Pollinizer Cultivars Research Articles

APPLYING GENETIC MARKERS FOR SELF-COMPATIBILITY IN THE WSU SWEET CHERRY BREEDING PROGRAM

Sweet cherry (Prunus avium) is a member of the Rosaceae family, with a gametophytic self-incompatibility system that strongly affects pollination and fruit set. Alleles at the S-locus control this system, and fertilization does not occur if the S-allele of a haploid pollen gamete matches either S-allele of the diploid maternal pistil. To produce fruit, self-incompatible cherry trees require nearby cross-compatible trees with synchronous flowering. In cherry orchards, two or more cross-compatible pollinizer cultivars are therefore usually inter-planted with the main cultivar. Fortunately, self-compatibility exists, the result of a mutation of one of the alleles at the S-locus, permitting the breeding of self-compatible cultivars that do not require pollinizer trees. The Washington State University (WSU) sweet cherry breeding program seeks to produce self-compatible cultivars (in addition to superior fruit quality and other trait improvements) and desires an early detection system for self-compatible seedlings. PCR-based S-genotyping that included primers for detecting self-compatibility was conducted for 243 seedlings from crosses made in 2004 that initiated this modern breeding program. While self-compatible seedlings were identified, a large proportion of seedlings resulted from unintended parentage, with implications for future breeding strategies.

Investigation of the fertilization biology of some sweet cherry cultivars grown in the Central Northern Anatolian Region of Turkey

The experiments were carried out between 2003 and 2005 in the Province of Amasya. The first objective of the study was to determine the best pollinizer for the cultivar ‘0900 Ziraat’ which is the most popular sweet cherry cultivar ( Prunus avium L.) in Turkey. The ‘0900 Ziraat’ was used as a female parent and ‘Türkoğlu’, ‘Köroğlu’, ‘Kargayüreği’, ‘Hacı Ali’, ‘Starks Gold’ and ‘Geçkiraz’ were used as pollinizer cultivars. In 2003, for the hand cross pollination combinations, fruit set was between 31.25% and 42.80%. In 2004, fruit set was reduced by spring frost and was between 9.69% and 15.24%. Additionally, the blooming periods of the experimental cultivars, fruit set of open pollination and hand self pollination were examined. The fruit set ratios of all tested cultivars under open pollination conditions varied between 26.73% and 53.49% in 2003 and 4.38% and 38.35% in 2004. ‘Geçkiraz’ had the highest fruit set owing to its late flowering date. For open pollination, fruit set values of ‘0900 Ziraat’ were lower than hand cross pollination with other cultivars in 2003 when the results of both treatments are compared. On the contrary, fruit set was higher than hand cross pollination in 2004. In the present study, pollen germination values varied greatly among year, cultivar and sucrose concentration. Viability percentages were generally high, not less than 66%. According to phenological observations, partial or complete overlapping of the flowering period of ‘0900 Ziraat’ and its possible pollinizer cultivars were observed in 2003 and 2005. But in 2004, the flowering period overlapped for only ‘0900 Ziraat’ and ‘Geçkiraz’ cultivars. When blooming times are taken into consideration, ‘Geçkiraz’ was found to be the best pollinizer cultivar.

Genomic characterization of self-incompatibility ribonucleases (S-RNases) in loquat (Eriobotrya japonica Lindl.) (Rosaceae, Pyrinae)

Loquat (Eriobotrya japonica Lindl.) is a fruit tree species of the Pyrinae subtribe of the Rosaceae that behaves as self incompatible. Since self-incompatibility in the Rosaceae is of the gametophytic type where a stylar ribonuclease (S-RNase) controls the female function of pollen–pistil recognition, consensus primers derived from the alignment of S-RNase sequences from other Pyrinae species were used to search for S-RNases in loquat. As a result, the first four S-RNases were sequenced for this species. The genomic sequences obtained showed the structural features of Pyrinae S-RNases. Moreover, microscopic observations of pollen tube growth in the style confirmed the inter-(in)compatibility relationships predicted from the molecular analyses. Phylogenetic analysis of the deduced amino acid sequences with other Pyrinae S-RNases confirmed that divergence of S-alleles in loquat and the Pyrinae predated speciation. This study reports for the first time the genomic characterization of S-RNases in loquat, providing a sound basis for an appropriate selection of pollinator cultivars and an adequate design of breeding programs.

Fenologia de espécies silvestres de macieira como polinizadora das cultivares gala e fuji

A escolha correta de cultivares polinizadoras na macieira é determinante para a obtenção de altos rendimentos. Muitas regiões produtoras de maçãs do mundo utilizam macieiras silvestres com o fim específico de polinização, porém existem poucas informações quanto ao uso dessas espécies nas condições climáticas do Sul do Brasil. O objetivo deste trabalho foi avaliar o comportamento fenológico de espécies silvestres de macieira quanto à floração em comparação as cultivares comerciais 'Gala' e 'Fuji', nas condições climáticas do Sul do Brasil, em Caçador-SC (latitude 26º42'32" sul, longitude 51º00'50" oeste e altitude de 960 metros). As macieiras silvestres estudadas foram M. atrosanguinea, M. baccata, M. eleyi, M. floribunda, M. hopa, M. platycarpa, M. robusta, 'John Downil', 'Prof. Spengler', 'Milalew imuni', 'Profusion', 'Winter gold' e 'Yellow Siberian'. As espécies silvestres apresentaram grande variabilidade na época de florescimento e na duração do mesmo ao longo dos anos. A maior coincidência do período de floração e com maior regularidade ao longo dos anos foi obtido entre às cultivares Gala e Fuji. 'Prof. Spengler', 'Profusion', 'Winter gold' e 'John Downil' são as espécies silvestres de macieira com maior potencial de utilização como polinizadoras, podendo ser utilizadas complementarmente para polinização das cultivares Gala e Fuji. As espécies M. hopa, M. eleyi e M. atrosanguinea, devido à alta densidade de floração, podem ser utilizadas como segunda opção para a polinização das cultivares Gala e Fuji.

Identification of S-genotypes and novel S-RNase alleles in Prunus mume

SummaryPrunus mume (Japanese apricot) cultivars are self-incompatible and orchards require pollinator cultivars to guarantee optimal fruit production. Identification of the self-incompatibility (S) genotypes of P. mume cultivars is therefore useful for choosing pollinators and for breeding. To elucidate the S-genotypes of eleven Chinese and one introduced cultivar, PCR was performed with primers amplifying the variable second intron of the S-RNase gene. The S-genotyping results were as follows: S4S12 for ‘Dantaofen’; S3S4 for ‘Duoezhusha’; S12S13 for ‘Fubantiaozhi’; S15S16 for ‘Hongding’; S13S14 for ‘Longyanmei’; S5S11 for ‘Musashino’; S10S14 for ‘Xiaoyezhugan’; and S3S15 for ‘Qingfeng’,‘Qingjia’, ‘Xiyeqing’, ‘Dayeqing’ and ‘Changnong 17’. We identified seven new S-RNase alleles, S10-RNase to S16-RNase, deposited in GenBank under the accession numbers: DQ011150, DQ201191, DQ201192, DQ345781, DQ768219, DQ903312 and EF990750, respectively.

EFFECT OF INCREASING THE DISSOLVED OXYGEN IN THE NUTRIENT SOLUTION TO ABOVE-SATURATION LEVELS IN A GREENHOUSE WATERMELON CROP GROWN IN PERLITE BAGS IN A MEDITERRANEAN AREA

EFFECT OF INCREASING THE DISSOLVED OXYGEN IN THE NUTRIENT SOLUTION TO ABOVE-SATURATION LEVELS IN A GREENHOUSE WATERMELON CROP GROWN IN PERLITE BAGS IN A MEDITERRANEAN AREA

Determination of (in)compatibility genotypes of Hungarian sweet cherry (Prunus avium L.) accessions by PCR based methods

Sweet cherries (Prunus avium L.) are generally self-incompatible and pollinator cultivars are needed in orchards for reliable yield. In Hungary, choosing the appropriate cross-compatible cultivar pairs has so far been based on traditional test-crosses in the field. In recent years PCR-based methods that allow the identification of the S-alleles responsible for compatibility have been elaborated. We have determined the S-allele constitution of 24 cultivars and four selections important to Hungarian growers and breeders using PCR-based methods developed at Horticulture Research International, East Malling. The 28 accessions had various pairs of 9 alleles including one new allele, Sr. They could be assigned to 12 of the existing incompatibility groups or to a new group (S4S12) for which the designation 'Group XXVII' is proposed. The cultivars `Krupnoplodnaja' and 'Rita' had novel genotypes, S5S9 and S5Sx, respectively and can be placed into group 0 that holds universal pollen donors. The genotype of the cultivar ‘Hedelfingeni óriás' grown in Hungary was found to be S3S4 and therefore different from the cultivar `Hedelfingen' that is widespread in Western Europe.

Pollination Biology of the Muscadine Grape

Fruit set in the muscadine grape (Vitis rotundifolia Michx.) depended on insect cross-pollination, although flowers were well adapted for selfing. Pollinizer cultivars produced about half of their optimal fruit set when selfed, but cross-pollination was needed to reach an optimal fruit set of 33.7%. Eighty-one percent of the overall fruit set in pistillate vines was attributed to insect cross-pollination; wind played only a small role. Diminished fruit set and fewer seeds per berry occurred in cultivars receiving no effective cross-pollination. Components of fruit quality were not profoundly affected by the pollination treatments, although seed set and berry weight in pistillate cultivars was lower in the absence of cross-pollination. Parthenocarpy was rare, except in `Fry Seedless'. Muscadine production throughout the southeastern United States depends on cross-pollination by indigenous insects, particularly bees. To ensure consistently high yields, bees must have safe access to flowers and their nesting sites must be preserved.

Across- and along-row pollen dispersal in high-density apple orchards: Insights from allozyme markers

SummaryThe organization of most high-density orchards of apple (Malus x domestica Borkh.) into single-cultivar rows is often viewed as an impediment to effective pollen dispersal and pollination; however, few direct estimates of pollen dispersal are available to assess the extent of this problem. We estimated the magnitude of pollen dispersal across rows (pollinator cultivars: Idared, Vista Bella, Granny Smith), and along rows, (pollinator cultivars Fuji, Paulared, Golden Russet), in two high-density orchards in Ontario, Canada. Fruit were sampled from trees at regular intervals along transects that extended beyond (either across or along row) each pollinator cultivar and the percentage of seeds that were sired by the pollen donor was estimated using allozyme markers. Seeds sired by the pollinator cultivar were found from seven (‘Granny Smith’) to 18 rows (‘Idared’) from the nearest pollinator tree and from seven (‘Fuji’, ‘Paulared’) to five trees (‘Granny Smith’) down the same row. Measured in metres, the maximum pollen dispersal distance was greater across rows (62.4.m) than along rows (13.7.m). However, the average dispersal distance across rows, expressed in metres or trees, (17.4.±m.3.6, 3.6.±0.7 trees) did not differ from that along rows (5.8.m.±4.1, 2.7.±0.8 trees). These results are at odds with previous studies that indicate that honeybees move farther along rows than across, and have important implications for the design of commercial apple orchards.

Hazelnut Pollination

Hazelnuts, (Corylus avellana L.), are wind-pollinated, monoecious, mostly dichogamous, and self-incompatible. About 90% of the cultivars studied are protandrous. Anthesis of the pistillate flower is temperature-dependent and occurs December through February, peaking in January. Stigmatic surfaces may remain receptive for up to 3 months. Four to 5 months separate pollination and fertilization of the ovule; the latter usually occurring between mid-May and the end of June in Oregon. A 10% pollinizer density has been the standard, with a recommended distance of 66 ft (20 m) or less between the main cultivar and the nearest pollinizer. Two or three different pollinizer cultivars, with different times of pollen shed, are recommended. The Oregon hazelnut industry is presently combating the fungal disease, eastern filbert blight, caused by Anisogramma anomala (Peck). Current management recommendations suggest reducing risk of infection are to reduce the most susceptible pollinizer cultivars to a density 5%, then gradually replace those left with immune or more resistant genotypes.

First Report of Leaf Spot Caused by Alternaria alternata on Kiwifruit in Italy.

A leaf spot of kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang & A. R. Ferg.) leaves was recently observed on plants of the cultivar Hayward in an orchard near Salerno, in southern Italy. The affected plants showed early severe defoliation. The fungus isolated from the infected leaves was identified as Alternaria alternata (Fr.:Fr.) Keissl., based on conidial morphological characteristics. Pathogenicity tests were made by inoculating detached leaves of male pollinator cultivar Tomuri and the female cultivars Hayward and Bruno with a 7-mm disk taken from actively growing cultures of the fungus on potato dextrose agar (PDA). After 14 days, necrotic leaf spots developed and A. alternata was consistently isolated from the inoculated leaves. A. alternata has been observed as a pathogen on leaves and fruits in New Zealand. In the Mediterranean, it has been reported in Israel (2) and in the island of Crete (1). This is the first report of Alternaria leaf spot on kiwifruit in Italy.

Dynamics ofBlastophaga psenesPopulations, Availability of Caprifigs, and Fig Endosepsis Caused byFusarium moniliforme

Propagules of Fusarium moniliforme, which causes endosepsis of Calimyrna figs, were vectored on the body of the fig wasp pollinators, Blastophaga psenes. Scanning electron microscopy indicated that microconidia and mycelial fragments of F. moniliforme were attached to the wasps' bodies along with grains of pollen. Contamination of adult fig wasps occurred after they emerged from the flower galls, the specialized flowers within a fig syconium in which the wasp eggs hatch and develop. No adult wasps artificially removed from the flower galls were infested with propagules of F. moniliforme but 91-100% of those that emerged from infected syconia of pollinator cultivars (caprifigs) became contaminated

Effect of Topically Applied `Sevillano' Pollen on Normal-seeded and Parthenocarpic “Shotberry” Fruit Set of `Manzanillo' Olive

The `Manzanillo' olive (Olea europaea L.) is widely grown in California, because olive processors prefer its uniform size and quality for their canned product. Although it is self-compatible, 10% of a planting should be committed to a pollinizer cultivar to promote optimal production of seeded `Manzanillo' fruit and minimal occurrence of worthless parthenocarpic “shotberries.” As fruits of pollinizer cultivars are of substantially less value and more difficult to manage within a `Manzanillo' planting, less commitment of land for pollination purposes would be desirable. Here we show that topical applications of supplemental olive pollen can be a feasible alternative to commitment of land to olive pollinizer cultivars within a `Manzanillo' planting.

Long-term dichogamy of 80 pecan cultivars

Data are presented on dates of pollen shed and pistil receptivity for up to 16 years for 80 pecan ( Carya illinoensis (Wangenh.) C. Koch) cultivars and selections grown at Tifton, GA, USA. The data are useful for matching cultivars for optimum cross-pollination and minimum self-pollination. Pollination and pistil receptivity dates relative to the industry standard cultivar ‘Stuart’ are given so that the data should be useful at most geographical locations. Mean number of days of overlap of pistil receptivity and pollen shed ranged from 0 to 8 and varied greatly within a cultivar. Dates of pollen shed and pistil receptivity relative to ‘Stuart’ also varied greatly thus indicating that several pollinator cultivars are needed to ensure good cross-pollination every year. The data indicate that actual pollen release and pistil receptivity dates are more important in selecting pollinator cultivars than type of dichogamy.

The Foraging Behaviour of Honeybees on Ornamental Malus Spp. used as Pollinizers in Apple Orchards

The losses which can result from devoting a proportion of the acreage of an orchard to relatively uneconomic pollinizer trees interests growers in having pollen sources grafted into the trees of the main cultivar. The possibilities of using ornamental Malus spp. in this way are being investigated. They have several advantages over more conventional pollinizer cultivars: e.g. some species produce more flowers and hence more pollen per unit length of wood (Church, Goodall & Williams 1974), and the small fruits are readily distinguishable from the main crop at harvest. Although many insects will pollinate apple flowers (Kendall & Solomon 1973; Kendall 1973) there are frequently too few present in commercial orchards (Williams 1970; Smith & Lewis 1972). Honeybees are undoubtedly the most numerically important pollinators, particularly in orchards where colonies are introduced at blossom time. Consequently, the behaviour of honeybees in response to new management practices such as the introduction of ornamental Malus pollinizers is of interest and importance. The structure, presentation, colour and scent of the flowers of many ornamental Malus spp. are quite different from those of 'Cox's Orange Pippin' and other dessert apple cultivars. Hence, particular attention is given here to the relative attractiveness of their flowers to honeybees and the tendency of bees to remain constant to these species during a foraging trip. Both these aspects of bee behaviour can affect the transfer of pollen from one variety to another in apple orchards (Free 1960, 1963; Free & Spencer-Booth 1964; Free 1966). Three ornamental Malus spp. (M. aldenhamensis, M. floribunda Hillierii and an un-named species M. cv. Golden Hornet) are included in the present study because from observations on time of flowering, pollen quantity and quality (Wilson & Williams 1972; Church et al. 1974) these appear to be suitable as pollinizers for 'Cox'; and their flowers differ, particularly in colour, being crimson, pink and pinkish white respectively, so that any behavioural responses by honeybees to different flower structures or colours could be assessed.