Self fertility of pear varieties conditioned by natural self pollination (autogamy)

Abstract

Authors studied the autofertility depending on natural self pollination (autogamy) in 59 pear cultivars during 4 seasons at three locations with different ecological conditions (Helvetia, Kecskemet-Kisfai, Keszthely). The aim of the experiments was to determine the autogamous tendencies of varieties hitherto unexplored in the Hungarien gene bank, or to check data found in the literature. A total of 42616 isolated pear flowers produced 1.2% fruits with at least one viable seed in each. The 59 varieties observed did not set fruit by autogamy on either of the three sites during the four years of the study. The triploid (3n=51) varieties were entirely self-sterile. According to the highest autogamous fruit set, during the experimental period, the varieties have been assigned to four groups: (1) Entirely auto-incompatible (0% fruit set), (2) auto-incompatible (0.1 to 0.9%), slightly self fertile (1.1 to 5%) and (4) self fertile (5.1 to 10%). According to the number of viable seeds per fruit resulting from autogamy, the varieties are assigned to three groups as (1) low seed content (less than 3 seeds per fruit), medium (3.1 to 5) and (3) high (more than 5 seeds). Thus, the assessment of the number of seeds per fruit resulting from autogamy is indispensable as a proof of the absence of parthenocarpy.

Influence of Reproductive Impairment of Most Developed Flowers on Fruit Set and Fruit Quality in Pear

“…This weak set and seed content had allowed that partenocarpic fruit, though less competitive, remained until harvest in all treatments and control. In the highly parthenocarpic 'Conference' (Nyeki et al, 1998(Nyeki et al, , 2000, unseeded fruit only appeared in SR7 treatments, because the presence of highly seeded fruit in open pollinated clusters reduced the ability of the unpollinated fl owers to set (Goldwin, 1984).…”

“…'Blanquilla', despite being one of the leading Spanish cultivars, has an erratic and often low productivity due to its short effective pollination period (Sanzol et al, 2003), low parthenocarpic strength and low self-fertility (Cambra and Herrero, 1978;Sanzol, 2001) and lack of suitable pollenizers of commercial interest (Sanzol andHerrero, 2002, 2003). 'Conference' shows the opposite productive features as it has a long effective pollination period, it is highly parthenocarpic, self-fertile, and with many suitable pollenizers (Nyeki et al, 1994(Nyeki et al, , 1998(Nyeki et al, , 2000.…”