ISHS Acta Horticulturae 732: VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems
FERTILITY OF SEEDS PRODUCING ALMOND CLONES |
| Authors: | I. Skola, Z. Erdős |
| Keywords: | Prunus amygdalus, rootstock, fertility, pollination, blooming time, frost, association of cultivars |
| Abstract:
Seed producing plantations with clonal group pollination system ensure the nurseries with seed used for sowing. The Fruit Research and Development Institute of Cegléd, Hungary has used 4 clones of almond (C.471, C.449, C.446, C.431) in a cross-pollination system. The arrangement of clones was 3:3:1:1, respectively, in the orchard, and the seeds were collected from mother plants. The most important factor for the scion producing nurseries is the uniformity of the population. The theoretical frequency of possible genotypes is basically influenced by the chance of fertility and the rate of pollinizers. In order to get a uniform population, it would be necessary each year to have an equal rate of pollinizers and the same chance of fertility. We have examined self-pollination (autogamy), open pollination and cross pollination. During the years 2000-2002, a traditional open field examination method was used by isolating flowers in pergamin bags until the end of bloom, after which the bags were removed. Before manual cross-pollination, the flowers were not emasculated. The mean blooming time of the clones, the period of blooming and the rate of flowering differed depending on the weather conditions during the three experimental years. The quantity of pollen grains was significantly different among clones. The density of flowers was also different in the isolator bags. According to the obtained results, all four clones were self-sterile. We did not find any inter-incompatibility among clones; every combination was fertile. Cross pollination was more satisfactory than open pollination, because of the unsuitable weather-conditions for bee pollination. Weather during bloom was a more significant influence on fertility than genetic determination of the clones. The germination of progeny was high enough and independent from parental effects. We have examined three characteristics of the seedlings: collar diameter, seedling height and branching. The characteristics were evaluated in comparison with the progenies resulting from open-pollination. Having examined the maternal effects, the results of progenies were the same as those of the open-pollinated ones and we found only one significant paternal inheritance in C.471 mandel clone, which resulted in dwarfing of the progenies. The results of our work show that the rate of pollinizers was variable each year, but the C.471 clone as paternal parent had a different effect for progenies. | |
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