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A study was conducted in a yard long bean (Vigna unguiculata sup/ssp. sesquipedalis) hybrid VS 50 (Kakkamoola Local) x VS 26 (Vellayani Jyothika) to assess the percentage fruit set at two time intervals and to identify the best time interval for pollination in yard long bean hybrids. Hand pollination was done using VS 50 as female parent and VS 26 as male parent for seven consecutive days at two time intervals, 6.30 – 7.30 am and 7.30 – 8.30 am. Higher percentage of fruit set (36.8 %) was observed between 6:30 – 7:30 a.m. as compared to the time interval 7:30 – 8:30 am. (23.8%). Pollen viability was determined for the parents VS 50 (Kakkamoola Local) and VS 26 (Vellayani Jyothika) at 6.30, 7.30 and 8.30 am. Highest pollen viability for both the parents VS 50 and VS 26 was observed during 7.30 am. The present study shows that the best time interval for crossing in yard long bean is 6.30- 7.30 a.m.

Success artificial pollination with viable pollen is crucial process in the production chain of date palms. This study evaluated the impact of pollen storage temperature and duration, pollination time following spathe cracking, and the hour of daytime on pollen viability, germinability, fruit set and yield of 'Deglet Nour' date palm cultivar. In in vitro tests, fresh pollen showed the maximum viability (96.3%) and germination (85%) but it decreased thereafter upon the storage temperature (28, 4 and −30 °C) and duration (3, 6, 9 and 12 months). In this respect, pollen stored at −30 °C retained highest viability and germinability followed by those stored at 4 and then at 28 °C. In filed experiments, fruit set was 85, 75, 65, and 45% with pollination using fresh pollen, or pollen stored at −30, 4 and 28 °C, respectively. Fruit set was 95%, 75%, and less than 50%, for pollination performed on the same day of spathe cracking, 6 and 12 days later, respectively. The highest fruit set percentage and yield/bunch were obtained with pollination performed between 12.0 pm and 15.0 pm in contrast to 8.0–11.0 am or 16.0–17.0.

The planting of monsoon rice (locally known as aman rice) may be delayed due to late heavy rainfall in many regions of South and Southeast Asia resulting in high spikelet sterility with substantial yield loss due to low temperatures during the reproductive stage. Therefore, the study evaluated the performance of foliar-applied boron in mitigating that problem towards sustainable aman rice production. A field experiment was laid out in a randomized complete block design where different levels of boron viz. 0, 50, 100, 150, 200, and 250 ppm were foliar-sprayed at 33 and 47 days after transplanting (DAT) to a popular aromatic rice cultivar Kataribhog grown in late monsoon. Data were collected on phenology, SPAD value at variable dates, pollen viability, boron concentration in leaves and grains, and yield traits and yield. The pollen viability increased by 81.6% for 200 ppm boron. Boron decreased flag leaf weight but increased panicle weight. Simultaneously, it decreased flag leaf SPAD value and subsequent increase in grain yield, which indicates profound flag leaf reserves translocation into the grain. Foliar-applied B at 200 ppm showed a 32.4 and 40.9% increase of B in leaf and grain, respectively, and improved yield attributes resulting in grain yield by 47.0%. The grain yield had strong positive relations with the B content in leaf and grain, and yield contributing characters. The results conclude that foliar-applied appropriate dose of B can reduce spikelet sterility, individual grain weight and eventually enhance grain formation towards increasing yield in late sown aromatic monsoon rice. [Fundam Appl Agric 2021; 6(3.000): 232-244]

A quick and trusted method for evaluating pollen quality and viability is essential in a conventional breeding program. Techniques used in evaluating pollen viability can be classified into in vivo and in vitro tests. Harrison, Heslop, Harrison and Shivanna (2004) categorize the in vitro test into (a) test of germinability, (b) test of stainability, (c) test for enzyme activity and (d) fluorochromatic procedure (FCR). Using pollen of different age crossability can be suitable in testing pollen viability in the field. This research work was conducted in 2007 and 2008 at the screen house of the Institute for Agricultural Research (IAR) of Ahmadu Bello University Samaru Zaria to study pollen viability and its implication for outcrossing in cowpea. Four genotypes, IT86D1010, IT93K452-1, B301 and kanannado were used in the study. Completely Randomized Design (CRD) was used where each cultivar was sown in four labeled pots containing topsoil mixed with manure and sand. This set of planting was repeated three times but staggered to synchronize the flowering of the genotypes. Pollen grains were collected early in the morning (6:00- 6:30 am) from a matured pollen and kept in a well-labeled Petri dish in a filter paper. The crossing was done immediately after pollen collection at 0 hours, then after 3 hours of collection and 6 hours. The crossing was done in all forms, including reciprocals. Record of successful and failed crosses was taken when pods started to form. A regression analysis of pollen age on percent successful cross was carried out to determine the crossability, pollen viability, and relationships. The study shows that the three varieties, IT86D1010, IT93K452-1 and B301 were readily crossable both as paternal and maternal parents. Kanannado was crossable as a paternal parent only, but no seed was recorded when used as a maternal parent. Regression analysis shows a significant effect of pollen age on pollen viability and crossability. The experiment suggests that pollen from neighboring plants can threaten breeding materials if transferred by an efficient vector since pollen can be viable under ambient temperature for up to three hours. Keywords: In-Vivo, pollen, longevity, cowpea, viability

Turkey is the leading country in the production of world apricots (Prunus armeniaca). In the country, apricots are usually grown for drying and fresh consumption, and apricots are also used for different purposes. This study was carried out to determine pollen viability and germination status in some foreign apricot varieties grown in Mut district of Mersin province, which has an important place in early ripening apricot production in Turkey. Pollen viability and germination ratios were determined by TTC and 1% agar 10% method in Mogador, Mikado, Pricia, Flopria apricot varieties. In terms of pollen values, the best result in terms of viable pollen is from the Mikado with 77.02% and Mogador varieties with 78.61%, while the Pricia variety with 44.09% in semi-viable pollen provides the most result, while Flopria and Pricia varieties produce the highest values in dead pollen results. In the germination tests, pollen germination rates were medium level in Flopria, Mogador and Mikado varieties the pollen germination rate of the Pricia variety is only 8.96%. The results obtained will be a guide in new orchard establishment and breeding studies.

Pollen viability and germinability are indispensable criteria in plant breeding programmes. This research evaluated eleven M4 mutant lines of gamma irradiated sesame (Sesamum indicum) for some pollen parameters. Seeds were obtained from the Department of Plant Biology, Federal University of Technology, Minna and were raised to maturity alongside their respective checks in a randomized complete block design (RCBD). The field experiment was conducted at the experimental field of the Upper Niger River Basin Development Authority, Minna. Pollen viability and diameter were determined using standard procedure. The germinability test was done using three different sucrose concentrations (10 %, 20 % and 30 %) with 1 % nutrient agar solution. The results revealed that all the M4 mutant lines had adequate pollen viabilities (over 80%) with ML-10 having the highest (97.56 %) viability followed by ML-7 (95.61 %), ML-8 (95.01 %) and Check-2 (95.60 %). The highest pollen germinability was recorded at 20 % sucrose concentration for all the mutant lines with line ML-7 (39.70 %) having the highest percentage. Check-1 at 10 % sucrose concentration recorded the least percentage (11.46 %) across the concentration and treatments. Highest pollen diameter (169.52μm) was recorded in Check-1. Suboblate shapes with 10-13 colpi was observed in all the mutant lines and the checks. Pollens from all the lines comprised of circular and elliptic pollens except in ML-7 and the checks where the pollens were solely circular in polar view. The study revealed that gamma-irradiation could be a reasonable tool for inducing variability in sesame and advantageous in increasing the pollen viability.

The objective of this study was to evaluate genetic stability by determining the meiotic index (MI) and pollen viability in F1RC2 segregating populations, obtained by the crosses between wheat commercial cultivars and synthetic wheat, aimed at introgression/genetic resistance. For MI, three ears were collected per genotype, before anthesis, and they were fixed in Carnoy’s solution. The cytological slides were prepared by crushing the anthers and staining with 1% acetocarmine, and the normal tetrads and the ones with micronuclei were observed under a light microscope. For pollen viability, the ears were collected at the stage of mature pollen grain. The methodological procedure was similar to that of the tetrads, evaluating the pollen grains as viable, with little starch, with two pores, different sizes and non-viable. The pollen grain size was measured by the Axion Vision software. All the segregating populations with MI above 90% and high pollen viability (above 85%) reflected a stable meiotic behavior. About the variation in size, the CIGM90.909/BRS 179 cross showed pollen grains with 58.43 μm and CIGM93.298/BRS Guamirim, 47.15 μm. According to the results, wheat segregating populations were considered meiotically stable and suitable for use in wheat breeding programs and for incorporation of new important genes. O objetivo do estudo foi verificar a estabilidade genética, determinando-se o Índice Meiótico (IM) e a viabilidade polínica em populações segregantes F1RC2, oriundas do cruzamento entre trigos sintéticos e cultivares comerciais de trigo, que visam introgressão/resistência genética. Para o IM, três espigas foram coletadas por genótipo, antes da antese, e fixadas em Carnoy. As lâminas citológicas foram preparadas pelo método de maceração com corante carmim acético 1%, observadas em microscópio ótico e analisadas tétrades normais e com micronúcleos. Para a viabilidade polínica, as espigas foram coletadas no estágio de grãos de pólen maduro. O procedimento metodológico foi semelhante ao das tétrades, avaliando-se: grãos de pólen viáveis, com pouco amido, com presença de dois poros, tamanhos diferentes e inviáveis. O tamanho dos grãos de pólen foi medido pelo programa Axion Vision. Todas as populações segregantes apresentaram IM acima de 90% e viabilidade polínica elevada (acima de 85%), refletindo comportamento meiótico estável. Quanto à variação no tamanho, o cruzamento CIGM90.909/BRS 179 apresentou grãos de pólen com 58,43 µm e CIGM93.298/BRS Guamirim, 47,15 µm. Com base nos resultados, as populações segregantes de trigo apresentam-se meioticamente estáveis e adequadas para seguirem em programas de melhoramento de trigo e incorporação de novos genes importantes.

Plants adapt to heatviathermotolerance pathways in which the activation of protein folding chaperones is essential. In eukaryotes, protein disulfide isomerases (PDIs) facilitate the folding of nascent and misfolded proteins in the secretory pathway by catalyzing the formation and isomerization of disulfide bonds and serving as molecular chaperones. In Arabidopsis, several members of the PDI family are upregulated in response to chemical inducers of the unfolded protein response (UPR), including both members of the non-classical PDI-M subfamily, PDI9 and PDI10. Unlike classical PDIs, which have two catalytic thioredoxin (TRX) domains separated by two non-catalytic TRX-fold domains, PDI-M isoforms are orthologs of mammalian P5/PDIA6 and possess two tandem catalytic domains. Here, PDI9 accumulation was found to be upregulated in pollen in response to heat stress. Histochemical staining of plants harboring thePDI9andPDI10promoters fused to thegusAgene indicated they were actively expressed in the anthers of flowers, specifically in the pollen and tapetum. Immunoelectron microscopy revealed that PDI9 localized to the endoplasmic reticulum in root and pollen cells. transfer DNA (T-DNA) insertional mutations in thePDI9gene disrupted pollen viability and development in plants exposed to heat stress. In particular, the pollen grains ofpdi9mutants exhibited disruptions in the reticulated pattern of the exine and an increased adhesion of pollen grains. Pollen in thepdi10single mutant did not display similar heat-associated defects, butpdi9 pdi10double mutants (DMs) completely lost exine reticulation. Interestingly, overexpression ofPDI9partially led to heat-associated defects in the exine. We conclude that PDI9 plays an important role in pollen thermotolerance and exine biogenesis. Its role fits the mechanistic theory of proteostasis in which an ideal balance of PDI isoforms is required in the endoplasmic reticulum (ER) for normal exine formation in plants subjected to heat stress.

Existence of cytomixis and associated meiotic anomalies, their effect on pollen viability/size and factors influencing cytomixis have been described in many species but not in Mentha longifolia. Presently, meiotic analysis of four M. longifolia populations from varying altitudes of Jammu Province (Jammu and Kashmir, India) revealed cytomixis between 16.67 and 19.31% pollen mother cells (PMCs) in three populations (considered cytomictic) and in 3.43% cells in the fourth one (named control). For each population, the frequency of cytomictic cells valued nearly same irrespective of the type of anthers (fresh/fixed) used and season (peak blooming/offseason) of their collection indicating that cytomixis is not influenced by seasonal variations/fixative treatment. To determine whether/not cytomixis in present populations is associated with numerical or structural chromosomal variations, meiocytes were scrutinized for chromosome count and behaviour. While PMCs of control population contained diploid chromosomes (2n = 24) exhibiting regular behaviour, 4.73 to 11.27% cells of cytomictic populations were aneuploid (2n = 22, 25 and 26)/nearly haploid (2n = 14)/polyploid (2n = 42/44) or had multivalents. In later populations, the presence of 17–19% cytomictic and 7.52–11.27% cytologically deviant cells accounted for low pollen viability (33.19–37.27%), with some of viable pollens (16.92 to 20%) being larger/smaller than normal one. However, control population containing few (3.43%) cytomictic cells exhibited high pollen viability (61.78%). In M. longifolia, finding of connected cells in all the four populations for two consecutive years points towards natural occurrence of cytomixis and is not a fortuitous event. Nevertheless, variation in the frequency of cytomictic cells in different populations seems to have some connection with environmental conditions where they were growing.

Knowledge gap on the reproductive biology of orphan crops is a major challenge to their cultivar development and genetic improvement. This study described the reproductive organs and phenology, assessed receptivity of stigma versus anther dehiscence, and examined pollen viability and germination in Kersting's groundnut. Experiments were conducted on nine morphotypes in a randomized complete block design with three replications in a screenhouse. Phenological observations were made on 1026 flower buds. Anther dehiscence was determined through microscopic observations while receptivity of the stigma was assessed using the hydrogen peroxide test. Pollen viability was assayed using histochemical staining. In vitro germination and pollen tube growth were assessed for up to 72h. Flowers were bisexual and incompletely protogynous, and spontaneous self-pollination was favoured by style bending. Flowering and fruiting were classified into six developmental stages each. Timing of all stages differed significantly (P

Pollen viability and in vitro pollen germination was examined in single and double types of Nerium cultivars. Maximum pollen viability per cent was recorded in the cultivar UHSBN-6 (97.90%) followed by the cultivar UHSBN-14 (95.68%) and least per cent was recorded in the cultivar UHSBN-24 (89.58) when methyl blue was used as a dying agent. Potassium iodide showed the maximum per cent pollen viability in the cultivar UHSBN-12 (95.66%). Further, maximum in vitro pollen germination was recorded in the cultivar UHSBN-19 (68.69%) in 15% sucrose with 100 ppm boric acid which was on par with the cultivar UHSBN-17 and UHSBN-29 (67.18 and 66.90% respectively). The cultivar UHSBN-12 recorded maximum in vitro pollen germination (77.12%) under Brew baker and Kwack medium which was on par with cultivars UHSBN-19 and UHSBN-30 (74.80 and 74.72% respectively). The results obtained from the present investigation can aid in planning crosses and establishment of Nerium hybridization programs using compatible cultivars.

The present study describes the floral morphology and evaluates pollen viability for the bromeliad Nidularium minutum Mez. during the flowering period 2018‒2019 through histochemistry and pollen ge...

Background In a breeding program, usually only superior parents are chosen for cross hybridization. Pollens of elite cultivars may not be available at hand. Properly stored pollens provide an opportunity for cross hybridization at unavailable time. Results Pollen of a Phalaenopsis hybrid was evaluated for the storage ability at different temperatures, including room temperature, 4, − 20, and − 80 °C for up to 96 weeks. The viability of pollen was assessed by TTC staining, in vitro germination and hand pollination during and after storage. Pollen stored at all temperatures for 4 weeks remained viable and capable of successful pollination. Pollen lost its viability after 4 weeks at room temperature. Pollen remains viable after 40 weeks at 4 °C, and after 96 weeks at both − 20 and − 80 °C of storage. Viable pollen could be successfully pollinated to the female parent at all effective storage conditions and produced seeds. Conclusions Our results indicate that Phalaenopsis pollen can be stored at 4 °C up to 40 weeks for short-term purpose. For long-term storage, pollen can be kept at both − 20 and −80 °C.

High-quality pollen is a prerequisite for plant reproductive success. Pollen viability and sterility can be routinely assessed using common stains and manual microscope examination, but with low overall statistical power. Current automated methods are primarily directed towards the analysis of pollen sterility, and high throughput solutions for both pollen viability and sterility evaluation are needed that will be consistent with emerging biotechnological strategies for crop improvement. Our goal is to refine established labelling procedures for pollen, based on the combination of fluorescein (FDA) and propidium iodide (PI), and to develop automated solutions for accurately assessing pollen grain images and classifying them for quality. We used open-source software programs (CellProfiler, CellProfiler Analyst, Fiji and R) for analysis of images collected from 10 pollen taxa labelled using FDA/PI. After correcting for image background noise, pollen grain images were examined for quality employing thresholding and segmentation. Supervised and unsupervised classification of per-object features was employed for the identification of viable, dead and sterile pollen. The combination of FDA and PI dyes was able to differentiate between viable, dead and sterile pollen in all the analysed taxa. Automated image analysis and classification significantly increased the statistical power of the pollen viability assay, identifying more than 75,000 pollen grains with high accuracy (R2 = 0.99) when compared to classical manual counting. Overall, we provide a comprehensive set of methodologies as baseline for the automated assessment of pollen viability using fluorescence microscopy, which can be combined with manual and mechanized imaging systems in fundamental and applied research on plant biology. We also supply the complete set of pollen images (the FDA/PI pollen dataset) to the scientific community for future research. Electronic supplementary material The online version of this article (10.1007/s00497-020-00398-6) contains supplementary material, which is available to authorized users.

Study was conducted to investigate pollen viability of four mango varieties, viz. Kesar, Alphonso, Mallika and Dudhpendo up to 56 days. Pollen grains were suspended in three different media (n-hexane, paraffin oil and without media) under four different storage temperature (-20 ⁰C, -4 ⁰C, 4 ⁰C and room temperature). Aceto-carmine test was used to determine pollen viability. Variation due to different varieties, media, temperature and their interactions was found significant. Among four varieties, maximum viability was recorded in Kesar during 7, 14, 21, 49 and 56 days of storage, whereas, in Mallika, at 28, 35 and 42 days. In storage media, n-hexane was found best in terms of retaining viability. The storage at -20 ⁰C gave better results in terms of viability in all four varieties. On the basis of results, it could be concluded that pollen grains of Kesar and Mallika could be stored successfully up to 56 days in n-hexane at -20 ⁰C.

Ultra-morphology and pollen viability assessment are essential to understand evolutionary ecology and sterility problem, and to design hybridization program in cross-breeding. The pollen ultra-morphology of two Lilium Oriental hybrid cultivars, „Sorbonne‟ and „Siberia‟ were observed using scanning electron microscope. And the pollen germination condition in vitro and four dye tests methods for pollen viability were determined. The results showed that pollens of two Lilium Oriental hybrid cultivars were much alike in ultra-morphology with ellipsoidal shape, reticulate surface decoration and single germination ditch, indicating a close genetic relationship between two cultivars. The suitable medium for pollen germination of two cultivars composed of 10% sucrose, 0.1% boric acid and 0.5% agar. The pollen germination percent reached the highest at 25oC. Although I2-KI stain, TTC stain and peroxidase precipitation methods were not suitable for lily pollen viability test, the pollen viability tested by acetocarmine method were close to that by in vitro pollen germination at suitable condition, which suggested acetocarmine stain can be as a quick test method for pollen viability of Lilium Oriental hybrids. © 2018 Friends Science Publishers

Field pea (Pisum sativum L.), a major pulse crop in western Canada, is sensitive to elevated temperature and possibly to high night temperature. Our objective was to examine if increasing night temperature while maintaining a constant daytime temperature affected pollen viability and seed set in two pea cultivars (CDC Golden and CDC Sage). Cultivars were exposed to 27/18, 27/22, 27/26 °C (day/night temperatures) for 7 d during flowering stage. Results indicated that increased night temperatures had no significant effect on pollen viability, the number of reproductive nodes and flowers, percentage of flower abortion, seed number per pod, and seed yield per plant.

Cistus species are widespread in the Mediterranean basin, even in places characterized by high temperatures and arid soils. Despite a rich literature concerning the biological and pharmacological properties of Cistus genus, to our knowledge, there are only a few reports on pollen viability and little is known about microbial endophytes within pollen grains. Pollen viability and germination of Cistus creticus L. and Cistus monspeliensis L., from two sites of Sicily (Italy) over two years (2016-2017), were determined by 2,3,5 tryphenil-tetrazolium chloride (TTC) staining and an in vitro germination test. Dominant microorganisms, flowing from pollen openings (colpora), were identified by molecular methods. Furthermore, for comparison, in 2017 microbial endophytes of C. eriocephalus Viv. from Serra S. Bruno (Calabria, Italy) were studied. The optimal medium composition for rapid in vitro germination was determined. Pollen viability was in the range 79.8-90.0% for C. monspeliensis and 86.6-91.6% for C. creticus, while germination was in the range 56.5-62.4% for C. monspeliensis and 50.1-58.8 for C. creticus. Statistical analysis by correlation coefficient showed a significant relationship between viability and germination, whereas significant differences (P

A present study was carried on floral biology of rice that cover anther dehiscence, pollen viability and stigma receptivity was carried out with the aim to improve the efficiency of hybridisation in rice breeding work at the Experimental farm of Regional Agriculture Research Station, Karjat (Raigad) during kharif 2016. In this study, three CMS lines viz., IR58025A, RTN 12A and RTN17A and four testers i.e., Chedo Local, CR-2829-PLN-36, NPQ-49 and RP-5898-19-8-6-1-1-1 of rice were used. The results reported that the time required for dehiscence of anther ranged from 8 - 20 minutes in testers of rice. The results showed that time of anthesis in both the CMS lines and testers of rice since 08.00 AM. In the pollen viability study, results suggested that pollens are more viable from single minute to 11 minutes after anther dehisced at fully blooming stage. The range of pollen viability percentage was observed from 90.79% to 94.92%. However, there are variations among the genotypes for the optimum viability of pollen at maximum blooming stage. In both CMS lines and testers of rice, maximum blooming stage of panicles was recorded 9.00 am to 1.00 pm while 8.00-11.00 days took for fully completion of anthesis. In CMS lines of rice, receptivity of stigma ranged from 36 to 42 hrs (two to three days). There was no difference in stigma receptivity stages among the three CMS lines of rice. Thus, the precise knowledge of floral biology, which includes structural and functional aspects of rice inflorescence, is essential for breeders to plan and execute breeding strategies.

After cryopreservation, the occurrence of apoptosis-like programmed cell death events induced by the accumulation of ROS reduces pollen viability. Cryopreservation, as a biotechnological means for long-term preservation of pollen, has been applied to many species. However, after cryopreservation, the viability of pollen significantly decreases via a mechanism that is not completely clear. In this study, the pollen of Paeonia lactiflora ‘Zi Feng Chao Yang’, which exhibits significantly reduced viability after liquid nitrogen (LN2) storage, was used to study the relationship among pollen viability, programmed cell death (PCD) and reactive oxygen species (ROS). The apoptosis rate was increased significantly in pollen with decreased viability after cryopreservation, and the changes in ROS generation and hydrogen peroxide (H2O2) were consistent with the apoptosis rate. Correlation analysis results showed that the apoptosis rate is positively correlated with ROS generation and H2O2 content. In addition, ascorbic acid (AsA), glutathione (GSH) and ascorbic acid reductase (APX) levels were significantly correlated with ROS and H2O2. After LN2 preservation for 8 months, the exogenous antioxidants AsA and GSH at appropriate concentrations significantly decreased H2O2 content, inhibited PCD indicator levels, and increased cryopreserved pollen viability. These observations suggest that PCD occurred in pollen during LN2 preservation for 1–8 months and was induced by the accumulation of ROS in pollen after cryopreservation, thus explaining the main reasons for the reduction in pollen viability after cryopreservation in LN2.

This studys important for determining the different temperatures’ effect (4, 18 and 24 ° C) on pollen germination and its viability for some strawberry (‘Premial’, ‘Clery’, ‘Real’, ‘Mira’, ‘Alba’, ‘Idea’, ‘Elsanta’, ‘Onebor’, ‘Benton’) and blackberry (‘Lock Tay’, ‘Williams’, ‘Arapaho’, ‘Black Satin’, ‘Navaho’, ‘Hull’) cultivars. The pollen viability was determined through the acetic carmine staining method. The fertile pollen was colored in red, and the sterile one in pink or it remained colorless (1.5 g agar + 15 g sucrose + 0.01 g boric acid in 100 ml distilled water), incubated 6-8 hours at all three temperatures and relative humidity 70-90%. The temperature affected the pollen germination and the cultivars germination capacity. The lowest pollen germination rate was obtained at 4 °C (between 19.4 1% and 54.72% for strawberry and 9.10% and 24.35% for blackberry). The best strawberry results were observed at 18 °C (57.97% in the Mira cultivar), respectively 24 °C (56.77% in the Elsanta cultivar) and at 18 °C (50.13% Williams variety), respectively 24 °C (55.55% Arapaho variety).

The environments have a direct impact on formation and functioning of the generative organs in plants. Parameters characterizing viability of pollen grains are closely linked with weather conditions, especially temperature and air moisture. Very often a phase of a beginning of flowering of winter rapeseed (end of March – beginning of April) lasts in unfavourable conditions. In April 2020, we studied influence of the main weather factors (frosts, low moisture) on germination of pollen grains of the varieties Loris, Sarmat and hybrids 40059 × Jesper 16– 132 and 40008 × INRA of winter rapeseed bred in VNIIMK. Pollen viability was determined by B.A. Trankovsky’s method, accounting amount of germinating pollen grains on the artificial nutrient medium, calculating a percentage of germinating pollen grains to their total quantity. We determined optimal concentration of sucrose solution (20%) in a nutrient medium for germination of pollen of winter rapeseed varieties and hybrids. Due to our results, lowered air temperatures (from -0.5 to -1.9 оС) combined with air moisture from 39 to 86% in a period of beginning of crop flowering negatively influenced on germination of pollen grains. Viability of pollen of the varieties Loris and Sarmat was in average 47 and 37%, respectively. Pollen grains of the hybrids (F1 40059 × 52 Jesper 16-132 and F1 40008 × INRA) had less viability – 38 and 21%, respectively, this certifies higher susceptibility of tissues of the reproductive organs to low temperature and moisture.

Research Highlights: Cyclocarya paliurus, native to the subtropical region of China, is a monoecious species with a heterodichogamous mating system. Its flowering phenology and low seed success characteristics differ from other typical heterodichogamous Juglandaceae species. This could be caused by the existence of polyploidy in the population. Background and Objectives: C. paliurus has been attracting more attention as a result of its medicinal value. To meet the needs for leaf harvest, cultivation expansion is required, but this is limited by a shortage of seeds. This study aims to profile the flowering phenology and the efficacy of pollen dispersal as well as elucidate on the mechanism of low seed success in the population. Materials and Methods: The flowering phenology pattern of C. paliurus was observed in a juvenile plantation containing 835 individuals of 53 families from 8 provenances at the individual (protandry, PA and protogyny, PG) and population levels for 5 consecutive years (2014&ndash, 2018). Slides with a culture medium of 10% sucrose and 0.01% boric acid were used to estimate pollen density and viability in the population, and seeds were collected from 20 randomly selected PA and PG individuals to assess seed success during 2017&ndash, 2018. Results: Four flowering phenotypes and strongly skewed ratios of PA/PG and male/female occurred in the juvenile population. Sexual type and ratio changed significantly with the growth of the population over the years, showing an increasing monoecious group (11.1% to 57.2%) and a decreasing unisexual group (33.6% to 16.3%), as well as a tendency for the sexual ratio to move towards equilibrium (5.42:1 to 1.39:1 for PG:PA). Two flowering phases and bimodality in gender were displayed, as in other heterodichogamous species. However, the high overlap of inter-phases and within individuals was quite different from many previous reports. Owing to the low pollen viability of C. paliurus (~30%), low seed success was monitored in the plantation, as well as in the investigated natural populations. Conclusions: Female-bias (PG and F) and a skewed ratio of mating types corresponded to nutrient accumulation in the juvenile population. Heterodichogamy in C. paliurus was verified, but was shown to be different from other documented species in Juglandaceae. The latest finding of major tetraploidy in a natural population could explain the characteristics of the flowering phenology and seed set of C. paliurus and also give rise to more questions to be answered.

Genotypes of Cyclopia, used to produce honeybush tea, are being improved through selective breeding for suitability in large-scale cultivation and consistent flavour/aroma qualities. Though high levels of natural fecundity have been reported in honeybush species, attempts at controlled crosses have hitherto resulted in virtually no seed set. While investigating this problem, it was found that many basic questions regarding the specific reproductive physiology of the genus have not been answered. Studies were undertaken to provide the necessary data about sexual reproduction in honeybush species, in support of existing breeding programmes. This paper presents data concerning pollen viability in relation to flower bud stage, storage and pollen surface morphology of C. longifolia, C. maculata and C. subternata. Pollen anthesis and viability (measured as in vitro pollen germination percentage - PGP 1 ) were linked to visual stages of flower bud development. Pollen samples, dried and stored for 540 days at -18 °C, were tested for PGP at intervals (7, 30, 90, 180, 365, 540 days) during the storage period. While there was an overall decrease in PGP over storage time, four genotypes did not have any significant decrease in PGP over time. The effect of media sucrose content (MSC 2 ) (0–25%) on in vitro PGP of honeybush pollen was tested and differences in response were observed between species. Pollen surface morphology was investigated using FE-SEM microscopy and no consistent differences in shape or surface ornamentation were observed between the species, though differences in grain size were observed.

The present study envisaged the effects of two mutagens, gamma rays and EMS on the phenotypes of two sesame varieties viz., TMV7 and SVPR1. A known quantity of dry, uniform, and healthy seeds of TMV7 and SVPR 1 were irradiated using Co60 (Cobalt 60) with different doses (250, 300, 350, 400, 450 Gy) of gamma rays. For chemical mutagenesis, different concentrations of EMS @ 0.20%, 0.40% and 0.60% was used and treated for 8 h. The dose-response curve of the probit analysis showed that the optimal lethal dose for SVPR1was lower than TMV7. The expected LD50 values of gamma radiation for TMV 7 and SVPR1 were 403.91Gy and 343.84Gy, respectively. For EMS, the expected LD50 values are 0.525 % and 0.276% for TMV7 and SVPR1 respectively. Germination and pollen fertility declined linearly with an increase in dose or concentration of the mutagens. Three classes of chlorophyll mutants viz., xantha, chlorine, and viridis in M2 generation reveals a dose dependent relationship between mutagens and frequency of chlorophyll mutants. Mutagenic effectiveness was higher at lower doses whereas mutagenic efficiency was observed higher at extremity doses in both the varieties. The overall considerations on M1 generation effects showed that SVPR1was highly sensitive to gamma rays and TMV7 produced more viable mutationsthan SVPR1. The current studies suggest gamma rays as an efficient mutagen to induce essential mutations in TMV7 for the further crop improvement program.

Early water deficit at bloom results in poor berry set and/or a grape yield reduction. The purpose of this work was to determine the effects of early water stress in a berry's development. The experiment was carried out in a SupAgro ECOTRON System in Montpellier, France. Seven year- old 'Syrah' vines were used. The pot's surface was protected from rainfall, and the growing medium was perlite+coarse sand with controlled drainage. The treatments were WS0 (control): 41/day, WS1.: 3 l/day, WS2 : 2 l/day, and WS3 : 1 l/day. 'Ihe water deficit was carried out from the 17th to the 27th Eichhorn-Lorenz (E-L) stages. In order to emphasise details of the embryo development, a paraffin section method and technique was used. With the early water stress, there was no effect on the pollen viability and pollen germination ratios. The berry set ratio was reduced and the berry development were affected negatively by the early water stress. Between the 19th and the 27th E-L stages, an early water stress in 'Syrah' was noted, with decreases in the pre-dawn leaf water potential values below -0.8 MPa. The water deficit affected the berry growth and the development negatively.

After cryopreservation, the NO content in pollen increased, inducing programmed cell death as a key reason for reduced viability. Low recovery of biomaterials after cryopreservation is a bottleneck that limits the application of this technology. At present, the mechanism of viability decline after cryopreservation is not fully understood. In this study, the effects of nitric oxide (NO) on programmed cell death (PCD) and its relationship with viability were investigated, using Paeonia lactiflora 'Fen Yu Nu' pollen with significantly decreased viability after cryopreservation. The results showed that: the activity of caspase-3-like and caspase-9-like protease and the apoptosis rate of pollen cells were significantly increased, the expression level of the promoting PCD (pro-PCD) genes was up-regulated, while the expression level of the inhibiting PCD (anti-PCD) genes was down-regulated after preservation in liquid nitrogen (LN); the NO content in pollen cells increased significantly after LN exposure. The correlation analysis showed that NO was significantly correlated with pollen viability and all indicators of PCD. The addition of a NO carrier SNP after LN storage reduced pollen viability, increased endogenous NO content, decreased mitochondrial membrane potential level, activated caspase-3-like and caspase-9-like protease in pollen cells, and increased cell apoptosis rate. The expression levels of pro-PCD genes PDCD2 and ATG8CL were significantly up-regulated, while the expression levels of anti-PCD genes DAD1, BI-1 and LSD1 were significantly down-regulated. The addition of NO scavenger c-PTIO improved pollen viability, and produced the opposite effect of sodium nitroferricyanide (III) dihydrate (SNP), but did not change the mitochondrial membrane potential. These results suggest that NO induced PCD during the cryopreservation of pollen, which was one of the reasons for the significant decrease of pollen viability after cryopreservation.

Globalization has drastically reduced the number of autochthon apple cultivars in the Serbian market and most of them have nearly disappeared; however, some of these cultivars, such as Petrovača, Budimka, Kolačara Pozna, and Kožara, have extraordinary quality, good pomological characteristics, and pest and disease resistance. The present study was conducted to develop a protocol for the storage of pollen for further use in the conservation and breeding of these cultivars. Viability and germination of the mature pollen were tested in vitro, at four storage temperatures (20, 4, −20, and −80°C), right after harvest or 1, 2, 3, 4, 5, and 6 months after storage. Differences in fresh pollen viability and germination between cultivars were statistically significant and ranged from 60 to 88% and 59 to 98%, respectively. Fresh pollen of cv. Budimka showed the highest viability and germination in comparison with other cultivars, especially cv. Kožara. Pollen viability and germination decreased over the storage period, and it was the lowest after 6 months of storage at room temperature in all tested cultivars. Storage at 4°C prolonged the pollen viability and germinability of 1–5 fold, depending on the cultivar and treatment duration; however, the pollen longevity of all cultivars was significantly extended when stored at −20 or −80°C. After 6 months, pollen of cv. Budimka stored at −20 and −80°C showed 14–15 fold higher germination rates in relation to pollen storage at room temperature for the same period. The results of the present study suggest that the pollen of these apple cultivars could be efficiently maintained at −20°C and could be further used for breeding purposes, e.g., for crossings between cultivars that flower at different times of the year.

Elaeis oleifera chromosomes are similar to those of E. guineensis, with close gene pools for the production of interspecific O x G hybrids. The pollen viability and germination of E. oleifera ‘Coarí’ and E. guineensis ‘La Mé’ were compared to their interspecific hybrid O x G (‘Coarí’ x ‘La Mé’). The pollen viability was determined by the acetocarmine staining method (0.5 %) and the pollen germination by in vitro incubation on agar-sucrose medium (1.2-11.0 g in 100 mL of distilled water). The pollen viability and germination of the ‘Coarí’ x ‘La Mé’ hybrid were significantly lower than those of their parents. The percentage of pollen viability by acetocarmine staining was higher than that of in vitro germination, indicating that not all pollen grains classified as viable germinated on the agar-sucrose medium. The pollen germination test is a more reliable indicator than the staining viability test, because the latter only reveals that the pollen contains the enzymes necessary to initiate germination, while the germination test determines the emission and development of the pollen tube. RESUMO Os cromossomos de Elaeis oleifera são semelhantes aos de E. guineensis, com pools genéticos próximos para a produção de híbridos interespecíficos O x G. A viabilidade e germinação do pólen de E. oleifera ‘Coarí’ e E. guineensis ‘La Mé’ foram comparadas com as de seu híbrido interespecífico O x G (‘Coarí’ x ‘La Mé’). A viabilidade do pólen foi determinada pelo método de coloração com acetocarmina (0,5 %) e a germinação por incubação in vitro, em meio ágar-sacarose (1,2-11,0 g em 100 mL de água destilada). A viabilidade e germinação de pólen do híbrido ‘Coarí’ x ‘La Mé’ foram significativamente menores do que as de seus progenitores. A porcentagem de viabilidade do pólen pela coloração com acetocarmina foi superior à germinação in vitro, indicando que nem todos os grãos de pólen classificados como viáveis germinaram no meio ágar-sacarose. O teste de germinação de pólen é um indicador mais confiável que o de viabilidade por coloração, pois este apenas revela que o pólen contém as enzimas necessárias para iniciar a germinação, enquanto o teste de germinação determina a emissão e desenvolvimento do tubo polínico.

Low activity level of biomaterials after cryopreservation is a bottleneck problem that limited the application of this technology. At present, the mechanism of viability decline after cryopreservation is not fully understood. In this study, the effects of nitric oxide (NO) on programmed cell death (PCD) and its relationship with viability were investigated, using Paeonia lactiflora 'Fen Yu Nu' pollen with significantly decreased viability after cryopreservation. The results showed that: the activity of caspase-3-like and caspase-9-like protease and the apoptosis rate of pollen cells were significantly increased, the expression level of promoting PCD (pro-PCD) gene was up-regulated, while the expression level of inhibiting PCD (anti-PCD) gene was down-regulated after preserved in liquid nitrogen (LN); the NO content in pollen cells increased significantly after LN preserved. The results of correlation analysis showed that NO was significantly correlated with pollen viability and all indicators of PCD. The addition of NO carrier SNP after LN storage reduced pollen viability, increased endogenous NO content, decreased mitochondrial membrane potential level, activated caspase-3-like and caspase-9-like protease in pollen cells, and increased cell apoptosis rate, and the expression levels of pro-PCD genes PDCD2 and ATG8CL were significantly up-regulated, while the expression levels of anti-PCD genes DAD1, BI-1 and LSD1 were significantly down-regulated; and the addition of NO scavenger c-PTIO produced the opposite effect of SNP. It was suggested that NO induced the PCD during the cryopreservation of pollen, which was one of the reasons for the significant decrease of pollen viability after cryopreservation.

Rootstock can improve tree vigor, bloom period, fruit quality and yield of kinnow mandarin. The use of rootstock is a choice for improving the productivity. The aim of this two year study to find out the effect of rootstocks (Rough lemon, Carrizo citrange, Volkamer lemon, CRH-12, NRCC-1, NRCC-2, NRCC-3, NRCC-4, NRCC-5 and NRCC-6) on the flowering period, pollen viability and number of segment of kinnow mandarin. Kinnow started flowering 13th March on almost all rootstocks. However, trees on NRCC-1, NRCC-5 started flowering from 14th March. The earliest full bloom period was recorded on Carrizo, CRH-12 (17th -22th March). None of the rootstocks affects pollen viability significantly during the period of study.

The present study was focused on determining the effects of brassinosteroid, naphthalene acetic acid and gibberellic acid on in vitro pollen germination and pollen viability of tulip. Knowledge on different sources of pollen is an important issue for ornamental plant growers or breeders especially in crossing procedures for tulip. Flower bud formation and inflorescence is affected by bulb size, environment, irrigation, nutrition and many other factors. In some ornamental plants pollen quality as well as cultivar affect viability and germination characteristics. Tulipa greigii 'Pinocchio' was used as a pollen source which was tested for its ability to germinate in vitro on a medium (1% agar and 20% sucrose) containing three different group of hormones, gibberellic acid (GA3), naphthalene acetic acid (NAA) and epibrassinolide (EBR). After 24 h of incubation, pollen were evaluated and germination ratios were determined. The results indicate that pollen germination was significantly affected by growth regulators while pollen viability and germination rates were altered according to the concentrations and the type of the growth regulators. The highest average value of the pollen germination rate (42.95%) was determined in the concentration of 0.1 mg L(‑1) EBR treatment in Tulipa greigii 'Pinocchio', while the highest value (92.47%) for the pollen viability was obtained from epibrassinolide (EBR) in comparison to the other hormones.

Repetitive flower closure (nyctinasty) is influenced by various regulatory mechanisms, but its ultimate function remains unclear. It is hypothesized that closed corolla may protect a plant's reproductive organs against various unfavourable environmental conditions. We investigated if repetitive flower closure enhances pollen viability and prevents pollen loss in an early spring flowering species, Crocus discolor, occurring in open grasslands of submontane to subalpine zones of the Western Carpathian Mountains. Artificially interrupted temporal petal closure resulted in lower pollen viability, but it had no effect on the pollen availability in flowers. The latter result suggests that wind did not cause pollen loss from open flowers, but whether closed corolla may protect reproductive organs from being damaged by hail or rain remains to be tested. Closing corolla may serve as a pollen protection mechanism, particularly in early flowering plants facing harsh environmental conditions.

Damayanti F, Garvita RV, Wawangningrum H, Rahayu S. 2021. Flower development, pollen viability and pollen storage test of Aeschynanthus radicans. Biodiversitas 22: 1940-1945. Aeschynanthus radicans Jack. commonly-known as lipstick flowers, is an epiphytic plant in Gesneriaceae family. It has an attractive morphology and is easy to grow. Therefore A. radicans is used as mother species for hybridization by plant breeders. The flowers of A. radicans are dichogamous and strongly protandrous. The pollen matures before the stigma becomes receptive and bends away and down when the stigma becomes receptive. As a thought-after material for hybridization, little is known about the flower development, pollen viability, and storability. The purpose of this study was to observe the development phase of A.radicans flowers, determine the viability of pollen during flower development, and investigate the pollen storability at -20?C. Flower development was observed in phases from small buds to anthesis. Pollen viability was tested in 10%, 15%, and 20% sucrose solution for 4 hours. Pollen storage was tested at -20?C for 77 days and tested for viability every three weeks. The best sucrose concentration for the germination of fresh pollen was 20%. The highest pollen viability was at H0 was 58±3% and gradually decreased with flowerage. The lowest viability was 18±14% at flower stage H5, coinciding with the first day of stigma receptive. Pollen storage at -20?C decreased pollen viability to 30,2±2% after 42 days and to 13,54% after 77 days.

RESUMO O caquizeiro é uma planta muito complexa na questão de sua biologia floral, já que pode apresentar três tipos de flor (feminina, masculina ou hermafrodita) ou apenas flores femininas, como no caso das cultivares comerciais. O objetivo deste trabalho foi estudar o período de florescimento, os tipos de flores e estimar a viabilidade dos grãos de pólen em nove cultivares de D. kaki e em D. virginiana. As cultivares Pomelo e Rama Forte foram precoces para o início do florescimento. A cultivar Pomelo e a espécie D. virginiana apresentaram produção de flores masculinas, com pólen viável. As nove cultivares de D. kakiestudadas apresentaram produção de flores femininas (também masculinas em Pomelo) como esperado em cultivares comerciais. Porém a cultivar Mikado apresentou, ao final do florescimento, flores com produção de pólen viável, o que ainda não havia sido relatado. A viabilidade dos grãos de pólen, em geral, foi acima de 90% para as cultivares Pomelo e Mikado, e para D. virginiana. ABSTRACT Persimmon tree is a very complex plant regarding floral biology, because it can present three types of flower (female, male or hermaphrodite) or only female as in the commercial cultivars. The objective of this research was to study the flowering period, flower types and to estimate pollen grains viability in nine D. kaki cultivars and in D. virginiana. Cultivars Pomelo and Rama Forte were the earliest for flowering beginning. Cultivar Pomelo and D. virginiana produced male flowers with viable pollen. The nine studied D. kaki cultivars presented females flowers (also male in Pomelo) as expected in commercial cultivars. Unexpectedly, cultivar Mikado presented male flowers with viable pollen at the end of the flowering period, what had not been previously reported. Pollen viability was generally over 90% for Pomelo, Mikado and D. virginiana.

The way of improvement of the efficiency of white head cabbage pollination in case of low pollen viability is presented. The optimal culture medium with Tris maintaining pH 8$9 for germination of cabbage pollen was determined. Pollination of style by the suspension of pollen in the optimal culture medium was suggested. This method allows obtaining of seeds of doubled haploid plants with partially sterile pollen.

The work presents the results of determining the pollen viability and fertility of three species from genusHemerocallis in the forest-steppe zone of Western Siberia. It was noted that H. middendorfii has the most viable pollen,while its value is quite low and amounts to only 5 %. In other species, the maximum value of this indicator varies from 1.9% (H. citrina) to 4.6 % (H. fulva). It was established that the pollen of studied species has a rather high degree of fertilityand takes values from 50.8–56.2 % of H. fulva to 93.4–95.7 % of H. middendorfii.

In the past decades, tomato (Solanum lycopersicum L.) hybrid seed production has been massively employed in breeding programs throughout the world. However, some important physiological factors should be considered in order to attain adequate yield in association with high physiological and genetic qualities, during hybrid seed production. Pollen viability under stored conditions is of crucial importance or hybrid seed production as well as co-hybrid development programs and collaborative shuttle breeding networks among partner research institutions/companies. The main objective of the present work was to identify the best combinations of temperature and storage time of tomato pollen grains aiming to produce hybrid seeds with high genetic and physiological qualities. Pollen grain viability of the male tomato inbred line of the hybrid 'San Vito' (San Marzano type) was evaluated after the following storage conditions: 4, -20, and -80°C in combination with 30, 60, and 120 days of pollen storage. The viability of the pollen grains was evaluated by visualizing them in vivo through stigma tissue and counting the percentage of grains with conspicuous pollen tube growth (germination). The results indicated that the best storage condition for the tomato pollen was -20°C for 60 days. Under this storage condition, the average pollen germination was around 41%. These results reinforce that storage at low temperatures might represent an alternative technique for tomato pollen conservation, assisting the hybrid seed production systems and minimizing the risk associated with the potential lack of flowering synchronization between male and female parental inbred lines.

The causes of fruit abortion, in eggplants, may be related to the absence of viable pollen under high temperatures, common in the Northeast region of Brazil, resulting in a reduction in the number of fruits per plant and consequently in productivity. The objective of this study was to evaluate the techniques of identification of PV – pollen viability in eggplant, as well as to correlate these results with the FFI – Fruit Fixation Index, NFP – Number of Fruits per Plant and PP – Production per Plant obtained in cultivation under high temperatures. The experiment was conducted at the Federal Rural University of Pernambuco, Recife, Brazil, between September and December 2017. The experiment design was a randomized block design with four replications, in the 7 x 4 factorial scheme (7 genotypes x 4 evaluation of PV) containing four plants per experimental plot. The results showed that the different techniques used detected viable pollens in the genotypes evaluated in smaller and in larger proportions. The highest percentages were observed in the treatments with CA – Carmine Acetic and AS – Alexander Solution and these overestimated the PV (>90%). In the test with TTC – 2,3,5-triphenyltetrazolium chloride (25%), the viability estimation was equivalent to the in vitro germination test, however the genetic correlations were null and/or very low between these techniques and the FFI, NFP and PP traits. The genetic correlations between the results obtained with CA and AS with FFI, NFP and PP under conditions of high temperatures were high and positive and suggest that the selection based on PV only, except with the use of TTC solution, may be efficient for indirect selection of genotypes with high FFI, NFP and PP.

The genus Hydrangea L. is comprised of some of the most popular ornamental plants in the world. The development of interspecific hybrids between Hydrangea species and within the family Hydrangeaceae would increase genetic diversity in the Hydrangea breeding pool and lead to unique combinations of desirable traits. Protocols to estimate Hydrangea pollen viability need to be optimized in order to perform basic studies on self- and cross-incompatibility, fertility of hybrids, formation of unreduced gametes, and pollen storage. Our goal is to quantify pollen production in Dichroa, Hydrangea, and their hybrids, determine the optimal media for pollen germination, and develop a series of correlations between staining and germinating that can be applied to stained pollen for a rapid, precise estimate of viability. Production of round versus oblong pollen grains was heavily influenced by species (F = 335.8, p

Foliar sprays with gibberellic acid (GA) and silver nitrate (AgNO3) of di erent concentra ons at pre-flowering stage induced hermaphrodite and male owers on strictly gynoecious vines of teasle gourd (Momordica subangulata Blume. subsp. renigera). GA at 1500 ppm and AgNO3at 500 ppm were effective inducing more than 50% male owers in the female clone “Mondouri local”. AgNO3 at 750 ppm was effective in inducing 36.6% male and 33.9% hermaphrodite owers on same plant. The hermaphrodite ower had higher pollen size (103.57 μm) compared to that of natural male ower (94.94 μm). However, there existed no variation between pollen viability of bisexual ower (81.6%) and normal male ower (89.1%). However, germinability of the pollen of hermaphrodite ower was very low (14.16%) producing very small pollen tube (9 μm), though the bisexual ower did not produce any fruit on self-pollination.

Cryopreservation minimizes the risk of losing valuable accessions and reduces the material costs of plant resources maintenance. By using the method of pollen long-term storage in cryobanks, it is possible to keep pollen grains viable for an unlimited time. In the course of the research, cryoconservation of pollen of stone fruit crops was performed and pollen viability was checked after exposure to ultra-low temperatures (-196°С) under laboratory conditions. The studies were carried out on apricot (Armeniaca vulgaris Lam.) and sweet cherry (Cerasus avium (L.) Moench) plants, from which pollen was collected. Evaluation of viability in laboratory conditions was carried out by germination on various nutrient media. The possibility of long-term pollen preservation in liquid nitrogen vapor is shown. Based on the results obtained, a collection of pollen is being created for implementing various breeding programs.