Most rosaceous fruit tree species exhibit gametophytic self-incompatibility (GSI). During the last decade, much progress has been made in identifying and characterizing the S-locus genes that control the specificity of the self-incompatible (SI) reaction in the Rosaceae. The pistil and pollen determinants of S-specificity in the Rosaceae are a ribonuclease and an F-box protein, respectively. From allele-specific sequence polymorphism of S-specificity genes, molecular S-genotyping systems have been established in various rosaceous fruit tree species. Molecular characterization of S-determinants in self-compatible (SC) cultivars has revealed defects in the S-determinants that cause SC and enabled the development of molecular markers for SC. Marker-assisted selection of SC offspring is now being successfully incorporated into breeding programs. In this paper, we summarize the current knowledge of the molecular basis of self-(in)compatibility, S-genotyping methods, and molecular markers for SC in rosaceous fruit tree species.

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Sucrose is generally considered the primary photosynthate in plants; however, many horticultural crops, including rosaceous fruit trees, synthesize and use polyols (sugar alcohols). This review describes recent progress in physiological research on the metabolism and transport of sorbitol in rosaceous fruit trees, and of mannitol, another common polyol, in horticultural crops. Studies on various polyols other than sorbitol (in rosaceous fruit trees) and mannitol are then described. Polyols play a role not only in the translocation and storage of photosynthates but also in biotic and abiotic responses in many horticultural crops; therefore, this review also provides insights into the effects of polyol metabolism on the biochemical mechanisms of pathogenicity and environmental stress tolerance, including a novel strategy for engineering stress tolerance.

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High temperature affects berry composition, especially titratable acidity, total soluble solids, and anthocyanin content. Vitis ficifolia var. ganebu, a wild grape of sub-tropical origin with a low chilling trait, develops good coloration in its natural habitat, where daytime and nighttime temperatures are high during the berry ripening stage, while V. vinifera ‘Muscat of Alexandria’, a table grape, has large berries and high sugar content, hence, it was hypothesized that hybridizing V. ficifolia var. genebu with V. vinifera would improve the sugar content and reduce titratable acidity compared to V. ficifolia var. ganebu and retain berry color even under high temperature conditions. The aim of this study was to investigate the influence of temperature on the berry composition of ‘Kadainou R-1’, an interspecific hybrid wine grape derived from V. ficifolia var. ganebu × V. vinifera ‘Muscat of Alexandria’. Potted ‘Kadainou R-1’ vines with their ownroots were subjected to continuous temperatures of 20, 25, and 30°C in a phytotron during the berry-softening stage. Berries were harvested 15, 30, and 37 days after the vines were placed in the phytotron. Titratable acidity was lower at 30°C than at 20°C, while total soluble solids were highest at 25°C. Accumulations of glucose and fructose were higher at low rather than high temperatures. Total anthocyanin content (mg·g⁻¹ of fresh weight) was significantly reduced at 20 and 30°C but not at 25°C. Flavonol content was highest at 25°C. The present study revealed that ‘Kadainou R-1’ grapes can produce optimum berry quality in locations where the night temperature reaches 25°C without significant loss in berry quality.

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Six Oriental cultivars of Vitis vinifera, which are native to Japan or China, as well as 2 cultivars of V. labrusca as references, were characterized by 6 microsatellite markers with coded reference alleles. One allele in Oriental cultivars and 3 in V. labrusca have not been reported for Occidental cultivars. Assignment analysis using these data and reported data with grouping of V. labrusca, Oriental cultivars, and vine-growing regions of Occidental cultivars showed that 4 out of 8 Oriental cultivars, but only 3 out of 162 Occidental cultivars, were assigned to Oriental cultivars. These assignments are in accordance with the genetic distances calculated from microsatellite data. These results show that Oriental cultivars have a certain degree of genetic difference from Occidental cultivars within the species V. vinifera.

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Spinach (Spinacia oleracea L.) accumulates large amounts of oxalate, which reacts with calcium, inhibiting its absorption and forming urinary stones in humans. In this study, low-oxalate spinach mutant was induced through chemical mutation. Seeds of the gynomonoecious line of ‘Shin-Nippon’ were treated with 50 mM ethyl methane sulphonate (EMS) for 6 h. Self-fertilized M₂ seeds were harvested from M₁ plants individually. Total oxalate (water soluble and insoluble) concentrations of M₂ plants were measured, and four low-oxalate plants were selected. Self-fertilized M₃ seeds were harvested from these M₂ plants individually. In the progenies of three M₂ plants, oxalate concentration ranged from 9 to 19 mg·g⁻¹FW; there were no low-oxalate plants; however, in the progeny of one M₂ plant, five of eight plants had low oxalate; their concentration were lower than 2 mg·g⁻¹FW. Self-fertilized M₄ seeds were harvested from low-oxalate M₃ plants individually. The progenies of low-oxalate M₃ plants, named low-oxalate lines, were grown and compared with the original ‘Shin-Nippon’ and gynomonoecius line (wild types). Leaves of low-oxalate lines were slightly smaller and thinner than wild types, whereas the leaf number and color were similar. Oxalate concentrations of leaves in low-oxalate lines strongly decreased; one third to one sixth of those in wild types. Nitrate concentrations did not decrease in low-oxalate lines.

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Powdery mildew infection in cucumber plants was significantly reduced by foliar application of 2,6-dichloroisonicotinic acid (INA). Although the overall isozyme banding patterns of superoxide dismutase (SOD) and peroxidase (POD) were very similar, there were differences in the densities of major bands between the leaves of control and INA-applied plants. When plants were subjected to foliar applications of INA, the densities of SOD and POD isoforms was increased more abruptly 3 days after foliar application compared with the control plants; the high density was maintained thereafter. The specific activities of SOD and POD were increased rapidly by foliar application of INA. Although enzyme activities were increased with the development of colonies 9 days after the inoculation of pathogen in control plants, it did not reach the level of activity in the leaves of INA-applied plants. The expression of β-1,3-glucanase was only detected in the leaves of INA-applied plants. The specific activity of β-1,3-glucanase was also significantly increased in the leaves of INA-applied plants. Activities of SOD and POD by foliar application of INA were significantly reduced by diphenylene iodinium (DPI), an inhibitor of oxidative burst. The expression of β-1,3-glucanase was also restricted by foliar application of INA with DPI. However, the β-1,3-glucanase isozyme band was detected ambiguously with increasing of SOD and POD 6 days after foliar application. Although gel and specific activity of SOD and POD were significantly increased in the leaves of H₂O₂-applied plants, no β-1,3-glucanase isoforms were detected. These results suggest that activation of AOS-mediated enzymes by foliar application of INA seem to take part in defense reaction to induce the resistance to powdery mildew in cucumber plants.

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Monoecious cucumber (Cucumis sativus L.) produces male and female flowers on the same plant. In the early bisexual stage, all flower buds contain primordia for both stamens and pistils and sexual differences are established by the selective arrest of sexual organ primordia. Recently, the Cs1-MMP gene was isolated from a cucumber cotyledon. Cs1-MMP encodes a putative matrix metalloproteinase (MMP) and is expressed at the boundary of senescence and programmed cell death (PCD) of the cotyledon. In animals, MMPs make up a major group of enzymes that degrade the extracellular cell matrix (ECM). In cucumber flower organs, Cs1-MMP expression was analyzed in order to clarify the relationship between the arrest of sexual organs and PCD at the molecular level. In male flowers, strong Cs1-MMP expression was detected in both sepals and the area where pistil primordia became arrested. In female flowers, the highest levels of Cs1-MMP expression were observed in the sepals and the area where stamen primordia were arrested. In both male and female flowers, Cs1-MMP expression was detected from the early stage of development to anthesis. Our results suggest that Cs1-MMP plays an important role in PCD-mediated arrest of sexual organ primordia in cucumber flowers. Thus, it is possible that sex determination in cucumber requires continuous PCD to occur at the pistil or stamen primordia.

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In the present study, the standard addition method with Porapak Q column (PQ) extraction and gas chromatography-mass spectrometry analysis was adapted to quantitatively determine the character impact odorants of ‘Toyonoka’ strawberries. A significant correlation was confirmed between the contents that determine the character impact odorants in the PQ extract and the levels of standards added to the fruit samples; therefore, standard addition analysis might be a useful and reliable method to analyze already-known odorants in fruits. The concentrations of the character impact odorants, especially 2,5-dimethyl-4-hydroxy-2H-furan-3-one, hexanoic acid, γ-dodecalactone, and the esters, were detected at relatively high levels, which could explain why ‘Toyonoka’ strawberries have abundant aromas.

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Fusarium root rot of lettuce (RRL) caused by Fusarium oxysporum f. sp. lactucae (FOL) race 2 occurrs only in Nagano Prefecture, Japan. The area affected by the disease reached 17 ha in 2003. ‘Chouya No. 37’ crisphead-type lettuce (crisp lettuce), which is adaptable to summer cultivation, was bred with resistance to FOL race 2. As a maternal line to breed a resistant cultivar, the selection line of ‘Kikugawa No. 102’ was used as a genetic resource with resistance to FOL race 2. The resistant line was crossed with the selection line of crisp lettuce with slow bolting. The progeny had been selected by various methods until F₆, ‘Chouya No. 37’ was bred. ‘Chouya No. 37’ is as highly resistant to FOL race 2 as its maternal line. Its resistance is superior to that of other lettuce cultivars that are adaptable to mid-summer cultivation in Nagano. ‘Chouya No. 37’ is very vigorous, its leaf color is green to slightly dark green, and its leaf luster is relatively high. The leaf margins have relatively shallow incisions, indentations, and mild undulations. The quality of the head upon harvest is categorized as “relatively good” to “good”. It also has slow bolting in mid-summer.

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DNA fingerprinting of various crops is a powerful tool for preventing the infringement of breeders’ rights or incorrect labeling of cultivars; however, techniques with information for probabilistic identification are rare. We examined the independence of 25 cleavage amplified polymorphic sequence (CAPS) markers and the frequency of genotypes detected by each marker to prepare basic information for the probabilistic identification of strawberry (Fragaria × ananassa Duch.) cultivars. We could identify almost 117 investigated cultivars except mutant strains with a probability of at P > 99.9% with 16 markers.

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The effects of cutting time and low-temperature treatment of rooted cuttings on stem length and leaf number after planting were investigated in ten Chrysanthemum cultivars. Rooted cuttings propagated from mother plants on three different dates (September 30, November 10, and December 14) were planted two weeks after cutting and grown at constant temperatures of 20°C (7:00–19:00) and 12.5°C (19:00–7:00) under long days. In addition, rooted cuttings treated at 2.5°C for six weeks were planted on October 14 and November 24. The ten cultivars could be divided into three groups based on the increased stem length (ISL) of the rooted cuttings five weeks after planting. In five of ten cultivars, the ISL of rooted cuttings decreased from the first cutting date to the second cutting date, and increased from the second cutting date to the third cutting date. In three of the ten cultivars, the ISL of rooted cuttings increased progressively from the first cutting date to the third cutting date. The ISL and increase in leaf number of the rooted cuttings receiving low-temperature treatment were higher than those of untreated cuttings in all cultivars. The capability for stem elongation is apparently reduced by either of two types of temperature-related factors; high temperature followed by low temperature, and the other is high temperature only or high temperature followed by a short period of low temperature.

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To clarify the reason for delayed flowering of Chrysanthemum morifolium ‘Jinba’ cuttings propagated from mother plants during winter and spring production, the effects of growing temperatures of mother plants, and those of rooted cuttings grown in long days or short days, on vegetative growth and flowering in three autumn-flowering Chrysanthemum cultivars were investigated. Rooted cuttings of ‘Jinba’, propagated from mother plants exposed to two temperature regimes, were planted on December 26 and grown in two temperature regimes with long days. Plants with each treatment were then grown with short days using two temperature regimes. Flowering of rooted cuttings propagated from mother plants exposed to ambient low temperatures and grown at 25/10°C (7:00–19:00/19:00–7:00) with long days, and subsequently grown at 25/20°C or 25/10°C with short days, was delayed 11.4 and 14.4 days, respectively, compared with cuttings propagated from mother plants grown at a minimum temperature of 15°C. In a further experiment, the mother plants of three autumn-flowering cultivars were grown at four temperature regimes of 7°C, 10°C, 13°C, or 16°C for 50 days. Flower budding of ‘Jinba’ and ‘Seiko no Aki’ was delayed and the increase in leaf number (ILN) with short days was greater when mother plants were grown at 7°C or 10°C compared with plants grown at 16°C. In contrast, flower budding of ‘Shuho no Chikara’ cuttings propagated from mother plants grown at 7°C or 10°C was accelerated and the ILN decreased compared with those grown at 16°C. Clearly, delayed flowering of ‘Jinba’ and ‘Seiko no Aki’ was due to long-term exposure of mother plants to temperatures below 10°C. For suitable flowering of these cultivars, mother plants should be grown at a temperature exceeding about 15°C or the plants must be grown at a high temperature with long days for several weeks.

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Lilium longiflorum ‘Hinomoto’, the major lily cultivar in Japan, is regarded to have originated from natural individuals on Yakushima Island, and shows strong self-incompatibility; however, it was recently demonstrated that a population on Yakushima Island is dominant with weakly self-incompatible and completely self-compatible individuals, and this fact conflicts with the view that the strong self-incompatible ‘Hinomoto’ originated from Yakushima Island. The data by morphological and genetic analysis in this study indicate that ‘Hinomoto’ is genetically and morphologically different from natural individuals on Yakushima Island, but indicate that the origin of ‘Hinomoto’ could have been from any of the islands in the southern Ryukyu Archipelago.

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To develop an efficient procedure for the genetic transformation of lavandin, wild-type Agrobacterium rhizogenes harboring pIG121-Hm was used for infection. β-Glucronidase (GUS) expression was compared in leaf segments and leaf-derived calli as inoculation explants after five days of cocultivation, but GUS expression was only observed on calli. Hairy roots with strong GUS expression formed in 27.3% of these calli. When root segments excised from hairy roots were cultured in media containing various concentrations of 6-benzylamino purine (BA), thidiazuron (TDZ), or N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU), adventitious shoots were formed in some media. The adventitious shoot formation rate depended on the plant-growth regulator, and the highest adventitious shoot formation rate was 77.5%, in medium containing 0.02 mg·L⁻¹ CPPU. This medium was not as effective in the formation of adventitious shoots from calli. Shoots from hairy roots were easily rerooted and acclimatized in a temperature- and light-controlled room. Transformation efficiency was more than six times higher with the Agrobacterium rhizogenes-infected culture series (20.6%) than with the Agrobacterium tumefaciens-infected culture series (3.3%), in terms of the rates of hairy root induction and regeneration from hairy root segments. These results indicate that efficient genetic transformation in lavandin can be achieved with A. rhizogenes as the vector.

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As flower opening involves the expansion of petal cells, the mechanisms of expansion growth were investigated in Rosa hybrida L. ‘FEbesa’ (syn. ‘Pretty Woman’) petals. Petal cell-wall extensibility was analyzed by creep extension analysis. Walls of the petal cells became loose at developing stage IV of completely separated sepals on an opening flower. Furthermore, cell-wall proteins extracted from rose petals at stage IV were suggested to have a positive effect on cell-wall loosening of stage III petals. Expansin and xyloglucan endotransglycosylase/hydrolase (XTH) proteins, which are located on apoplasts, are probably involved in cell-wall loosening in plants. Transcripts of these cell-wall proteins were extracted from rose petals with a view to elucidating their potential role in rose flower opening. Expansin and XTH transcript levels changed markedly during petal development. In particular, transcript levels of RhEXPA1 and RhXTH1 increased markedly during petal growth and were relevant to the typical growth in different part of the petals. Based on the present findings, we suggest that RhEXPA1 and RhXTH1 are the major paralogs involved in expansion growth of rose petals.

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Tissue culture methods were investigated for propagation of the epiphytic orchid Neofinetia falcata H. H. Hu. The protocorms were divided into upper and lower portions and cultured. An average of 1.0–1.7 plantlets per explant were derived from upper portions which had survived at frequencies at 10–30%. Plantlets that developed from protocorms were cultured to increase the survival rate. All explants derived from upper portions of the plantlets survived, but explants from lower portions of plantlets did not. Explants derived from dark-preconditioned plantlets showed multiple bud formation when grown on medium containing 0.44 μM N⁶-benzyladenine (BA) and 5.37 μM α-naphthaleneacetic acid (NAA). Leaf explants derived from dark-preconditioned plantlets produced adventitious buds most efficiently when cultured in medium containing 0.44 μM BA and 5.37 μM NAA. These results suggest that the most suitable culture materials for bud formation in N. falcata are the upper portion of plantlets and the leaves of dark-preconditioned plantlets.

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