Self-incompatibility is common in apricot (Prunus armeniaca L.) cultivars of Central Asian and Irano-Caucasian ecogeographical groups, while cultivars of European group are traditionally considered as self-compatible. However, the number of known self-incompatible cultivars of the European group has increased rapidly over the last two decades. This can be explained by using Asian or North American self-incompatible cultivars in breeding programs that aim to create new genotypes with the traits including: Plum Pox Virus resistance, frost tolerance, increase of the sugar content or extending the harvest time. In this work self-(in)compatibility was tested in 38 apricot cultivars. Pollentube growth in pistils pollinated in laboratory was analysed using fluorescence microscopy. Cultivars were considered self-compatible if at least one pollen tube reached the ovary in the majority of pistils. In self-incompatible cultivars growth of pollen tubes in the style of pistil stopped along with formation of characteristic swellings. Of the examined cultivars, 17 were self-compatible, and 21 were self-incompatible.
The pattern of electric signals accompanying compatible and incompatible pollination were studied in pistils of petunia (Petunia hybrida L.) and rape (Brassica napus L). Electric potential was recorded for 4–7 hours with non-polarizable Ag/AgCl electrodes implanted into the ovary and beneath the sigma. At the end of measurements, pistils were fixed and the growth of pollen tubes was analyzed under a fluorescent microscope. Action potentials appeared in both species. In rape the potential dropped by 10 mV for few minutes after pollination regardless of the compatibility of the cross. In this species, during compatible pollination action potentials with amplitudes of 15–20 mV were recorded up to one hour after pollination. They were followed by a long lasting decrease of the potential by 10 to 50 mV. Contrary, after the self-incompatible pollination, action potentials were rare and of lower amplitudes and the potential gradually raised in comparison to the initial level. During the first hour after the compatible pollination of Petunia hybrida series of action potentials with amplitudes reaching 10–20 mV were recorded. At the time corresponding to the pollen tubes entrance to the transmitting tissue of the style, action potentials reaching up to 40 mV were followed by a steady decrease of the potential. The electric signals traveled along the style with velocity of 25 mm/s. Incompatible pollination in petunia resulted only in minor oscillation and gradual increase of the potential up to 100 mV in comparison to the initial level. The present investigation demonstrated that each phase of pollen-stigma recognition events, germination and growth of pollen tubes within the style have its characteristic pattern of electric changes which was species specific and depended on compatibility of the cross.
A common wheat (Triticum aestivum L.) mutation that produces 3 pistils (TP) per floret may result in formation of up to 3 kernels per floret. The TP trait may be important for increasing the number of grains per spike and for improving the yield potential through breeding. This trait is determined by the dominant Pis1 gene. Genetic mapping of Pisl involved 234 microsatellite markers and bulk segregant analysis of a cross of the TP line with Novosibirskaya 67. The Pis1 gene is located on chromosome 2DL, between markers Xgwm539 and Xgwm349. This result does not agree with a previously published localization of the Pis1 gene on chromosome 5B. The possible importance of TP wheat as an alternative genetic resource is discussed.