belonging to them lengthwise using a scalpel and evaluated the degree of damage under the microscope.
In spring at the time of blooming we recorded the beginning of blooming, the main time of blooming and the end of blooming of each variety. As we had the data of ten years we put the varieties into blooming groups using the categories of early, mid-early, mid-late, and late blooming. We rated the intensity of blooming of each tree every year. Trees with almost no flowers got a grade one, and trees full of flowers were given a grade 5. The measurements of several years show which varieties tend to alternate and how often there are years when the tree does not have any flowers.
During the time of blooming we prepared flower morphological descriptions of each variety.
We recorded which varieties have petals with open, half-closed and closed positions and which ones have double petals. We also recorded the number and color of the anthers, the number of stigmas, the color of the petals and the number of flowers of each inflorescence.
During the time of blooming we started to examine the fertility together with the counting of the flowers. We marked parts of the branches of each tree at every point of the compass and we counted the fruit set until ripening.
From the time of ripening we carried out examinations of the fruit. We measured the diameter, the length, the weight of the fruits and we ranged them into the groups described by Mrs. Göndör according to their shapes. We counted the viable and aborted seeds in the halved pears and we calculated the the rate of viable and aborted seeds per carpel.
We compared the variants of some Hungarian regional varieties. We determined how much the variants are different and which of their features differ from each other, which of them can be regarded as taxons, and which of them are entirely different variants.
We carried out comparative examinations between the biological, morphological, and meteorological factors of the pear varieties.
The results of the examinations
During the examinations of frost resistance we examined the damage of winter frosts in 2003 when the temperature was below minus 10-15 degrees for a long time (14 nights). We observed that among the examined varieties the winter frost resistance of the Hungarian regional varieties is better than that of the foreign varieties. At the time of the blooming of pear trees, temperatures below 0 degree Celsius is not so frequent and not so low than in the case of other stone-fruits that bloom earlier. During the years of our examinations the most serious frost damage at blooming occurred in 1997.
According to the measurements we can observe that regarding cool weather during the blooming of the examined varieties the most frost resistant varieties were ‘Erzsébet királyné’
(4%), ‘Mello bárónő’, ‘Hardenpont téli vajkörte’ and ‘ Stössel tábornok’ (6%).
When we observed blooming time we recorded the rate of opened flowers daily.
If we consider the examined years altogether we can see a deviation of 30 days between the beginning of the blooming of varieties. In the 11 examined years the earliest blooming could be observed on 1st of April while the latest one was recorded on 1st of May. The beginning of the blooming of all the examined pear varieties happened on 15 April on average.
According to the average of the beginning of the blooming time we ranged the varieties into 4 groups regarding the time of blooming.
Group 1. Varieties of early blooming: from the beginning of April to 10 April.