Pollen Viability and Germinability of Gamma Irradiated M4 Lines of Sesame

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.

Ploidy and Genome Size in Lilac Species, Cultivars, and Interploid Hybrids

Genome size variation can be used to investigate biodiversity, genome evolution, and taxonomic relationships among related taxa. Plant breeders use genome size variation to identify parents useful for breeding sterile or improved ornamentals. Lilacs (Syringa) are deciduous trees and shrubs valued for their fragrant spring and summer flowers. The genus is divided into six series: Syringa (Vulgares), Pinnatifoliae, Ligustrae, Ligustrina, Pubescentes, and Villosae. Reports conflict on genome evolution, base chromosome number, and polyploidy in lilac. The purpose of this study was to investigate genome size and ploidy variation across a diverse collection. Flow cytometry was used to estimate monoploid (1Cx) and holoploid (2C) genome sizes in series, species, cultivars, and seedlings from parents with three ploidy combinations: 2x x 2x, 2x x 3x, and 3x x 2x. Pollen diameter was measured to investigate the frequency of unreduced gametes in diploid and triploid Syringa vulgaris cultivars. Three triploids of S. vulgaris were observed: ‘Aucubaefolia’, ‘Agincourt Beauty’, and ‘President Grévy’. Across taxa, significant variations in 1Cx genome size were discovered. The smallest and largest values were found in the interspecific hybrids S. ×laciniata (1.32 ± 0.04 pg) and S. ×hyacinthiflora ‘Old Glory’ (1.78 ± 0.05), both of which are in series Syringa. Series Syringa (1.68 ± 0.02 pg) had a significantly larger 1Cx genome size than the other series. No significant differences were found within series Pubescentes (1.47 ± 0.01 pg), Villosae (1.55 ± 0.02 pg), Ligustrina (1.49 ± 0.05 pg), and Pinnatifoliae (1.52 ± 0.02 pg). For S. vulgaris crosses, no significant variation in 2C genome size was discovered in 2x x 2x crosses. Interploid crosses between ‘Blue Skies’ (2x) and ‘President Grévy’ (3x) produced an aneuploid population with variable 2C genome sizes ranging from 3.41 ± 0.03 to 4.35 ± 0.03 pg. Only one viable seedling was recovered from a cross combination between ‘President Grévy’ (3x) and ‘Sensation’ (2x). This seedling had a larger 2C genome size (5.65 ± 0.02 pg) than either parent and the largest 2C genome size currently reported in lilac. ‘Sensation’ produced 8.5% unreduced pollen, which we inferred was responsible for the increased genome size. No unreduced pollen was discovered in the other diploids examined. Increased ploidy may provide a mechanism for recovering progeny from incompatible taxa in lilac breeding.

MICROMORPHOLOGICAL FEATURES OF THE NARROW ENDEMIC SILENE SYTNIKII (CARYOPHYLLACEAE) COMPARED WITH CLOSELY RELATED SPECIES

Silene sytnikii Krytzka, Novosad et Protopopova is a local endemic species of the Ukrainian flora, which sometimes is considered as a synonym to the S. frivaldszkyana Hampe from the Balkans and is related to the widespread species S. chlorantha (Willd.) Ehrh. The aim of the present study is to investigate micromorphological features of seeds, pollen grains and leaf surface ultrastructure of foregoing species and make a comparison. Both light and scanning electron microscopy were used in the study. S. sytnikii and S. frivaldszkyana are slightly different in the size of exotesta cells and their anticlinal teeth in distal row of seeds, pollen diameter and microechinate number on the pore, size of leaf spinule, epidermal cells and stomata. S. chlorantha significantly differs from them by smaller seeds and exotesta cells, and also longer leaf spinules. Thus, S. sytnikii and S. frivaldszkyana are quite similar in their micromorphology, while S. chlorantha is clearly distinct from them.

Respon Perkecambahan Polen Pepaya IPB 6 dan IPB 9 terhadap Penyimpanan pada Suhu Rendah

<p>ABSTRACT</p><p>An experiment was conducted to study the germination and storability of papaya pollen IPB 6 and IPB 9 stored for 4 weeks at 3 levels of low temperature. The experiment was conducted at the Laboratory of Microtechnic and Laboratory of Biophysics and Reproductive Biology, Bogor Agricultural University in the month of April to June 2014. Three variables were observed in this experiment: the germination rate, pollen diameter, and length of pollen. The experimental results showed that storage temperature affected the three variables observed. The best germination for IPB 6 was indicated by pollen storage at 10 0C (23.1%) while for IPB 9 was indicated by pollen stored at 5 0C (30.7%). The longest pollen tube of IPB 6 after storage for 4 weeks was indicated by pollen stored at -20 0C (63 µm) while for IPB 9, indicated by pollen stored at 10 0C (47.72 µm). The experimental results showed that there was no corellation between pollen diameter and length of pollen tube with pollen germination in papaya pollen of IPB 6 dan IPB 9.</p><p>Key words: diameter pollen, pollen tube, germination, storability</p><p> </p><p>ABSTRAK</p><p>Percobaan dilakukan untuk mempelajari daya simpan dan daya berkecambah polen pepaya IPB 6 dan IPB 9 yang disimpan pada suhu 5 0C, 10 0C, dan -20 0C dengan waktu penyimpanan 0-4 minggu. Percobaan dilaksanakan di Laboratorium Mikroteknik dan Laboratorium Biofisik dan Biologi Reproduksi, Institut Pertanian Bogor pada bulan April-Juni 2014. Tiga variabel yang diamati pada percobaan ini adalah daya berkecambah, diameter polen dan panjang polen. Hasil percobaan menunjukkan bahwa suhu penyimpanan mempengaruhi ketiga variabel yang diamati. Daya berkecambah terbaik untuk pepaya IPB 6 ditunjukkan oleh polen yang disimpan pada 10 0C (23.1%)sedangkan untuk IPB 9 ditunjukkan oleh polen yang disimpan pada 5 0C (30.7%). Tabung Polen pepaya terpanjang setelah disimpan selama 4 minggu pada IPB 6 ditunjukkan oleh polen yang disimpan pada -20 0C (63 µm) sedangkan untuk IPB 9 ditunjukkan oleh polen yang disimpan pada 10 0C (47.72 µm). Hasil percobaan menunjukkan bahwa tidak ada hubungan antara diameter dan panjang tabung polen dengan daya berkecambah pada polen pepaya IPB 9 dan IPB 6.</p><p>Kata kunci: daya berkecambah, daya simpan, diameter polen, tabung polen</p>

Palynomorphological study of Dianthus petraeus waldst. et kit. (Caryophyllaceae)

The pollen morphology of Dianthus petraeus (Caryophyllaceae), which is endemic to the Balkans, has been examined by both light and scanning electron microscopy in order to provide taxonomically valuable characters that might be used in the classification of the Caryophyllaceae, as well as to contribute to the pollen atlas of Serbian apiflora. The pollen grains of D. petraeus are radially symmetrical, apolar, spheroidal and medium-sized. The mean of the pollen diameter is 45.5?1.4 ?m. The sculpturing pattern of exine is microechinate-microperforate, and the tectum is covered with minute echini averaging 0.8?0.1 ?m in length, more or less evenly distributed between the perforations. The microechini average number per sample area of 5 ?m x 5 ?m is 3.2?0.6. In view of the number, position and type of the apertures, the grains are polypantoporate, with about 13 operculate pores, averaging 6.4?0.7 ?m in diameter. Each operculum is covered with 4-6 conical spinules, which are longer than those on the exine surface. The mean interporal distance is 13.3?1.3 ?m. The obtained palynological results provide information that contribute towards a better understanding of the taxonomic status of D. petraeus.

Badania nad pyłkiem potomstwa brzozy ojcowskiej Betula oycoviensis [Investigations on the pollen of the progeny of Betula oycoviensis Basser]

Several crossings have been executed, of which it results that the progeny of <em>Betula oycomensis</em> pollinated by <em>Betula oycoviensis</em> segregates into three groups: the type <em>oycoviensis</em>, type <em>verrucosa</em> and type <em>„nova"</em>. The two formes occur as trees, the last mentioned is a small shrub. It has been established that the arithmetic means of the pollen diameter of the three types of birches hardly differed among themselves. As regards the degree of development, there were only very slight differences between the particular types within one generation and between generations. On the other hand, there were fairly great individual differences among the particular specimens as regards the size and degree of development of the pollen grains. These values underwent changes from year to year.

Pollen Morphology and Viability Relates to Seed Production in Hybrid Roses

ABSTRACT Fertility of hybrid tea roses is often reduced due to their interspesific origin but also to intensive inbreeding. New genotypes used as pollen donors represent an economic risk for a breeding program, as their influence on seed production is unknown. In this study 9 garden rose genotypes were selected from a company database as high fertile or low fertile male parents, according to the number of seeds per hybridization. Pollen morphology and in vitro germination of the selected genotypes were characterized. Pollen was either small (mean diameter = 30 urn), shrunken, and irregular (abnormal), or large (mean diameter = 30 urn), elliptical and crossed by furrows (normal). High correlations were found between the number of seeds produced per hybridization and the pollen diameter (r = 0.94) or the percentage of normal pollen (r = 0.96). In order to evaluate the predictive power of the models, we conducted regression analyses and performed a validation experiment on genotypes not present in the database and without background information on fertility. Pollen diameter and percentage of normal pollen were characterized and fitted in the regression models for seed set predictions. Validation with an independent dataset gave a good prediction for 83.3% of the data. This indicates that using either the mean pollen diameter or the percentage of normal pollen resulted in effective fertility prediction. Moreover cluster analysis of the data classified all the cultivars into various groups with varying fertility. This tool could enhance the genetic variability in crossings between hybrid tea roses, thus creating possibilities for less economically risky exploitation of new tetraploid genotypes as male parents.

Some cytological, ecological and evolutionary aspects of pollination

Different types of pollen dispersing units are described. The pollen of angiosperms may be dispersed in monads, tetrads, polyads, massulae or compact pollinia. The monads and tetrads may form larger clumps of pollen with the aid of the following substances: a) pollenkitt, a product of <em>in situ</em> degeneration of the tapetum; b) tryphine, a product of tapetal extra situm degeneration, found only in <em>Cruciferae</em>; c) elastoviscin, a highly viscous product of the degeneration of a limited number of tapetal cells, found only in certain <em>Orchidaceae</em>; d) viscin threads or sporopollenin filaments arising from the pollen exine. The number of pollen grains composing the clumps depends on pollen diameter and the cohesive forces holding the pollen grains together. The various types of pollen dispersing unit are discussed in relation to the type of pollination and number of ovules per ovary.

Production of Amphidiploids of the Hybrids between Solanum macrocarpon and Eggplant

To restore fertility of the F1 between Solanum macrocarpon and eggplant, amphidiploids were produced through doubling of chromosomes by colchicine treatment. Shoot tips and axillary buds of F1 plants were kept for 2 and 4 days in liquid Murashige and Skoog (MS) media with 0.05% colchicine. As a result of colchicine treatment, two amphidiploids were identified by observing root tip cell chromosome number, stomatal guard cell size, and pollen characteristics. The amphidiploids contained 48 chromosomes, twice the normal diploid number of 24. Stomata size and pollen diameter were significantly larger in amphidiploids than F1. Flower diameter and length and width of anther, petal, and sepal were significantly larger in the amphidiploids than in F1. Pollen stainability was 40% in amphidiploids but only 0.86% in the diploid F1. The amphidiploids, after selfing and backcrossing with S. macrocarpon, set fruits with healthy seeds. Therefore, production of amphidiploids by colchicine treatment restored the pollen and seed fertility of F1 between S. macrocarpon and eggplant. The amphidiploids produced in this study would be very useful in future breeding programs of eggplant.

PHENOTYPIC FEATURES OF CMS IN SEED-BEARING PLANTS OF RED BEET

Phenotypic characteristics defining the CMS in plants of red beet have been studied. The level of sterility varied from 5 to 100 %. Four groups of anthers were sorted out where each group distinguished by certain color, diameter, the number and size of pollen grains inside. The increase of sterility of plants provoked the decrease of pollen diameter, pollen viability in fertile flowers; along this the speed of pollen tube growth is reduced.