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Roses are one of the most highly produced and purchased ornamental plants worldwide. Procurement and preservation of pollen is essential for the production of diverse rose varieties. In this study, we analyzed pollen management conditions, such as the pollen collection stage, drying time, and storage temperature, to determine optimal conditions for rose pollen management. Pollens were stored under different conditions and the pollen vitality and germination rate were investigated through an optical microscope. The vitality of pollen was an essential factor for rose breeding and depended on the storage conditions. Collecting pollen in the seventh flowering stage resulted in a relatively higher pollen yield. Drying the flower for 5 h after the anther opened improved pollen germination. The germination rate of freshly collected pollen was similar to that of pollen stored at temperatures between −20 °C and −72 °C for up to 30 days, indicating the efficacy of pollen storage at sub-zero temperatures. Since the rate of fruiting increases when pollination is performed three times, considering the time and cost of breeding, it is appropriate to pollinate three times to increase the number of seeds. This study provides an efficient pollen management method to collect and store pollen for breeding. [ABSTRACT FROM AUTHOR]

Among many challenges in chrysanthemum cross-breeding, the access to viable pollen for hybridization of cultivars distant in location and different in flowering time is required. Low pollen viability along with incompatibility are mainly responsible for low seed set in modern chrysanthemum cultivars. The aim of the study was to test various temperatures and periods of pollen storage of Chrysanthemum × morifolium in order to elaborate the method of chrysanthemum pollen preservation for cross-breeding purposes. In the first experiment, in vitro pollen germination of four cultivars was investigated following storage at 20 °C, 4 °C, −20 °C, and −80 °C, for one, four, and eight weeks. The second experiment focused on in vivo seed set after one week pollen treatment with 20 °C, 4 °C, −20 °C, and −80 °C (three pollen donor cultivars tested). Pollen in vitro germinability, as well as seed set efficiency, was generally low and cultivar dependent. Independent of the period of storage, stored pollen germinability was lower (5.30–6.63%) than fresh pollen (8.15%). Incubation of pollen in −80 °C significantly increased pollen germinability (9.80%), as well as seed set efficiency in comparison to control (19.28% and 10.21%, respectively) provided the cultivars are compatible. Among cultivars, the highest germinability of pollen was found in 'Brda' and 'Donna' (8.2% and 8.23%, respectively), while 'Bydgoszczanka' showed the lowest germinability (2.97%). There were also pollen genotype dependent effects in in vivo seed set efficiency, which was highest in 'Brda' (17.57%) and much lower in 'Jutrzenka' and 'Polka' (1.34% and 0.39%, respectively), which contributed to the incompatibility of crossed cultivars rather than pollen viability. [ABSTRACT FROM AUTHOR]

Heat tolerance is important for the sustainable production of many crops, including chile pepper. Tolerance to high temperature is complex and involves various component traits, with pollen viability being among the most important. in vitro pollen assays for heat tolerance have been widely used in chile pepper; however, associations between the pollen treatment and pollination have not been widely explored. The objectives of this study were to validate the utility of in vitro heat stress pollen characterization through in vivo pollination during summer and winter seasons and to evaluate the cross-compatibility among wild and domesticated species to initiate introgression population development. Seven entries of wild and domestic Capsicum species grown during the summer and winter seasons were used to evaluate pollination success rate. Pollen was either used directly or treated at 38 °C for four hours before making reciprocal self- and cross-pollination among all the entries. Significant associations between in vitro pollen treatment and pollination success rate during summer and winter seasons were identified. Heat treatment was a greater contributor to variability than the growing environment, which validates previous reports on the usefulness of studying pollen in vitro in selection for heat tolerance. Accessions of the wild progenitor C. annuum var glabriusculum, PBC 1969 and PBC 1970, were identified as a potential heat-tolerant source for use in breeding and future research. This work provides a basis for future research in exploring additional heat tolerance components as well as for the development of phenotyping assays for pollen or other floral traits. [ABSTRACT FROM AUTHOR]

Our study attempted to elucidate the significance of floral and pollen traits of the highly nutritious tropical trees Moringa oleifera and Moringa peregrina for their reproductive success under arid conditions. We found that the pollen grains of both species were immersed in a pollenkitt that constituted ~60% of the pollen. Successful pollination was achieved by large bees inserting the pollen into a narrow stylar tube. We found that, upon removal of the pollenkitt, approximately 65% fewer pollen grains penetrated the stylar tube for both species. The pollenkitt protected against heat and desiccation, while removing the pollenkitt resulted in significantly reduced levels of the viability of pollen grains, especially in M. oleifera, and significantly reduced levels of germinability in both species. The stylar tube provided high protection for pollen grains against heat and desiccation even when the pollenkitt was removed. Chemical analysis of pollenkitts of the two species revealed a waxy blend of 21 hydrocarbon compounds, in which n-alkanes constituted >90% of the compounds and their identity corresponded to known plant and animal hydrocarbons, associated with protection against heat and water stress. We concluded that, under arid conditions, the reproductive success of both Moringa species is potentially enhanced by their unique floral and pollen traits. This supports the prospect of cultivating M. oleifera and Moringa peregrina as food crops in arid regions across the globe. [ABSTRACT FROM AUTHOR]