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Laboratory and orchard tests have shown that the apricot (Prunus armeniaca L.) cultivars `Hargrand', `Goldrich', and `Lambertin-1' are cross-incompatible. All three cultivars are from North American breeding programs and have `Perfection' as a common ancestor. In orchard tests, compatible pollinations resulted in 19% to 74% fruit set, while incompatible pollinations resulted in <2% fruit set. Microscopic examination showed that, in incompatible pollinations, pollen tube growth was arrested in the style, most frequently in its third quarter, and that the ovary was never reached. It is proposed that self-incompatibility in apricot is of the gametophytic type, controlled by one S-locus with multiple alleles, and that these three cultivars are S1S2.
Eight apricot (Prunus armeniaca L.) cultivars were self- and cross-pollinated to determine pollen compatibility. Pollen tube growth in the laboratory and the percentage of fruit set in the orchard were evaluated. The results confirmed that `Moniqui Fino' and `Velázquez Tardío' are self-incompatible and established that `Gitano', `Pepito del Cura', and `Velázquez Fino' are also self-incompatible. No cross-incompatibility was found in the 25 cross-combinations.
In almond [Prunus dulcis (Mill.) D.A. Webb], a high flower density and fruit set rate is important, because yield increases with higher fruit set ratio. Furthermore, because the ovule of some cultivars mature at anthesis, rapid pollination and pollen tube growth along the style are essential to ensure fertilization of a viable ovule. In this work, we studied the effective pollination period (EPP) of four almond cultivars of different bloom time by studying pollen tube growth and fruit set. EPP in almond was longer than in other fruit trees, and its duration was determined by stigma receptivity, which decreased with high temperature. An acceptable fruit set for all cultivars was obtained following pollination from day 0 to day 4 after emasculation.
Apricot (Prunus armeniaca L. cv.'Helena') shoots grown on a proliferation medium containing 3% sucrose, 0.4 mg·L–1 benzyladenine (BA), and 0.04 mg·L–1 indolebutyric acid (IBA) and solidified with 0.6% agar were stored at three different temperatures in the dark for up to 24 weeks. All shoots remained viable for 24 weeks when stored at 3 °C, while at 14 °C the percentage of survival decreased quickly after 12 weeks of storage. At 7 °C, percentage of survival started to decline after 18 weeks of storage. Shoots stored at 3 °C had the highest regeneration rates and shoot lengths following transfer to standard proliferation conditions. This temperature also had a beneficial effect on shoot proliferation during the first 12 to 18 weeks of the experiment.