Effect of heterospecific pollen deposition on pollen tube growth depends on the phylogenetic relatedness between donor and recipient

Co-flowering plant species may interact via pollinators leading to heterospecific pollen transfer with consequences for plant reproduction. What determines the severity of heterospecific pollen effect on conspecific pollen performance is unclear, but it may depend on the phylogenetic relatedness of the interactors (pollen donors and recipient). The heterospecific pollen effect might also depend on the extent to which plants are exposed to heterospecific pollen over ecological or evolutionary timescales. For instance, generalist-pollinated plant species might tolerate heterospecific pollen more than specialists. Here, we tested whether heterospecific pollen effects are stronger between closely related species than phylogenetically distant ones in a tropical highland community. Then, based on these results, we determined whether responses to heterospecific pollen were stronger in generalized vs. specialized plant species. We applied heterospecific pollen from close (congeneric) or distant (different families) donors alone or with conspecific pollen on stigmas of three recipient species (one generalist, Sisyrinchium wettsteinii; and two specialists, Fuchsia campos-portoi and Fuchsia regia) and scored pollen tube performance in styles. In all species, pollen from closely related donors grew pollen tubes to the base of the style indicating a high potential to interfere with seed set. Conversely, distantly related heterospecific pollen had no effect on either specialist Fuchsia species, whereas enhanced performance of conspecific pollen was observed in generalist S. wettsteinii. The strong effect of phylogenetic relatedness of donor and recipient might have obscured the role of pollination specialization, at least for the three species examined here. Therefore, phylogenetic relatedness mediated the effect of heterospecific pollen on post-pollination success, with possible consequences for reproductive trait evolution and community assembly for further studies to explore.

Pollen effect (xenia) for evaluating breeding materials in maize

Pollen effect (xenia) plays an important role in modifying biochemical constituents of maize (Zea mays L.) kernels. The objectives of this study were to i) evaluate the effect of filial generations on certain genetic estimations; ii) compare general (GCA) and specific combining ability (SCA) effects obtained from Griffing?s diallel analyses between parental (F0) and F1 generations; iii) determine the relationships between pollen effect and genetic estimations; and iv) examine the possible utility of pollen effect for improving kernel-quality traits (protein and oil contents). We conducted two experiments (F0 in 2011 and F1 in 2013) and examined kernel protein and oil contents. Individual pollen effects (IPE) and specific individual pollen effects (SIPE) were computed. The results showed that entries (E) and filial generations (G) and E ? G interaction variances were significant for both protein and oil contents, whereas changes in genetic estimates between generations were highly variable. The signs and magnitudes of GCA effects were similar and highly correlated (r > 0.80) between F0 and F1 generations for all four diallel methods. In addition, GCA effects were highly correlated with IPE estimates for all four diallel methods. Specific combining ability (SCA) estimates between F0 and F1 generations were moderately correlated (r = 0.50) in Method IV for oil and highly negatively correlated (r = -1.00) in Method III for protein content. Heterosis analyses showed that hybrids could not be evaluated on the basis of the F0 generation to predict their F1 performances. Individual pollen effects between generations showed higher correlation for protein content (r = 1.00) than for oil content (r = 0.40). Specific individual pollen effects of parents were also slightly higher for protein content (r = 0.74) than for oil content (r = 0.62). We concluded that the direct or indirect utilization of pollen effect (xenia) was possible for parental evaluation but not suitable for hybrid evaluation for kernel oil and protein contents.

Metaxenic pollen effect of scab resistant apple cultivars on the fruit of apple

As a part of an apple breeding program, we have examined the pollen effect on the fruit appearance and inner quality of different apple cultivars in the Corvinus University of Budapest Department of Fruit Science. Five apple cultivars ('Golden Reinders', 'Regal Prince', 'Rewena', 'Renora', 'Idared') have been crossed by the pollen of some new and some traditional cultivars in our experiment. The measurements were carried out in the analytic and fruit examining laboratory of the Department of Fruit Science. The diameter, height and stem length were measured by digital caliper. We have also examined the squash ratio, soluble solid- and acidic content. Sugar content was calculated by a schedule released by the International Sugar Committee (ISC). From the sugar- and acidic content, we could also count the Pomona-value. We have observed interesting effects according to some attributes in some crossing combinations with the help of statistical analysis. Crossing 'Golden Delicious' with 'Freedom', 'Prima', and 'Baujade' have resulted in smaller fruit size than other combinations. No significant differences could be observed on `Golden Reinders' fruits according to metaxenic coloration in the year of the examination. On the other hand the color modifying effect of pollen donating cultivars have manifested on the red fruits of 'Regal Prince' (Gala Must). `Freedom' as a pollen donating cultivar has resulted outstanding value in our consistency measurements. Squash ratio was the highest in combinations pollinated by 'Prima' and `Reglindis'. We have noticed balanced values when measuring inner qualities, only `Reka' has caused lower acidic content. Significant differences have been found in combinations according to the number of frivolous seeds. No frivolous seeds were found in the combinations 'Golden Reinders' x 'Freedom' and 'Idared' x 'Prima'. Almost two frivolous seeds were found in the fruits of the combination 'Renora' x 'Sóvári' in average.

Cryogenic Storage of Tomato Pollen: Effect on Fecundity

The influence of cryogenic pollen storage on fruit set and seed production in tomato (Lycopersicon esculentum Mill.) was investigated. Flowers pollinated with pollen samples stored for 5 weeks at –80C, with or without 20 h precooling at 4C, had similar fruit set and number of viable seed per fruit as those pollinated with fresh pollen. Pollen samples, which were repeatedly cooled (–80C) and warmed (to 22 to 24C) for up to six cycles, continuously maintained the same viability as the fresh pollen. When cryogenically stored pollen of L. esculentum 2-837, LA359, LA3198, and LA3199 were used to pollinate LA359, the number of viable seed formed per fruit differed significantly. Results of this study suggest that pollen cryopreservation can be used successfully for tomato breeding and germplasm storage.