SELF FERTILITY OF PEAR VARIETIES CONDITIONED BY NATURAL SELF POLLINATION (AUTOGAMY)

Authors studied autofertility depending on natural self-pollination (autogamy) in 59 pear cv. during 4 seasons at 3 locations with different ecological conditions (Helvécia, Kecskemét-Kisfái, Keszthely). The aim of the experiments was to determine the autogamous tendencies of varieties hitherto unexplored in the Hungarian gene bank, or to check data found in the literature.
A total of 42 616 isolated pear flowers produced 1.2% fruits with 1 viable seed in each.
The 59 varieties observed did not set fruit by autogamy on none of the 3 sites during the 4 years of the study.
The triploid (3n=51) varieties were entirely self-sterile.
According to the highest autogamous fruit set, during the experimental period, varieties were assigned to 4 groups: (1) Entirely auto-incompatible (0% fruit set), (2) auto-incompatible (0.1–0.9 %), (3) Slightly self-fertile (1–4 %). There were varieties with the old pomological assortment which are reasonably self fertile at two locations: Hardenpont, Bergamotte d Esperen and some Hungarian local varieties: Arabitka, Buzás körte.
In the gene bank collection of Keszthely, 3 of the Hungarian local varieties (Csákvári nyári körte, Köcsög körte, Lõrinc kovács) proved their tendency to self-fertility in all three seasons studied.
None of the 89 pear varieties was regularly self fertile at all locations and seasons.
Consequently, the great majority of pear cultivars are considered to be entirely self-incompatible, or their fertility is very low and variable seasonally.
The latter type is practically self-incompatible too; thus cross-pollination has to be secured by mixed planting with appropriate pollinizer varieties.
Self-sterility is a specific, genetically fixed trait of pears.
Nevertheless, locality and season may modify the rate of self-fertility, which is regular and never exceeds 2 % in Hungary.
Each time, at each location, 50–250 flower buds /variety were isolated.
The tendency of autofertility is expressed by the ratio of the number of ripe fruits/ buds isolated.
No artificial selfing has been attempted; moreover, the number of viable seeds/fruit was also recorded.
The aim of the study was to assess autofertility in the pomological assortment and gene bank of Hungarian local varieties and old items. (1) did not set fruit at all (0% = fully auto incompatibility), (2) auto incompatible (0.1 – 1%) set fruit which were either (a) entirely seedless (parthenocarpic), or (b) the seeds were empty or flat without any viable germ, or (c) some viable seeds developed at a low rate (0.5–2 %) in addition to empty seeds.

VII International Symposium on Pear Growing

J. Nyéki, A. Porpáczy, M. Soltész, Z. Szabó, J. Iváncsics

https://doi.org/10.17660/ActaHortic.1998.475.53