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Honeybee (Apis mellifera L.) visitation at the flowers of quince cultivars (Cydonia oblonga Mill.)
95-102.Views:185Studies were made on the bee visitation of 6 quince cultivars and on the foraging behaviour of honeybees at quince flowers for 3 consecutive years. The bee visitation was highly intense because both the plantation and its surrounding was overpopulated by honeybee colonies. Some 5.5 bee visits were counted in average at 50 opening quince flowers in 10 minutes and some 9.7 flowers were visited of the 50 ones observed meanwhile. This equals some 7 bee visits per flower per day per in good weather. Bee visitation, however, was variable and it was greatly different in the three consecutive years with fairly favourable weather. Some cultivars tended to be more and others less visited by honeybees than the others but these differences were not consequent at each occasion. No consequent relationship between the weather and the bee visitation of quince trees could be recognised. It was concluded that .other factors were responsible for the variable nature of the bee activity at quince. Most honeybees tended to collect pollen (51.6% in average for the 3 years) and usually much less gathered for nectar only (19.9%), and the rest of them were mixed behaviour foragers gathering for both (28.5%). There were some slight differences in the foraging behaviour of honeybees at some cultivars but these differences were not always consequent in consecutive years. Also the nectar production of flowers failed to affect the bee visitation and the foraging behaviour of honeybees definitely. For the variable nature of bee visitation and bee behaviour at quince flowers, supplementary pollination is needed to achieve as high set of fruits as high is required to a good crop at quince (at least 20-25% because the flower density is low of this fruit tree species). Since the intensity of bee visitation at the flowers is the only reliable estimate of the necessity of supplementary bee pollination further research is needed to explore the relationship between the number of honeybee visits and the consequent fruit set at quince.
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Review of nutritional value and putative health-effects of quince (Cydonia oblonga Mill.) fruit
29-32.Views:540Quince (Cydonia oblonga Mill.) has been long regarded to be a health-promoting fruit. Although it is mainly consumed in processed form, its relatively heat-stable polyphenolics were confirmed to be responsible for most of the beneficial effects. This review aims to show basic nutritional information on quince fruit such as carbohydrate, fibre, pectin and mineral element contents. In addition, vitamin and polyphenolic contents and composition as well as the physiological effects of quince consumption were also surveyed. Information on presumable protective effects against several diseases including infl ammation, atopic dermatitis, ulcers and cancer is summarized. Potential antibacterial effects of quince polyphenolics were also considered. Polyphenolics are supposed to be responsible for the major part of benefi cial health-effects, and phenolic compounds predominantly accumulate in peel. There exists a considerable extent of genetic variation in phytochemical composition among cultivars, which might be exploited in designing future breeding programs for quince improvement and opening new ways for health-related uses.
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Characterization of quince (Cydonia oblonga Mill.) cultivars using SSR markers developed for apple
7-10.Views:386Quince (Cydonia oblongaMill.) is a minor fruit crop, which is primarily used for marmalade, jam and sauce.Very few quince cultivars are known all over the world and in many cases similar names are used for presumably different cultivars. The aim of the present study was to evaluate and characterize the genetic diversity of 36 quince cultivars and selections with SSR markers. Seven out of 8 SSR markers designed from apple sequences could successfully yield amplification also in quince cultivars. Number of alleles per locus ranged from 2 to 3 alleles. These allele numbers are quite low when compared to apple. It is supposed to be the consequence of a genetic bottleneck. In spite of the low allele number per locus, the 36 quince cultivars formed 30 different genotypes. The ratio of homozygosity was low, which might be coupled with the self-(in)compatibility phenotype of quinces. SSR markers proved unable to differentiate putatively closely related cultivars (e.g. ‘Bereczki’ and ‘Bereczki bôtermő’). In general, the level of polymorphism among the tested quince genotypes was much restricted due to the low allele number detected. However, it must be considered that the number of analysed SSR loci is not enough high to estimate the overall heterozygosity of the quince genome. Further experiments are needed and the SSR markers proved to be a reliable and useful tool for such analyses.
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Nectar production of quince (Cydonia oblonga Mill.) cultivars
87-94.Views:374Nectar production of six quince cultivars were measured during three consecutive years. The nectar production of quince can be regarded to be small compared to other temperate zone fruit tree species since quince flowers contained 1.07 ± 0.06 mg of nectar in average. The extreme values, however, ranged between 0.1 and 7.3 mg/flower and this indicated that the nectar production was highly variable. The distribution of the nectar production was definitely skew because low values were definitely much more frequent than the highest ones. Our findings do not corroborate the earlier statements on the high sugar concentration of quince nectar. We found some 21-27% sugar in average, only. The normal distribution of the sugar concentration also indicates that the typical sugar concentration may be between 20-30%. Accordingly, the sugar concentration of quince nectar is rather low compared to other temperate zone fruit tree species (except pear). There was a significant negative correlation between the amount of nectar and its sugar concentration in quince flowers in all of the three years of the study (r= -0.51, n=37, p<0.02 in 1996, r= -0.57, n=28, p<0.1 in 1997, r= -0.35, n=9 I, p<0.001 in 1998). No definite difference was established between the nectar production of quince cultivars. Nevertheless, one cultivar tended to produce less and two other ones produced somewhat more nectar in average than the rest of the 6 cvs investigated but the extreme values of nectar production of cultivars overlapped in most cages.
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Antioxidant capacity and total polyphenolic content in quince (Cydonia oblonga Mill.) fruit
33-35.Views:293Fruits of twelve quince (Cydonia oblonga Mill.) commercial cultivars and selections were compared in the ferric reducing antioxidant power (FRAP) and total phenolic content (TPC) of intact and peeled fruits. The antioxidant capacity and total phenolic content ranged between 5.99 and 63.10 mmol AA/100 g FW, and 3.92 and 12.83 g GA/100 g FW, respectively. These ranges cover an almost 8-times variation among the tested genotypes in case of antioxidant capacity and also declares two-times variation for total polyphenolic content. Cultivars ‘Aromate’ and ‘Bereczki’ possessed the lowest antioxidant capacity and ‘Román portugál’ and ‘Bereczki’ had the lowest polyphenolic contents. In contrast, cultivars ‘Champion’ and ‘Konstantinápolyi’ possessed the highest antioxidant capacity and ‘Mezôtúri’ and ‘De Husi’ had the highest polyphenolic contents. The Pearson’s coeffi cient was relatively moderate but signifi cant (r=0.51) indicating a weak interdependence between FRAP and TPC values of quince fruits. Our results led us to the conclusion that quince might be considered as a valuable source of antioxidants and polyphenolics.
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The effect of the limitation of insect pollination period on the fruit set and yield of quince cultivars (Cydonia oblonga Mill.)
103-108.Views:307The effect of the partial and/or complete limitation of the insect (bee) pollination period was studied in three consecutive years at 6 quince cultivars. Quince is greatly sensitive to the limitation. Complete limitation of insect pollination resulted in no yield and also a partial limitation of the insect pollination period (exclusion of the bees at the first or at the second half of the blooming) depressed the final set and the yield by 60-70% at least or more, sometimes down to no yield. No real correlation was found between the mean mass of fruits and the fruit set. The mass of fruit seems to be rather a character of the cultivars. A loose but significant correlation was established between the intensity of honeybee visitation and the consequent yield of quince. As much as some 4-5 and 8-10 honeybee visits are needed a day on one flower to achieve the required optimal fruit set that has been declared to be 20-25% for quince in the literature. These are extremely high bee visitation figures, accordingly, no doubt the commercial quince plantations require much higher number of honeybee colonies than other temperate zone fruit tree species to supplementary pollination