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The mechanisms underlying plant species distribution and abundance have been long studied in ecology. However, the role of heterospecific pollen interference in shaping these patterns needs more attention. Species distribution and abundance are important factors determining whether a species is endangered or not; thus, understanding the impact of heterospecific pollen interference on rare species could help to inform conservation strategies aimed at preserving plant communities. In this study, we conducted a multispecies experiment using eight co‐occurring and co‐flowering plant species with varying rarity levels in Switzerland. We performed cross‐pollinations by hand between nearly all species pairs and measured seed set (whether a flower produces seed) and seed number (number of seeds per flower) as outcomes. We looked at the effects of rarity status, self‐compatibility, and recipient‐donor relatedness on heterospecific pollen interference. Contrary to expectations, neither seed set nor seed number were affected by heterospecific pollen deposition. Self‐compatible species had a higher seed set probability, but this was independent from species rarity. In our study setting, heterospecific pollen interference seems to have only minor effects on seed set and seed number, and consequently on recruitment. Thus, heterospecific pollen interference seems to play only a minor role in shaping plant species distribution and abundance. Nevertheless, the higher impact of heterospecific pollen deposition on rare and closely related species, as well as the importance of conspecific pollen loss, might need further investigation for both in situ and ex‐situ conservation strategies. [ABSTRACT FROM AUTHOR]

ABSTRACT The mechanisms underlying plant species distribution and abundance have been long studied in ecology. However, the role of heterospecific pollen interference in shaping these patterns needs more attention. Species distribution and abundance are important factors determining whether a species is endangered or not; thus, understanding the impact of heterospecific pollen interference on rare species could help to inform conservation strategies aimed at preserving plant communities. In this study, we conducted a multispecies experiment using eight co‐occurring and co‐flowering plant species with varying rarity levels in Switzerland. We performed cross‐pollinations by hand between nearly all species pairs and measured seed set (whether a flower produces seed) and seed number (number of seeds per flower) as outcomes. We looked at the effects of rarity status, self‐compatibility, and recipient‐donor relatedness on heterospecific pollen interference. Contrary to expectations, neither seed set nor seed number were affected by heterospecific pollen deposition. Self‐compatible species had a higher seed set probability, but this was independent from species rarity. In our study setting, heterospecific pollen interference seems to have only minor effects on seed set and seed number, and consequently on recruitment. Thus, heterospecific pollen interference seems to play only a minor role in shaping plant species distribution and abundance. Nevertheless, the higher impact of heterospecific pollen deposition on rare and closely related species, as well as the importance of conspecific pollen loss, might need further investigation for both in situ and ex‐situ conservation strategies.

The cultivated pear is an economically important fruit tree species of genus Pyrus in which often gametophytic self-incompatibility occurs. Therefore, this species need to be pollinated by cross-compatible cultivars that bloom in the same time. Selection of appropriate pollinizers for pear cultivars is very important to produce commercial yield. ‘Sebri’, ‘ Shahmiveh’ and ‘Natanzi’ are the best commercial cultivars in Iran, but the lack of a suitable source of pollen can reduce productivity. In order to select the most suitable pollinizer for these pear cvs, an experiment was conducted in which they were considered as pollen recipients and ‘Coscia’, ‘Bartlett’ and ‘Sardroud’ along with ‘Sebri’, ‘Shahmiveh’ and ‘Natanzi’ were evaluated as pollen donors. This research was conducted as a factorial experiment in randomized complete block design for four years. Recipient and donor cultivars had almost overlapping flowering time. The flower buds on selected branches were emasculated at balloon stage and then were counted and isolated with cotton tissue bags. Pollen grains of these pollinizers were collected in the laboratory. Isolation bags were taken off from the branches and emasculated flowers were pollinated with pollen grains of listed pollinizers during receptibility of stigma. The number of pollinated flowers was counted, and branches were covered again with the bags. The results showed that for ‘Sebri’ the best pollinizer was ‘Coscia’ with 5.7% fruit set, for ‘Shahmiveh’ ‘Bartlett’ cv. with 5.8% of fruit set and for ‘Natanzi’, ‘Shahmiveh’ with 5.5% of fruit set.

Abstract A major challenge in sugarcane breeding program is the obtaining of enough number of seeds (caryopses) for the development of new improved cultivars. Genotypes differ in their function as pollen recipient and pollen donor, which also affect the seed performance. Thus, the aim of this study was to verify the production and performance of sugarcane seeds from different hybridizations involving RB92579 as pollen recipient and pollen donor. Twelve bi-parental crossings were carried out involving RB92579 and other different genotypes randomly chosen. Seed production potential was evaluated by percentage of fertile spikelets and caryopsis fresh weight. The seed physiological potential was determined by evaluating germination and vigor (index of germination rate, number of normal seedlings per gram of fuzz, and seedling dry weight). The results showed better performance for RB92579 as pollen donor for all characteristics studied. Therefore, RB92579 sugarcane cultivar should be used as pollen donor during hybridizations, condition that permits a greater production and physiological performance of seeds for the sugarcane breeding programs.