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Potato has about 100 related wild Solanum species growing naturally in the Americas. Solanum jamesii (jam), native to the southwest USA and Mexico, has many valuable traits for breeding, but making hybrids is extremely difficult. We investigated the approach of using the bridge species Solanum verrucosum (ver). A survey of all ver populations in the US Potato Genebank identified the best females. The standard bridge crossing technique using emasculation of ver and “mentor” double pollination after first pollinating with jam was very inefficient for most ver because: 1) emasculation depressed seedset in ver females, 2) despite very careful emasculation many accidental ver selfs resulted, and 3) mentor pollination produced many unwanted hybrids with the mentor pollen parent. We therefore produced populations of ver by backcrossing five generations into tuberosum cytoplasm. The BC5 lines are very vigorous in growth and flowering, but having very low male fertility and complete self-incompatibility they can be mass crossed with jam pollen without emasculation. Even with no mentor pollen, most pistils of verBC5 pollinated with jam produce a small fruit with an average of less than one normal seed. Resulting seedlings were confirmed ver-jam hybrids by DNA markers.

The potato crop has much exotic related germplasm, so optimizing the techniques for obtaining hybrid seeds from interspecific crosses is of interest to potato researchers and breeders, especially when the cross of interest is very difficult and few hybrid seeds are expected per pollination. A model plant of Solanum verrucosum (a particularly useful wild bridge species) was selected to have very uniform and robust flower and seed production in natural crosses as a backdrop for detecting effects of different emasculation techniques. For three uniform buds in single inflorescences, one was pollinated naturally (N) after no emasculation, one was emasculated by gently opening the corolla and plucking out only the immature anthers (A) with a tweezer, and one had total (T) removal of the sepals, corolla and anthers with a tweezers. Pollen of a highly fertile diploid tuberosum male was applied uniformly to all three buds within an inflorescence one day later. No pistil abortion occurred, excluding that as a limiting factor for getting hybrid seed. But both average fruit weight and average seeds per fruit were highly significantly reduced by emasculation in the pattern T

Proso millet and Little millet belong to group of small millets and family poaceae. Flower opening in these crops are chasmogamous type, in which pollination takes place prior to opening of flowers. Hence, self pollination predominates. So, to create variability, hybridization is prerequisite. Because of self pollination and non availability of male sterility, emasculation is necessary for crossing. There are many emasculation and crossing methods like contact method, hot water treatment, hand emasculation and USSR method which are used in these crops. But the disadvantage in these methods is damage to stigma this reduces the success rate of obtaining true F1’s. To overcome all these problems of earlier methods, in our present study, we proposed the modified crossing (SMUASB) method. In this method, cold water of 5–8°C is sprayed on the panicle as a mechanical stimulator for opening of florets in male and female panicles. For emasculation, female panicle is gently washed in cold water. This will not affect stigma and its receptivity. All florets which are already fertilized and not opened immature florets are removed before pollination. Hence, success rate of obtaining true F1s is more and less land and resources are required for evaluation of F1’s. Using SMUASB method, we attempted crosses in Little millet and Proso millet and the success rate observed was 56% and 60% respectively.

Productivity of hybrid cottonseed by steady male sterile line is considered as an effective strategy in heterosis utilization. The male sterility was obtained by glyphosate application on transgenic glyphosate-tolerant (TGT) cotton line GRR, and its phenotypes were stable and apparent from previous primarily study. Systematic characterizations and safety assessments on the male sterility must accelerate its utilization and release in hybrid cottonseeds productions. In this study, featured characteristics in the male sterility were revealed from morphological phenotype, microsporogenesis, expressing pattern of exogenous G6-EPSPS mRNA, antioxidant enzymes response. Additionally, safety assessments on the male sterility obtained from GRR, based on outcrossing rate test, yield and fiber quality traits, in comparison with conventional manual emasculating, which were conducted for 3 seasons. The results indicated that the male sterile is stable with typical characteristics as following: (1) shorter and fusion filaments, larger distance between androecium and stigma, and anther indehiscence; (2) pre-degradation on tapetum and “cavitation” pollen during microsporogenesis; (3) Higher increasing expression efficiency of G6-EPSPS, as much as approximate 8 times, in pistil versus stamen in GRR-GT (GRR after glyphosate) was revealed, comparing with the control GRR (4) APX activity increased in stamens while decreased in other organs, in GRR-GT versus GRR. GRR-GT is safe as complete abortion and capable in cotton heterosis utilization, since there were no negative effects on F1 yield traits and significance in fiber quality parameters, in comparison with conventional manual emasculation. In details, the all fiber lint yields and Micronaire values ranged from 1536.80 ± 115.64 to 1883.90 ± 18.58 kg/ha and 4.60 ± 0.10 to 5.10 ± 0.79 respectively.

An effective male sterility system enables targeted crosses between parent plants with desired and complementary characteristics. The use of chemical hybridising agents (CHAs) to induce male sterility is quicker and more efficient than manual emasculation. This study investigated the concentration, stage of application and frequency of application of ethyl 4'fluorooxanilate (E4FO) for inducing male sterility of sweet stem sorghum without affecting female fertility. In Trial 1, the dose rate of E4FO was determined to optimise male sterility. In this experiment three genotypes were tested at E4FO dose rates. In Trial 2 the frequency of application of E4FO was determined using three sweet stem sorghum genotypes, three E4FO doses, and six frequencies of application. Data on sterility was inferred based on seed set and seed count from the treated plants. Male sterility was achieved when E4FO was applied during heading stage using the following rates: 1 g l−1, 1.5 g l−1 and 2 g l−1, with more than one a...

Owing to their superior agronomic performance, the hybrids of vegetable crops are currently applied extensively. However, effective hybrid production requires a laborious manual emasculation to ensure the purity of hybrid seeds in tomato because of the lack of an effective male sterility system. Here, we created two types of tomato nuclear male-sterile lines with different screening markers in a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system. Co-knockouts of male sterile 10(35) (Ms10(35)) and glutathione S-transferase (GSTAA) created a male-sterile line marked by a green hypocotyl. The Ms10(35) biallelic mutation was introduced into the woolly tomato background, resulting in the linkage of male sterility and a non-woolly phenotype. Two types of male-sterile lines were easily selected at the seedling stage by hypocotyl color or trichome density and further showed high seed purity during hybrid seed production. Our work established the procedure for a rapid transfer of the male-sterile phenotype to the parents of hybrids without extra-modification by the CRISPR/Cas9 system that can be practically applied to hybrid seed production in tomato. This method will be the basis and example for sterile parent creation of multiple crops for hybrid production with the CRISPR/Cas9 system. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11032-021-01215-2.

Citrus reproductive biology is complex. One of its characteristic features is parthenocarpy that enables seedless fruit production. Citrus parthenocarpy and self-incompatibility knowledge is only partial and sometimes discrepant. Increasing such knowledge is relevant for better managing cultivated varieties and improving the selection of parents in breeding strategies to recover seedless varieties such as mandarins. This work develops an efficient protocol to characterize self-incompatibility and different parthenocarpy types based on emasculation, hand self-pollination, and hand cross-pollination. It analyzes fruit setting and seed production coupled with histological pollen performance observations. We analyzed the reproductive behavior of nine mandarin varieties with relevant characteristics as parents for seedless mandarin breeding. ‘Clemenules’ clementine and ‘Moncada’ mandarins were strictly self-incompatible with facultative and vegetative parthenocarpy, ‘Imperial’ mandarin and ‘Ellendale’ tangor displayed no strict self-incompatibility associated with facultative and vegetative parthenocarpy, ‘Fortune’ mandarin was self-incompatible with facultative and stimulative parthenocarpy, ‘Campeona’ and ‘Salteñita’ mandarins were self-compatible with vegetative parthenocarpy, ‘Serafines’ satsuma was associated with male sterility together with facultative and vegetative parthenocarpy, and ‘Monreal’ clementine was self-compatible and nonparthenocarpic. Our protocol can be applied for screening of mandarin germplasm and to characterize new parents. Reproductive behavior knowledge is important for optimizing seedless mandarin breeding programs based on diploidy, triploidy, or induced mutagenesis.

Cultivated melons have spread through trade and exploration from centers of origin in Asia to Europe and the Americas and are important in local, regional and world trade. Iran ranks second in world melon production (Cucumis melo L.), generating over 1.7 million mt in 2018. Local farmers prefer to cultivate melon groups based on yield, fruit sweetness, firmness and color. However, some groups like Dudaim and Flexuosus have high fragrance and adaptation to warm and dry season; and are distributed in different culture regions. Since standard melon cultivars have evolved and been introduced, most commercial types exhibit variable, late female flower production and, consequently, late fruit ripening which are encountered with unfavorable condition of late season ripening, disease susceptibility and cucurbit fly as a critical problem of field melon production. Melons are cross-pollinated crops without inbreeding depression and are well suited to heterosis breeding. Furthermore, access to monoecious or gynoecious lines in commercial and popular melons with andromonoecious sex expression could reduce time and cost for emasculation and accelerate hybrid production. Priority of melon breeding should be given to produce multiple disease resistance, fruit size and uniformity, fruit quality attributes (color, mild aroma, firmness, thickness) and good shelf life for storage to reduced postharvest loss. This chapter reviews and explores the past, present and future prospect of melon breeding relative to Flexuosus and Dudaim Groups as genetic resources, flower and fruit attributes and also organic volatile compounds.

[EN] Cultivar Macabeo is one of the most planted white grape varieties of northern Spain. A general agreement supports many Vitis vinifera cultivars possibly being self-fertile, although this seems to be a variety-dependent characteristic. No previous information about the mating system of cv. Macabeo was found. This study aimed to analyze its mating system and to compare the in vivo fertilization process with and without artificial cross-pollination. Two treatments were performed: emasculation and cross-pollination. The seed number was counted, and pollen tube growth was observed by microscopy. The results showed that cv. Macabeo is self-fertile and selfing probably occurs before the flower opens. Pollen was found over the stigma of flowers before capfall and ovule fertilization was observed even in emasculated flowers, which suggests that germination and pollen tube growth happened in a very early flower development stage. Cross-pollination increased the presence of the pollen tubes growing inside flowers but was not necessary for fruit set. Ovule fertilization was very fast as 24 h (h) were enough for pollen tubes to reach the end of stylar canals., This research was supported by the Asociacion Club de Variedades Vegetales Protegidas as part of a project undertaken with the Universitat Politecnica de Valencia (Spain, UPV 20190822), of which H. Merle was the principal researcher. There was no additional external funding received for this study.

Baby corn has become a popular dietary choice worldwide. Here, we evaluated the potential of different male sterility systems as a tool to save cost for manual detasseling in baby corn. 24 hybrids having fertile (N-) and different sterile (T-, C- and S-) cytoplasms were analyzed for pollen sterility and various baby corn traits under three dates of sowing. ANOVA revealed significant genetic variation for number of baby corn ears, baby corn yield, length and width of baby corn ears, fodder weight and silking time. Cytoplasm and date of sowing caused significant variation for majority of baby corn characters. All the T-cytoplasm based hybrids showed no exertion of anthers and complete sterility except in one combination. C-cytoplasm based hybrids showed no to partial anther exertion and complete sterility to partial fertility of pollen. The S-type cytoplasm was quite unstable and showed partial to complete anther exertion and pollen fertility. Across hybrids and sowing time, T-cytoplasm had the highest number of baby corn ears per plot (61.83) and baby corn weight (2659.61 kg/ha) than C-cytoplasm (58.61, 2460.17 kg/ha), N-cytoplasm (57.39, 2323.08 kg/ha) and S-cytoplasm (56.83, 2301.89 kg/ha). The highest baby corn ear -length (8.82 cm), -diameter (1.48 cm), and fodder weight (35.07 t/ha) were recorded in T-cytoplasm. Late sowing had positive effects on baby corn over early planting. This information provides great significance for the utilization of male sterility in baby corn breeding. This is the first report on effects of different male sterility systems as a potential genetic emasculation mechanism in baby corn cultivation.

Prickly pear (Opuntia ficus-indica (L.) Mill. 1768) is cultivated in several dry and semi-dry areas of the world to produce fresh fruit, bioenergy, cosmetics, medicine, and forage. One of the main production constraints is the presence of many seeds within the fruit, which can negatively influence both the fresh-fruit market price and industrial transformation processes. In this study, different gibberellic acid (GA3) concentrations were tested for their ability to produce well-formed and seedless fruits. Different application methods (injection and spraying) and concentrations of GA3 (0, 100, 200, 250, and 500 ppm) combined with floral-bud emasculation were applied to a commercial plantation in southern Italy to evaluate their effects on the weight, length, and diameter of the fruits, total seed number, hard-coated viable seed number, and seed weight per fruit. The results indicated that the application of 500 ppm GA3 sprayed on emasculated floral buds was the most effective method for reducing seed numbers of prickly pear fruits (&minus, 46.0%). The injection method resulted in a very low number of seeds (&minus, 50.7%) but produced unmarketable fruit. Observed trends suggest the need to investigate the impact of higher GA3 concentrations and the applicability of a maximum threshold. Further studies are needed to increase our understanding of the physiological effects of the gibberellic acid pathway through productive tissue in terms of organoleptic and fruit quality.

Distant hybridization can enrich the genetic background and diversity of crops by combining different species, and integrate the favorable parental traits or create heterosis. In the present study, intergeneric hybridization was performed between radish and turnip and between radish and Chinese kale by hand emasculation followed by tissue culture of putative hybrid seeds. A total of three and one hybrids were obtained from the cross of ‘Long yellow turnip’ and ‘Golden turnip’ with radish, respectively, but no hybrids were obtained in their reverse cross, indicating that the same cross combination has a large difference in the reciprocal crosses, and that the hybrid has certain unidirectionality. The majority of the hybrids of radish and turnip showed male sterility, white petals, and intermediate performance in most morphological traits when compared to their parents. Four true hybrids were obtained by the cross ‘Thin neck round radish’ × ‘Yellow flower kale’, while no hybrids were obtained by reverse cross combination. The hybrids looked more like their Chinese kale parents in having inflated stems. All putative intergeneric hybrids were confirmed by agronomic characteristics, chromosome counting, molecular markers, and pollen viability. Three kinds of hybrids were confirmed as genuine hybrids possessing 19, 19, and 18 chromosomes in their corresponding somatic cells by cytological observation. In addition, three kinds of allotetraploids were produced with 38, 38, and 36 chromosomes when chromosome doubling was achieved. In comparison with the diploid hybrid, the pollen viabilities of allotetraploids were significantly improved and a small number of seeds were produced. The improvements of these amphihaploids as useful genetic resources and the potential of intergeneric hybridization to enlarge the gene pool for radish, turnip, and Chinese kale breeding are discussed.

The heat- and drought-sensitive highbush blueberry (Vaccinium corymbosum, section Cyanococcus; hereafter referred to as cor), is one of the main cultivated species of blueberry. In contrast, Vaccinium boninense (bon) and Vaccinium wrightii (wri), in the Bracteata section, are native to subtropical Asia, including Japan. The development of new blueberry cultivars combining the qualities of these species is of considerable interest at present. However, it is difficult to obtain hybrids between species from different sections or with different ploidy levels. Furthermore, our earlier attempt to cross cor with bon and wri did not produce any hybrids ( Miyashita, 2017 ). We hypothesized that the rate of success of interspecific hybridization in Vaccinium is reduced by emasculation, which is commonly performed before pollination. Therefore, the present study aimed to evaluate the crossability between cor and the diploid wild species (bon and wri) and to produce new intersectional hybrids. We made 15 combination crosses between six types of Vaccinium plants, including cor, bon, and wri (five species and an interspecific hybrid), with two crossing methods (emasculation and non-emasculation) for each combination included prior to pollination. The hybridity of the resulting seedlings was identified by polymorphism analysis using simple sequence repeat markers for blueberry. Hybrids were obtained from 10 of the 15 combinations. All these combinations were of the cross type such that both parental section and ploidy level were same, or that either section or ploidy level were different. In seven of the 10 combinations, hybrids were obtained only with the non-emasculation method. However, four combinations of the cross type where both section and ploidy level differed between parents failed to produce any hybrids. These results suggested that intersectional interploid cross type has lower crossability than that of either intersectional or interploid type, and that the non-emasculation method is more effective than the conventional emasculation method to obtain hybrids. However, the non-emasculation crossing did not prevent the production of nonhybrid seedlings, indicating the need to confirm the hybridity of each seedling. Subsequently, six reciprocal cross combinations between cor and the three polyploid or hybrid plants derived from bon and wri were made using the non-emasculation method. This yielded six hybrids from two combinations. To our knowledge, these are the first hybrids derived from cor and two Bracteata species native to subtropical Asia. These hybrids might be useful as breeding materials to enhance heat and drought tolerance in highbush blueberry.

The aim of this study was to determine the effect of selected factors on rye (Secale cereale L.) haploid embryo production by the wide crossing method. The study was performed on fifteen winter rye genotypes. This is the first time for rye when besides the genotype, on the enlargement of ovaries and haploid embryo production, such factors as: type of auxin analogues 2,4-dichlorophenoxyacetic acid (2,4-D), 3,6-dichloro-2-methoxybenzoic acid (dicamba) and 4-amino-3,5,6-trichloropyridine-2-carboxylic acid (picloram), and the time between florets emasculation and pollination were investigated. All factors had a significant impact on rye ovary enlargement, however the haploid embryo formation depended only on rye genotype, not on kind of auxin and days between emasculation to pollination. In total, twenty one haploid embryos were formed by six genotypes of fifteen tested. On average, 13.86% (after 2,4-D treatment) to 20.05% (after dicamba treatment) enlarged ovaries per emasculated florets were obtained. Most of the ovaries enlarged when florets were pollinated 4 and 6 days after emasculation. Most of the haploid embryos formed when florets were pollinated 6 days after emasculation. The obtained haploid embryos did not germinate.

Cynara cardunculus L., member of the Asteraceae family, includes three botanical varieties, fully-inter-fertile: scolymus (globe artichoke), altilis (cultivated cardoon) and sylvestris (wild cardoon).The artichoke production is traditionally carried out through vegetative propagation using offshoots or suckers. However, several new seed propagated cultivars have been developed in recent years, which showed high yield and ruled out phytosanitary problems inherent to vegetative propagation. In this context, hybrid seeds production, which exploits the heterosis phenomenon producing high performance plants, is of global interest. Manual emasculation is extremely difficult; therefore, it is essential to have a male-sterility system to achieve an efficient hybrids production. In Cynara genus, genic male sterility was found only in globe artichoke but the genetic bases of this phenomenon is poorly explored. The objective of this work was to elucidate the genetic male sterility in Cynara cardunculus L. combining SRAP technology and a BSA approach and to identify molecular markers associated to ms genes, feasible to be applied for MAS in breeding programs of the species. Segregation of the male sterility in our F2 population fit to a monogenic segregation model (3:1), revealing that only one gene (ms) is responsible, in homozygous recessive stage, to determine male sterile plants. Three SRAP markers linked to the ms gene were found. The nearest marker (SRAP 7-10.1774) was estimated to be 0.5 cM from the ms gene whereas the others (SRAP 4-9.332 and SRAP 4-9.700) were linked at 4.3 cM and 13.9 cM, respectively.

Melastoma malabthricum is the type with the widest area of spread compared with other species in the genus Melastoma. This research uses floral phenology observation method and pollination experiment by using bagging technique, emasculation and artificial pollination. Stigma receptivity was tested according to the Matson method. The results showed that M. malabathricum’s flowers take 14 until 21 days from bud to flower bloom. Stigma M. malabathricum is already present and receptive before anthesis flower. Fruit can be formed through self pollination (autogamy) and cross pollination (xenogamy). M. malabathricum pollination approaches the xenogamy facultative.

The cultivated pear is an economically important fruit tree species of genusPyrusin 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.

Cytoplasmic male sterility (CMS) is maternally inherited trait; its phenotypic expression generally is due to interaction between sterile cytoplasm and recessive nuclear genes. Presently, commercial hybrid seed production of Capsicum relies on hand emasculation and pollination resulting in higher seed production cost to the seed producers. However, exploitation of CMS in hybrid seed production could significantly diminish its production cost and has capability to provide genetically pure seed. The best CMS approach is a 3-line hybridization method involving male sterile line (A-line), Maintainer line (B-line) and Restorer of fertility line (C-line). Availability and identification of Restorer of fertility ( Rf ) line in sweet pepper for suppressing male sterile phenotype in F 1 plants is difficult task. Thus identification of reproducible, co-dominant molecular markers linked to nuclear ( Rf ) and mitochondrial (S-cytoplasm) genes offers fast and reliable detection of parental lines during F 1 hybrid seed production. In this review, we tried to present the possibilities of exploiting CMS in Capsicum with their merits and drawbacks.

Background and Aims In animal-pollinated plants, direct and indirect selection for large and small flowers in predominantly outcrossing and selfing species, respectively, is a common consequence of pollen limitation (PL). However, many hermaphroditic species show a mixed-mating system known as delayed selfing, which provides reproductive assurance (RA) only when outcrossing is not realized. Although RA is expected to reduce pollinator-mediated selection towards larger flowers, the consequences of delayed selfing for selection on flower size in mixed-mating species remain overlooked. We investigated whether RA weakens selection on flower size in Tuberaria guttata, a mixed-mating annual herb. Methods We related pollinator visitation rates to flower size and measured seed production in emasculated, hand cross-pollinated and intact (control) flowers in three natural populations. For each population, we estimated variation in PL and RA across individuals differing in flower size and phenotypic selection on this trait. Key Results Pollinator visitation increased and RA decreased with flower size in all populations. Increasing RA diminished but did not fully alleviate PL, because of early-acting inbreeding depression. In the least-visited and most pollen-limited population, RA increased seed production by >200 %, intensely counteracting the strong pollinator-mediated selection for larger corollas. In the most-visited population, however, RA increased seed production by an average of only 9 %. This population exhibited the largest fraction of individuals that showed a decrease in seed production due to selfing and the weakest pollinator-mediated selection on flower size. Conclusions The results suggest that the balance between the extent of RA and outcrossing contributes to determine flower size in mixed-mating systems. Pollinator-mediated selection favours larger flowers by increasing outcrossed seeds, but the benefits of RA greatly lessen this effect, especially under severe conditions of pollen limitation. Our findings also indicate that a mixed-mating system can represent an ‘evolutionary trap’ under an adequate pollinator supply. Fil: López Teixido, Alberto. Universidad Rey Juan Carlos; España Fil: Aizen, Marcelo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

We studied the cross-compatibility among 91 inter-specific combinations and 21 inter-generic combinations in 7 Eriobotrya plants and 2 related genera (Raphiolepis indica Lindl. and Photinia serrulata Lindl.) using emasculation, bagging, and artificial pollination. Our results showed that 28 of the 91 inter-specific combinations set no fruit, which means nearly 30% of the combinations were incompatible. In the remaining 63 combinations, most showed partial cross-compatibility, and a few showed complete cross compatibility. Eriobotrya plants were incompatible with plants from their related genera (R. indica Lindl. and P. serrulata Lindl.). Backcrossing produced 5 compatible combinations, which could set fruits and produce F1 progeny but only after embryo rescue. Fruit setting ratios varied among various species used as male or female parents. E. prinoides Rehd. & Wils., common loquat (E. japonica) and Eriobotrya × daduheensis, used as female parents resulted in an average fruit-setting ratio of 36.2%–58.2%. E. deflexa Nakai and its two forms, and E. elliptica Lindl. as female parents resulted in 2.9%–16.3% average fruit-setting ratio; however, the fruit set ratio was higher (22.4%–43.1%) if they were used as male parents. Failure of E. deflexa f. koshunensis Nakai × E. prinoides Rehd. & Wils. hybrids to set fruit could be attributed to sporophytic incompatibility.

To explore the feasibility of intra specific hybridisation between Robinia pseudoacacia (common diploid) and other Robinia varieties, tetraploid R. pseudoacacia, R. pseudoacacia var. decaisneana (Carr.) Voss., R. pseudoacacia Frisia, and R. pseudoacacia “Idaho” were collected as male parents, and hybridisation trials were conducted over a period of three consecutive years. The average seedling emergence rates of the five hybridised combinations were ~2.3,2.0, 3.3, 1.3, and 0 % per year, respectively. To ensure maximum seedling emergence rates, we found that the best pollinating times were the blooming days. To investigate the causes of low crossability, we also examined pollen-tube growth and fruit setting rates. The results indicated that the causes of low crossability were abnormal pollen-tube growth, failed development of fertilised ovule, and poor seed germination. Low fruit-setting rates caused by emasculation may also lead to low crossability.

The resistant cultivar ?Panonia? and breeding lines from the species V. rotundifolia were cross bred and backcrossed to V. vinifera L. with the aim of creating new grapevine cultivars with good fruit quality and higher resistance to downy and powdery mildew. This way, resistance specificities from different genetic sources would be combined into cultivars with more robust resistance against a wider range of pathogen strains. A few seedlings with the highest level of downy and powdery mildew resistance were phenotypically selected after several years of field observations in unsprayed vineyards. The aim of this research was to determine the presence of known downy and powdery mildew resistance genes in the selected genotypes. Based on the pedigree, we assessed the inheritance of Rpv3, Rpv12, Run1/Rpv1, Ren3 which were present in the ancestors of these selections. Genomic DNA was extracted using a CTAB-based method from a young leaf. For PCR reaction we used published primers that generate polymorphic markers tightly linked to the genes. Two breeding lines tested positive for the presence of resistant alleles at all tested genes. One of them bears female flowers, it cannot be recommended for cultivation but it represents a convenient maternal parent for breeding - not requiring emasculation prior to blooming. The other is under evaluation for agronomic characteristics and wine quality. We provide further evidence of the strong predictive power of marker-assisted selection for Rpv3, Rpv12, Run1/Rpv1, Ren3.

High heterosis values can be obtained using hybrid okra seeds. However, despite high heterotic values, it is very difficult to produce hybrid okra seeds. The objective of this study was to evaluate an experimental methodology of hybridization. Two different methods of hybridization were used: traditional manual hybridization with complete emasculation followed by hand pollination (artificial) and, an experimental methodology, performing manual hybridization with incomplete emasculation followed by entomophilous natural pollination between two inbred lines (UFU-QB-040D and UFU-QB-107G).These inbred lines were obtained from three selection cycles. Three hybrid types were obtained from the two hybridization methods: F1 THM(UFU-QB-040D x UFU-QB-107G), F1 IHM(UFU-QB-107G x UFU-QB-040D) and F1 IHM(UFU-QB-040D x UFU-QB-107G). The resulting hybrid seeds and their parents were evaluated via an experiment set up in a randomized block design with four repetitions. We evaluated fruit production per plant, fruits per plant, number of branchess per plant, superiority of hybrids relative to parents (h) and heterosis (%). At the end of the cycle, morphological characterizations was done of the leaves (pubescence, length and width) and fruit (length, diameter and shape). Heterosis resulting from the incomplete emasculation followed by natural insect pollination was similar to that from the traditional hybrid method, being a viable alternative for the production of hybrid okra seeds without losses in heterosis. RESUMO Altos valores de heterose podem ser obtidos utilizando sementes híbridas de quiabo. Apesar dos altos valores heteróticos há grande dificuldade para produzir sementes híbridas de quiabo. O objetivo deste trabalho foi avaliar uma metodologia experimental de hibridação para produção de sementes híbridas de quiabo. Foram utilizadas duas metodologias de hibridação: hibridação tradicional, manual com emasculação completa seguida por polinização manual (artificial) e uma metodologia experimental, realizando hibridação manual com emasculação incompleta seguida por polinização entomófila natural, entre as duas linhagens endogâmicas (UFU-QB-040D e UFU-QB-107G). Essas linhagens endogâmicas foram obtidas após três ciclos de seleção. Utilizando as duas metodologias de hibridação foram obtidos três tipos de híbridos: F1 THM(UFU-QB-040D x UFU-QB-107G), F1 IHM(UFU-QB-107G x UFU-QB-040D) e F1 IHM(UFU-QB-040D x UFU-QB-107G). De posse das sementes dos híbridos e dos parentais foi realizado um experimento em delineamento em blocos casualizados com quatro repetições. Foram avaliadas a produção de frutos por planta, número de frutos por planta, número de hastes por planta, superioridade dos híbridos em relação aos pais (h) e heterose (%). No final do ciclo, foram realizadas a caracterização morfológico de folhas (pilosidade, comprimento e largura) e de frutos (comprimento, diâmetro e formato). Pode-se concluir que, utilizando a emasculação incompleta com polinização entomófila para produção de sementes híbridas de quiabo, foram obtidos valores similares de heterose quando comparado com a hibridação pelo método tradicional, indicando uma nova alternativa de produção de sementes híbridas de quiabo sem qualquer prejuízo no efeito heterótico dos híbridos.

Challenges in the emasculation of female parent panicles and limited morphological variation among canary seed (Phalaris canariensis L.) genotypes has resulted in a need for molecular markers to as...

Tagetes patula L. is an annual plant belonging to the Asteraceae family. Currently, commercial F1 cultivars are produced through the use of artificial emasculation which is a very laborious procedure, particularly in view of the composite capitulum structure. To date, no male sterile line is available in this species, but the isolation of such material would provide a valuable tool for the establishment of an efficient cross-pollination system for the production of F1 hybrids. In this study, we report the characterization of a novel pollen abortion mutant of Tagetes patula which was isolated from 1,796 heat shock induced cutting seedlings. Histological and cytological observation demonstrated that the abnormal development of the microspores during the binucleate pollen stage led to pollen abortion, and this was correlated to premature tapetum degeneration. Cross hybridization experiments indicated that a recessive nuclear gene was responsible for the trait. This novel male sterile mutant of Tagetes patula appears to be an applicable material for improving the breeding efficiency of the species and may be used to significantly improve ornamental traits in F1 generations.

The ‘Frangi’ papaya is a F1 hybrid developed by the Malaysian Agrifood Corporation Berhad (MAFC) from hybridization between 2 inbred parents ‘LSGC1’ and ‘LSGC2’. The seed production plot is located at Lanchang, Pahang which is about 100 km east of Kuala Lumpur. This so called ‘Lanchang Seed Garden’ occupies an area of 1 ha and in May 2007, 1800 trees of ‘LSGC1’ and 600 trees of ‘LSGC2’ inbred parents were planted. The trees flowered two months later and hybridization work was then started. Freshly dehisced anthers from ‘LSGC2’ (paternal parent) hermaphrodite flowers were collected in glass vials and used for pollination of ‘LSGC1’ (maternal parent) flowers. The recipient flower must be mature, but the corolla tube must remain folded to prevent accidental outcrossing. To effect pollination, the closed petals of the recipient female flower are gently separated to expose the stigma. One anther is picked up from the vial with a pair of curved-tipped forceps and gently rubbed onto the stigma of the ‘LSGC1’ flower. A wax paper envelope is then placed over the pollinated flower. Both female and hermaphrodite flowers of ‘LSGC1’ were used for hybridization and in the latter, emasculation by peeling off the corolla tube with its attached stamens is necessary to prevent self-pollination. Female flowers used in hybridization have the advantage of obviating emasculation and the fruit carries more seed compared with hermaphrodite, but its seed will bear a higher percentage of female trees that is not usually preferred. Reciprocal crosses using ‘LSGC2’ as maternal parent were also experimented with. ‘LSGC1’ as maternal parent produced fruit that was nearly twice the weight of ‘LSGC2’ and concomitantly the seed number per fruit was also doubled (245 vs. 121 seed). However, ‘LSGC2’ yielded 50% more fruit than ‘LSGC1’ and this accounted for a net 36% higher seed based on per tree basis. Over 18 months, ‘LSGC1’ and ‘LSGC2’ produced 15,042 and 20,510 seeds/tree, respectively. Field trials of F1 hybrids from direct and reciprocal crosses showed that there were no significant differences in performance. Hence, ‘Frangi’ seed production currently uses a 2-way cross. Seed harvest began in December, 2007 and rose to a peak of 90 kg in February, 2009. The trees after 18 months were too tall for hybridization and the seed garden was replanted after two years of seed production.

African yam bean (AYB) ( Sphenostylis stenocarpa (Hochst Ex. A. Rich) Harms is a neglected and underutilised legume in tropical Africa. Its utilisation has been hampered by the presence of anti-nutritional factors and lack of improved varieties. The objective of this study was to investigate pollination and determine the rates of selfing and outcrossing in the species. Accession TSs5 had the highest fruit set (63.16%) in the open-pollinated breeding method; while AYB50 had the lowest value (46.61%). Seed set in the selfed accessions ranged from 91.45% (AYB50) to 94.97% (TSs66). Fruit set was highest in the open-pollinated breeding method, with a mean average fruit set of 51.32%. Significant differences (P < 0.01) were obtained in fruit set from accessions isolated with net bags which had the lowest seed set (88.91%) Seed set was highest (92.92%) in the selfed accessions. The self incompatibility index ranged from 1.33 to 2.26 and the rate of fruit set from artificial self-pollination was greater than 30% in the field, and the screen house showing that the species is highly self compatible. Selfing and outcrossing rates of 91.38 and 8.62% showed that S. stenocarpa is not an obligate selfer. AYB sets fruits and seeds when open pollinated, isolated, selfed or crossed with other accessions. Key Words : Emasculation, self incompatibility, underutilised legume, Sphenostylis stenocarpa La legumineuse igname de l’Afrique (AYB) (Sphenostylis stenocarpa (Hochst Ex. A. Rich) Harms est une legumineuse negligee et sous utilisee en Afrique tropicale. Sa teneur en substances toxique et le manque de varietes ameliorees constituent un frein pour son utilisation massive. Il a ete ici question d’etudier sa pollinisation et de determiner les taux de pollinisation croisee et auto-pollinisation dans l’espece. L’accession TSs5 avait le nombre de gousses le plus eleve (63,16%) sous pollinisation ouverte, tandis que l’accession AYB50 a exhibe la valeur la plus faible (46,61%). Les nombres de gousses sous auto pollinisation variaient de 91,45% (AYB50) a 94,97% (TSs66). Ce nombre etait plus eleve sous pollinisation ouverte, avec une moyenne de 51,32%. Des differences significatives (P < 0.01) ont ete observees dans les nombres de gousses chez les accessions protegees par des filets et qui avaient les plus faibles nombres de grains (88,91%). Le nombre de grains le plus eleve (92,92%) etait observe par auto pollinisation. L’indice de d’auto incompatibilite etait de 1,33 a 2,26 et le taux de fructification chez les plantes artificiellement auto pollinisees etait superieur a 30% dans le champs, et en serre, indiquant ainsi que l’espece est hautement auto compatible. Les taux d’auto pollinisation 91,38 et de pollinisation croisee 8,62% montrent que l’auto pollinisation chez S. stenocarpa n’est pas obligatoire. AYB produit des gousses et graines sous toutes forms de pollinisation. Mots Cles : Emasculation, auto incompatibilite, legumineuse sous utilisee, phenostylis stenocarpa

The study of ovule senescence in the ovaries of four sweet cherry cultivars (‘Karina᾿, ‘Kordia᾿, ‘Regina᾿ and ‘Summit᾿) in the environmental conditions of West Serbia was carried out. Monitoring of ovaries was performed using the fluorescence microscopy method, on emasculated and pollinated flowers (cross-pollination variant), non-emasculated open-pollinated flowers (open pollination variant), and emasculated unpollinated flowers (unpollinated variant). In cross- and open pollination variants, the rate of unusual pollen tube growth in the ovary, fertilization percentage and fruit set were determined. The tendency in the appearance of fluorescence, as an indicator of ovule senescence, showed strong genotypic dependence ‒ it was the most and the least pronounced in the ovaries of ‘Kordia’ and ‘Regina’, respectively, in all the flower categories. Investigation of unusual pollen tube growth, fertilization percentage and fruit set, considered from the aspect of ovule senescence and cultivars’ behaviour as female (pollinated), pointed to their specific relations and complex dependence on the air temperature before and during the flowering. Flower emasculation and pollination also influenced ovule senescence, and this impact was unequal by genotypes, i.e. those having better ovule vitality in general, had also better ovule vitality in the conditions of emasculation, and pollination absence. The results imply different adaptation of cultivars to higher temperatures before and during the flowering, pointing to the further investigation related to the good adaptability of genotypes to air temperatures in reproductive sense, which is a basic indicator of good adaptability in general.

Aims The stamens of Glycyrrhiza species are diadelphous, with nine staminal filaments united at the base as a staminal sheath and separated in the upper portion of the staminal sheath. The arrayal shape of the nine stamens changes from two rows at an early stage to an inverted "V"-shaped arrangement at a later stage. Our objectives were to (1) describe development of the stamens in G. glabra (from the bud stage to full bloom) to determine dif- ferences in shape development, timing and position of stamens and (2) determine the functional role of long- and short-level stamens in the pollination processes and its adaptive significance. Methods The development of stamens (measurement of the filament, anther, and style lengths at five develop- mental stages) and variability of timing and position of stamens were observed under a dissecting microscope. Scanning electron microscopy recorded pollen morphology. The vitality, quantity and chemical composition of pollen were counted and detected. In addition, the number of seeds following each pollination treatment and the pollinator behavior of insects on different stamen removal treatments were compared to examine differentiation of long- and short-level stamens. Important findings There were differences between the long- and short-level stamens in filament length, anther size and shape early in development, but the differences disappeared when filaments elongated and mature pollen was released. The numbers of pollen grains and pollen vitality between the long- and short-level stamens were different later in development. However, no significant differences were observed in chemical composition of pollen and seed sets among different treatments. Emasculation of the long- and short-level stamens induced reduc- tions in the visiting frequency, but the seed sets of emasculation were higher than without emasculation, which indicates that emasculation reduces the interference between stamens and stigma and improves the pollination rate. The arrayal shape of stamens changed from two rows early in time to an inverted "V"-shaped arrangement at a later stage and resulted in different quantity and vitality of pollen. This indicates that the flower of G. glabra

The effect of the pollination time and of the pollen origin was studied in three self-compatible and late-blooming almond genotypes in order to evaluate their effect on fruit set and yield. The full self-compatibility of the three genotypes was clearly assessed as fruit sets after self-pollination were similar to those obtained after cross-pollination with pollen from two different genotypes. Sets reached the level of a commercial production, ranging from 34.02% to 49.98% when the flowers were pollinated at the best pollination time, two days after emasculation. Pollination at later times significantly decreased fruit set, as well as high temperatures, negatively affecting stigma receptivity and, consequently, pollen germination and fruit set. Thus, early pollination is essential for self-compatible almond cultivars, mainly if these cultivars are grown in regions with warm conditions in late winter and early spring.

A berinjela é uma espécie autógama, de flores perfeitas e que ainda não dispõe de sistema genético de macho-esterilidade para uso em escala comercial. Assim, a tecnologia de produção de sementes híbridas envolve emasculação e polinização manuais. No presente trabalho avaliou-se a produção e a qualidade de sementes híbridas de berinjela oriundas de plantas com diferentes números de frutos por planta, fecundados artificialmente. O experimento foi conduzido em campo de produção de sementes híbridas de berinjela 'Ciça' na Embrapa Hortaliças e os tratamentos corresponderam a diferentes números de frutos fecundados mantidos por planta (6, 9, 12, 15 e 18). Foram selecionadas seis plantas/repetições para cada tratamento, nas quais os botões florais foram emasculados manualmente e realizados cruzamentos controlados. Foram avaliados 1) número de sementes por fruto; 2) número de sementes por planta; 3) massa de sementes por planta; 4) massa de 100 sementes; 5) teste padrão de germinação; 6) primeira contagem; 7) classificação do vigor; 8) envelhecimento acelerado; 9) teste de frio e 10) emergência de plântulas. O maior número de sementes por fruto foi obtido em plantas com seis frutos e o menor em plantas com 15 e 18 frutos. Plantas com 12, 15 e 18 frutos apresentaram maior número e massa de sementes por planta. Os tratamentos não diferiram quanto à massa de sementes, primeira contagem, germinação e plântulas normais. O teste de envelhecimento acelerado indicou que o período de 72 h se relaciona melhor com a germinação. O estabelecimento do limite de 12 frutos por planta está próximo do ideal, uma vez que permite a racionalização da mão-de-obra quanto ao número de interferências realizadas pelo produtor de sementes híbridas. Eggplant is an autogamous species (perfect flowers) and with no genetic male-sterility system yet available for commercial use. Therefore, the technology of hybrid seed production is based upon hand emasculation and pollination. The present study aimed to evaluate if the yield and quality of hybrid seeds of eggplant is affected by the number of fruits kept in the plants after controlled pollination. Plants were selected within a production field of hybrid seeds of eggplant 'Ciça' and controlled crosses were performed. The treatments (six plants each) consisted of keeping 6, 9, 12, 15 and 18 fruits per plant after controlled hand emasculation and pollination of the flower buds. The following tests and determinations were performed 1) number of seeds per fruit; 2) number of seeds per plant; 3) seed weight per plant; 4) weight of 100 seeds; 5) germination; 6) first count; 7) vigor classification; 8) accelerated aging; 9) cold test and, 10) seedling emergence. The greatest number of seeds per fruit was obtained in plants with six fruits, and the lowest average in plants with 15 and 18 fruits. Seed production and seed weight per plant displayed similar results for all treatments. Plants with 12, 15 and 18 fruits showed higher weight and number of seeds per plant. No statistical differences were observed for the treatments: seed weight, first count, germination and normal seedlings. In the accelerated aging test results indicated that the period of 72 h was more related to the germination test. It is suggested that using 12 fruits per plant would be the most efficient technology in terms of labor force management (hand emasculation and pollination).

Breeding in Ziziphus mauritiana Lam. through hybridization is limited by its small sized flowers, cross-incompatibility, low fruit-set and poor retention. In the present study, emasculation of flowers 2 h before anthesis and pollination by placement of dehisced flowers on stigma in inverted position resulted in increased fruit-set. Crossing of Z. mauritiana cultivars Gola and Thar Sevika (early maturity and fruit quality) with cultivars BS-1 (powdery mildew resistant) and Tikadi (fruit fly and frost tolerant) showed that Thar Sevika is cross compatible with BS-1 and Tikadi whereas Gola is cross compatible with BS-1 only. Among the crosses fruit-set range was 2.31–10.92%. Based on the presence of male parent-specific DNA fragment produced by RAPD and ISSR markers 13 out of 14 F1 progeny seedlings were found to be true hybrids. This is the first report in Z. mauritiana on the identification of true hybrids among F1 progenies using molecular markers.

The aim of the apricot-breeding program in the Horticultural Faculty in Lednice, that has been developed since 1981, is to obtain new adaptable cultivars, which combine most of the valuable biological traits. Standard breeding techniques, such as crossing by emasculation and hand pollination, self-pollination and open pollination, were employed. A total of 1.154 crossings were produced from more than 110 different parents. So far more than 20,000 seedlings have been obtained, of which about 13,000 have already been evaluated. The most interesting selections were grafted and planted in trial orchards (we now have more than 650 elite genotypes). Ten of these have already been registered, and further promising new hybrids have been submitted for registration and law right protection (Betinka, Candela, Sophia and Adriana). The basic prerequisite for the initiation of the breeding program was a large collection of genetic resources, established and gradually supplemented since the 1970s. At the present time, we preserve and manage more than 300 accessions of apricot trees. In the frame of the descriptive work of the genetic resources and in order to use in breeding, a collection of apricots has been evaluated. We selected the genotypes and characters relating to an increased level of adaptation to the environment. info:eu-repo/semantics/openAccess

Parthenocarpy—the production of seedless fruits without fertilization—is very useful for fruit cultivation, especially in self-incompatible species such as pears. To search for parthenocarpic genetic resources in pear, 31 pear accessions [20 Chinese pears (13 Pyrus bretschneideri, seven Pyrus ussuriensis), five European pears (Pyrus communis), two Japanese pears (Pyrus pyrifolia), and four interspecific hybrids] were subjected to flower emasculation and left unpollinated, and then the fruit-set ratio and fruit enlargement were investigated. All European pears examined had a stable and high degree of fruit set, and ‘La France’ had high fruit enlargement. The possibility of stenospermocarpy was ruled out, because the emasculated flowers were left unpollinated in paper bags and the absence of seed was confirmed in the enlarged fruits. Neither Chinese nor Japanese pears treated with emasculation and no pollination showed consistently stable fruit set and fruit enlargement. An analysis of parthenocarpy in the offspring of ‘La France’ suggested that both high fruit set and fruit enlargement were inherited and that it should be possible to introduce parthenocarpy into Japanese pears. Although parthenocarpic ‘La France’ fruits weighed slightly less than those from cross-pollinated flowers, their cortex enlargement compared favorably with that seen with cross-pollinated ones. By using a customized pear cDNA microarray, we compared the gene expression profiles of highly and weakly parthenocarpic cultivars before flowering. Expression of several phenylpropanoid-related genes and photosystem-related genes differed significantly between the two groups. Some of these genes were putatively encoded in the chloroplast genome. These genes might be candidates of DNA markers for achievement of parthenocarpy in Japanese pear breeding.

Although self-compatibility is a genetically qualitative trait in almond, its expression has been shown to be variable and dependent on the genotype. Thus, pollen germination and pollen tube growth were studied in the progenies of two different crosses, involving the same self-compatible female parent, ‘Mardia’ (S6Sf), and two self-incompatible male parents ,‘Desmayo Largueta’ (S1S10) and ‘Marcona’ (S11S12). Pollen germination was tested following the Hermosa procedure and pollen tube growth was assessed in the lab after hand self-pollination of pistils following flower emasculation, pistil sampling after 96 hr and pollen tube growth observation by microscopic observation with fluorescence light. The results were statistically evaluated by variance analysis and the means were compared by the Duncan Multiple Range Test (DMRT). Results showed that pollen germination in an artificial medium was good for all progenies, with no significant differences between the individuals. Pollen tube growth, however, showed significant differences (5% level) between the styles of self compatible and self-incompatible seedlings. The observation of pollen tube growth after self-pollination allows not only the differentiation of the self-compatible plants and the determination of the phenotype frequencies, but also the establishment of the quality of the self-compatibility expression and the possible interest of each plant of the breeding program.

For the first time, reciprocal intergeneric hybridizations were produced between Opisthopappus taihangensis and Chrysanthemum lavandulifolium without emasculation. About 20% seed set was similarly obtained from reciprocal hybridization. Only 5 and 6 of the viable plants observed from 45 and 78 seedling survived present some conspicuous intermediate characteristics. Phenotypic evaluation among the progenies of the parents and the putative hybrids was performed carefully since an average of 5.3% seed set was produced in the type of self-pollination using pollen from the same flower and >10% seed set was similarly obtained in the types of self-pollination using pollen from different flowers in a plant and flowers in individual plants from different seeds. One individual of each hybrid shared the inflorescence habit with the pollen plant was confirmed further by the sequence of ncpGS. The two hybrids might be used as bridges of breeding of multi-generic hybrids.

To determine the viability of hot water emasculation for Acacia auriculiformis, spikes composed of about 100 flowers were soaked in hot water at varying temperatures (45–60°C) and for varying lengths of time (5 s to 7 min) prior to anthesis. The rate of squashed polyads, each of which consisted of 16 pollen grains, and the germinating rate on media, decreased with temperature and time. A mating test suggested that the rates of adhering polyads per stigma and germinating polyads per stigma were lower in the self-pollination of soaked spikes than in that of normal spikes. On the other hand, the number of matured pods was not significantly different in the mating between the spikes receiving the soaking treatment (♀) and the spikes receiving no treatment (♂) compared with the mating between normal spikes. Although further research is needed to determine the optimal treatment conditions, these results suggest that soaking spikes into hot water, especially at 50°C for 45 s, 54°C for 15 s, and 56°C for 10 s, is an effective emasculation technique.

Italy is the third greatest producer country in the world, with over 7% of global apricot production. Apricot is grown in many Italian regions, but the Vesuvian area, in Campania region, is the most traditional area of cultivation. In this area, the apricot biodiversity is rather ample: roughly 30 different varieties are normally cultivated, while more than one hundred have been recognized. This biodiversity has also been employed in a genetic improvement programme of apricot to meet the needs and the applications of growers and the processing industry. The programme was started with the aim of reaching the following main goals: early and late ripening, elevated and regular productivity, high quality of fruit (size, sugar content, aroma, flesh firmness, etc.), resistance to the most important diseases (Monilinia laxa, Sharka) and processing suitability. Standard breeding techniques, i.e. self pollination, open pollination, crossing by emasculation and hand pollination have been employed. In this programme, 84 varieties of apricot, coming from different geographical areas, have been used, thus realizing 156 different combinations that have produced over 7000 seedlings, of which more than 4000 have already been considered. Two new early ripening cultivars, Ischia and Procida, were patented in 2007, but many others are interesting selections that will be proposed to the growers. These selections, still being valued, could allow extending and completing the ripening calendar; some others possess interesting characteristics. As for the growth habits, different typologies have been observed - spur, weeping, flattened - which can be also of some interest for the realization of particular forms of training. Tests are in progress in order to determine the agronomic behaviour of these selections in different environment of Southern Italy.

Rice productivity can be enhanced through exploitation of heterosis in hybrids with a possible positive impact on food security. Making planned crosses is difficult in rice because of the morphology and size of the inflorescence. This study was undertaken to investigate the efficacy of a gametocide (ethrel) as an emasculating agent. Experiments were conducted at ICRISAT Research Station at Samanko in Mali during 2004–2005. A factorial arrangement in a randomized complete-block design involving three levels of concentrations of the gametocide and five application stages was undertaken for two seasons. Morpho-physiological trait responses and spikelet sterility data were recorded on the female treated plants. Ethrel could induce 40 to 49% male sterility in rice. Percentage of empty spikelets and male sterility increased with increasing concentration of ethrel, reaching a peak between 2,000 ppm (2.0 g L−1) and 4,000 ppm (4.0 g L−1). Male sterility induction of 41.5% and 42.8% at 2000 ppm was achieved in 2004...

Acacia mangium is a major plantation species for the pulp and paper industry in south-east Asia and there are a number of active breeding programs. The species is predominantly outcrossing, but with a demonstrated capacity to set selfed seed where outcross pollen is limited, with consequent inbreeding depression in the progeny. Current controlled pollination methods therefore include a time-consuming emasculation step. We used microsatellite genotyping of seedlings to determine the consequences of outcross pollination with and without emasculation. Only 1 of 3 mother trees set a small amount (5%) of selfed seed. Using whole inflorescences from the male parent as the pollen applicator rather than sieved pollen reduced outcross contamination rates from 19.1 to 8.7% and substantially increased worker productivity. Application of sugar solution to the female flowers immediately prior to pollination increased yield of sound seeds per spike. Additional improvements to the pollination protocols are discussed.

Controlled pollination (CP) is a labour-intensive, but useful procedure applied in tree improvement programmes. However, the high costs involved and relatively low seed yields often obtained has, in most cases, necessitated the use of lower quality, open pollinated seed. The aim of the present study was to compare control-pollination methods for combinations among small-flowered eucalypt species. By making crosses within and among Eucalyptus grandis, E. smithii and E. macarthurii, we compared effectiveness, in terms of seed production and level of genetic contamination, of three CP techniques, namely emasculation of bagged flowers and subsequent pollination of receptive stigmas (Conventional method), emasculation and immediate pollination of stigmas with induced receptivity followed by bagging (One Stop Pollination), and pollination of cut styles without emasculation and bagging (Artificially Induced Protogyny). One tree of each species was used as the female in these crosses. Although Artificially Induced Protogyny using ripe and semi-ripe buds produced the highest seeds/flower pollinated in the majority of crosses carried out in this study, the technique, when performed on green buds, resulted in the highest capsule abortion. Molecular analysis using microsatellite markers also revealed that progeny from the Artificially Induced Protogyny method, when using green and semi-ripe buds, were highly contaminated by self- and external pollen. Of the three CP-techniques tested, One Stop Pollination had the lowest genetic contamination. However, this technique also had one of the lowest seed yields, while the Conventional method was intermediate in performance.

Twelve genetically diverse and geographically distinct high erucic acid rapeseed (HEAR) Brassica napus L. cultivars/lines were selected and crossed by hand emasculation in a topcross design to produce 45 F1 hybrid combinations. Seven of the twelve parents were HEAR cultivars/lines developed by the University of Manitoba (UM) and the remaining five parents were proprietary European (EU) HEAR cultivars/lines. Adequate seed was produced to evaluate the hybrids and parents in replicated yield trials in six environments in Manitoba during 2004 and 2005. Vigor, days to first flower, days to maturity, lodging, plant height, and seed yield were assessed. The hybrids were generally more vigorous, taller and more lodging resistant than their parents with similar days to first flower and days to maturity as their earlier parents. The best hybrids in this study displayed high parent heterosis for seed yield of up to 143% and commercial heterosis for seed yield of up to 99%. These hybrids were from the most genetically diverse UM × EU crosses. HEAR hybrids appear very promising approach to increase seed yields in this crop. Key words: Brassica napus L., HEAR, heterosis, hybrids, genetic diversity

SummaryThe effective pollination period (EPP) was determined over 2 years for ‘Guara’, an autogamous almond [Prunus amygdalus Batsch syn. P. dulcis (Mill.) D.A. Webb] cultivar, in order to understand the influence of pollination time on its irregular fruit set. Stigma receptivity, pollen retention, and pollen-tube growth were assessed after self-pollination at different time-intervals following bud emasculation. In general, fruit set, the percentage of pistils with pollen grains and with pollen tubes at the style base, and the mean number of pollen tubes, had maximum values on day-2 after emasculation, which corresponded to anthesis. Warmer temperatures during the study in 2006 probably reduced fruit set.These results emphasise the importance of early pollination of flowers, as well as adaptation to higher temperatures during bloom in an autogamous almond cultivar.

The objective of this study was to evaluate the effect of different artificial cross pollination techniques in cubiu (Solanum sessiliflorum) for breeding purposes and genetic control studies of economically important traits. The varieties Santa Luzia and Thais, with and without protection with organza cloth, were used in natural crosses and crosses with emasculation. The methods were evaluated for pollination efficiency and fruit traits, namely: weight, length, width, length/ width ratio and mean number of seeds. RAPD analysis indicated that all progenies were derived from the controlled crosses, which confirmed the pollination efficiency of the methods applied. The pollination efficiency varied from 4.57% to 8.37% among the crosses. The use of emasculation without organza cover was statistically best for fruit yield. The variety Santa Luzia is recommended as female parent for hybridization. Crossing seems to be the predominant mechanism of reproduction in this species.

Pod production and hybrid seed yield were observed in breeding garden of Acacia mangium x Acacia auriculiformis . The breeding garden was established in 2006 using 6 selected plus trees from first-generation progeny test of A. mangium and 12 selected plus trees from first-generation progeny test of A. auriculiformis . Based on synchronisation in first phase flowering time (one year of age), there were 6 crossing combinations between A. mangium x A. auriculiformis . Twenty three (23) crosses were done with A. mangium as mother tree. Crosses were practiced by using about 2 spikes for each cross. In the first phase of flowering time, pod production and hybrid seed yield was still low with about 1.87 pod per spike and 2.05 good seeds per pod. This low production is probably due to the low intensity of flowering and lack of male flower in this first phase flowering. In addition, high incompatibility between pistil and pollen among the two different species also affected quality of seed in which about 1.54 seed per pod or 28,75% are poor hybrid seeds. Verification using seedling morphology indicated that almost all collected seed were hybrid seed. This finding showed that anther method without emasculation seemed to be effective to produce hybrid seed of A. mangium x A. auricuiliformis .

The objective of the research was to assess a grade of parthenocarpic fruit and fruitsetting following cross-pollination and self-pollination in pepino plants (Solanum muricatum Ait.). An experiment with six pepino clones of different origin was set up in glasshouse conditions. Experimental clones were subjected to the following treatments: self-pollination, cross-pollination, and emasculation without any control. The tested clones of pepino were self-pollinated, capable of cross pollination and facultative parthenocarpic. The differences between clones in their ability to parthenocarpic fruit formation were observed. The ripening period of pepino fruits and their weight depended on a clone.

In animal-pollinated plants, autonomous selfi ng provides reproductive assurance under conditions of infrequent pollinator visits or a lack of mates, but few data are available for wind-pollinated species or species with combined insect and wind-pollination, for which it is often assumed that pollen availability does not limit reproduction. In this study, the capacity of autonomous selfi ng was investigated in the temperate forest herb Paris quadrifolia , and an emasculation experiment was performed under natural fi eld conditions to investigate the contribution of autonomous selfi ng to total seed set across a continuous gradient of densities of fl ering conspecifi cs. In the absence of wind or pollinators, autonomous selfi ng was observed through anthers approaching stigmas at the end of fland the capacity for autonomous pollination was about 0.34. Under natural conditions, considerable out- cross pollination was observed, but the proportion of ovules successfully fertilized signifi cantly decreased with decreasing density of conspecifi cs when fl owers were emasculated, but not when fl owers were left intact. These results indicate that autonomous self- ing resulted in reproductive assurance (RA = 0.16) and thus support the hypothesis that autonomous selfi ng can also provide reproductive assurance in wind-pollinated species.