Three rose varieties, ‘Meivildo’, ‘Meikatana’, and ‘Korcut0122’ were grown using an “arching” method for three years. The relationship between temperature and light intensity, and the yield and quality of cut flowers, were analyzed. Flowering flushes were observed 18 times in ‘Meivildo’ and ‘Meikatana’ and 16 times in ‘Korcut0122’ during the experimental period. In three varieties, significant negative linear regressions between the interval of flowering flush (growth period, GP) and the mean temperature per GP were observed. Significant positive correlations and linear regression were observed between the number of cut flowers per plant and the mean temperature in ‘Meivildo’ and ‘Meikatana’, and the total light integral per GP (TLI) in ‘Korcut0122’. In three varieties, significant positive correlations and linear regressions were observed between the total cut flower weight per plant, and the mean daily light integral per GP (DLI) and TLI. Highly significant positive correlations and linear regressions were observed between the daily gain in flower weight (DGW) of cut flowers per plant (the total cut flower weight divided by the number of days of GP) and the mean DLI in all three varieties. In ‘Meivildo’ and ‘Meikatana’, cut flower weight per stem had significant negative correlations and linear regression with mean temperature and positive ones with TLI, while ‘Korcut0122’ showed no significant correlation with the three environmental factors. Significant positive correlations and linear regressions existed between the specific cut flower weight (the cut flower weight per stem length) and TLI in all three varieties, and negative ones existed between the specific cut flower weight and mean temperature in ‘Meivildo’ and ‘Meikatana’. The relationship between the results in this experiment and previous reports on the relation between the environment and cut flower yield quality are discussed. Finally, we present the significance of the method used in this experiment for 1) prediction of flowering and shipping of cut flowers, 2) evaluation of differences in characteristics among the rose varieties, and 3) contribution to the development of a growth model.

Isolation, purification and identification of anthocyanins and flavonols were carried out on flowers of Ranunculus cultivars. Three anthocyanins and 11 flavonols were characterized by chemical and spectroscopic techniques. The anthocyanins were identified as cyanidin 3-O-sambubioside, cyanidin 3-O-(6''-malonylsambubioside) and delphinidin 3-O-(6''-malonylsambubioside). The flavonols were identified as 3-O-glucosides and 3-O-sophorosides of kaempferol and quercetin, and their acylated compounds with malonic acid. Flower colors were divided into six groups, Red-Purple, White, Yellow-Orange, Orange, Red, and Violet groups using the Royal Horticultural Society Colour Chart. The absorption maxima of buffer solutions containing anthocyanins and flavonols isolated in this study were measured to understand the effect of intermolecular copigmentation between these compounds on flower color. The results showed that by addition of 3-O-(6''-malonylglucoside) of kaempferol or quercetin, the absorption maximum of cyanidin 3-O-(6''-malonylsambubioside) or delphinidin 3-O-(6''-malonylsambubioside) shifted bathochromically and exhibited a closer absorption maximum to fresh flower petals than anthocyanin alone. This indicates that the intermolecular copigment effect between anthocyanins and flavonols is responsible for the flower color expression in Ranunculus cultivars.

Treatment with calcium chloride (CaCl₂) is known to suppress the occurrence of flower stem bending and extend the vase life of cut gerbera. To clarify whether vase life extension by CaCl₂ is improved by combined treatment with gibberellin A₃ (GA₃), the effect of treatment with 50 mg·L⁻¹ GA₃, 5 g·L⁻¹ CaCl₂ or in combination on the vase life of the cut gerbera ʻMinouʼ was investigated. To inhibit bacterial proliferation, which is known to shorten vase life, an isothiazoline antimicrobial compound was included in the vase solution. Treatment with GA₃ alone delayed the opening of tubular florets and increased the area of unopen florets, but stem elongation which led to stem bending shortened vase life. Treatment with GA₃ in combination with CaCl₂ suppressed the occurrence of stem bending. Combined treatment with GA₃ and CaCl₂ extended the vase life of cut gerbera more than treatment with CaCl₂ alone. To clarify whether GA₃ delays petal senescence, the effect of GA₃ at 10 and 50 mg·L⁻¹ on petal senescence was investigated using shortened stems. GA₃ at both concentrations significantly delayed petal senescence. Combined treatment with GA₃ and CaCl₂ also significantly extended the vase life of the cut gerbera ʻKimseyʼ and ʻSandyʼ. It was concluded that combined treatment with GA₃ and CaCl₂ is a suitable treatment for extending the vase life of cut gerbera.

Sweetness is one of the most important drivers of consumer preference in apples (Malus × domestica Borkh.). The increase in sugar during the ripening period of fruit is mainly brought about by the hydrolysis of starch accumulated before the ripening period. However, sugars are also continuously translocated into the fruit during the ripening period, as seen in watercored fruits. The objective of this study was to estimate the contribution of translocated sugars that accumulated in the apoplast to the increase in soluble solids content (SSC) of fruit during ripening. The amount of apoplastic solution (AS) tended to be high in the fruit of trees on vigorous rootstocks, such as ‘JM2’ and ‘Marubakaido’. On the other hand, fruit with more AS had lower SSC. Therefore, although AS increased during ripening, the contribution of AS to the increase in SSC was small. After fruit matured and during storage, dehydration increased the SSC of the fruit. On the other hand, the SSC decreased simultaneously due to a reduction in organic acids and any soluble solids, which was expressed as a decrease in titratable acidity (TA). Under standard refrigerated conditions, the increase in SSC due to dehydration and the decrease in SSC due to respiration were likely to be quantitatively comparable. The contribution of translocated sugars to the increase in SSC during ripening was small, suggesting that managing trees and fruit to increase starch accumulation before fruit ripening is crucial for the production of fruits with high sugar content.

Capsaicinoids are compounds that generate the characteristic pungent taste of chili peppers, the presence or absence of which determines the utilization of the chili peppers as spices or vegetables. Loss of pungency is a qualitative trait resulting from dysfunction in any of four capsaicinoid biosynthesis genes (Pun1, pAMT, CaKR1, and CaMYB31). However, the lack of pungency in sweet peppers cannot be explained by known mutation alleles in these four genes. Herein, we report a novel dysfunctional allele of Pun1, which encodes acyltransferase 3 (capsaicin synthase), in a Japanese sweet pepper, ‘Sampo Oamanaga’. Firstly, PCR genotyping of ‘Sampo Oamanaga’ Pun1 showed that it was not a known mutant allele. We also performed whole-genome resequencing and found a large genomic deletion around the ‘Sampo Oamanaga’ Pun1 (XM_016704778.1). We then examined the precise size and breakpoint of the Pun1-deletion region via de novo assembly and Sanger sequencing analysis. We found an 18.5-kbp deletion, including the Pun1, on chromosome 2, and we designated this novel allele pun1⁵. The genotypic effects of pun1⁵ were investigated using F₂ progeny derived from a ‘Sampo Oamanaga’ (pun1⁵/pun1⁵) × pungent cultivar ‘Takanotsume’ (Pun1/Pun1) cross. Only pun1⁵-homozygous F₂ plants showed non-pungency; co-segregation between Pun1 genotypes and pungency traits was observed. These results demonstrated that the deficiency of pungency in ‘Sampo Oamanaga’ is associated with the pun1⁵ allele. The present study is the first to discover a large genomic deletion, including a gene among dysfunctional pun1 alleles, and provides new insights into the regulation mechanism of pungency in chili peppers.

We investigated the anthocyanin composition of the purple sweet potato cultivar ‘Churakanasa’. The color tone of the paste was compared by L*, a*, and b* values and ‘Churakanasa’ exhibited a lower b* value, which indicates a bluish tint, than ‘Churakoibeni’, a popular cultivar for paste processing in Okinawa. High performance liquid chromatography (HPLC) analysis of the pigment extract showed that the anthocyanin composition of ‘Churakanasa’ was quite different from that of ‘Ayamurasaki’ and ‘Churakoibeni’. The analysis of the aglycone composition revealed that the cyanidin content (%) of ‘Ayamurasaki’ and ‘Churakoibeni’ contained 19.2% and 22.6% of cyanidins and 80.8% and 77.4% of peonidins, respectively. These findings indicate that these cultivars belong to the peonidin type. In contrast, ‘Churakanasa’ contained 86.4% cyanidin, indicating it to be a cyanidin-type cultivar. The steamed sweet potato paste made from ‘Churakanasa’ (cyanidin type cultivar) exhibited a bluer color compared to the peonidin-type cultivars. This observation suggests a direct correlation between the higher cyanidin content and the blue color intensity of the paste. HPLC-MS analysis of the two major HPLC peaks (peak I and II) of ‘Churakanasa’ suggested that the substance in peak I was YGM-0c; cyanidin-3-p-hydroxybenzoyl sophoroside-5-glucoside by mass, whereas peak II was YGM-1a; cyanidin-3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside. ‘Churakanasa’ exhibits unique color and pigment characteristics as it is the only purple sweet potato cultivar that has YGM-0c and -1a as its primary pigments.

In general, either high or low branching may contribute to the yield potential of a cultivated crop. In this study, we evaluated the varietal differences in branching characteristics in asparagus crowns and examined the relationship between branching types and harvest characteristics among six varieties tested by careful observation. ‘UC 157’ developed numerous tillers and shoot apical meristems 6 months after sowing; thus, it was considered to be a high-branching type variety. In contrast, ‘All-male Gulliver’ and ‘Ryuryoku’ developed few tillers or shoot apical meristems and, were therefore considered to be low-branching type varieties. The final order of sympodial shoots and composition of sympodial shoots by order were similar between the varieties. ‘UC 157’ had fewer scale leaves attached to the underground shoots than other varieties, which may have been advantageous for developing underground shoots more rapidly. The total spear yield of ‘UC 157’ was high, but the marketable spear yield was similar to that of other varieties owing to the large number of thin spears. Although further studies are needed to determine whether high-branching or low-branching type asparagus varieties are more high-yielding, we determined that high-branching type varieties have lower labor productivity under unimproved growing conditions such as non-sparsely planted growing conditions.

The goal of this study was to assess whether irradiated pollen technology could be used in tomato breeding research. The effects of irradiation on pollen viability, fruit set rate, and embryo formation were investigated. For this purpose, pollens were exposed to gamma rays of 0, 50, 100, 200, 300, and 400 Grays (Gy). The effect of irradiation on pollen viability and tube growth was found to be significant based on counting and measurements performed under in vitro conditions at 24, 48, 72, and 144 h after irradiation. Fruit set and embryo formation in seeds were evaluated 30 days after pollination with pollen irradiated at different doses. It was determined that increasing the irradiation dose resulted in reduced pollen viability and tube length. Endosperm formation was detected in all seeds after 50 Gy of irradiation. However, 50 Gy had no effect on gynogenesis stimulation. Therefore, 100, 200, and 300 Gy doses stimulated embryo formation without endosperm, while 400 Gy of irradiated pollen did not support fruit to set. These results indicate the importance of harvesting time to obtain viable embryos. It should be retracted to an earlier time since late harvest resulted in necrosis of globular embryos on the 30^th day after irradiation. Pollination with one-day-old irradiated pollen was more suitable for gynogenesis induction. The results showed that the irradiated pollen technique can be applied in tomato breeding studies, especially in terms of purifying the obtained breeding lines in a shorter time. In particular, determining the appropriate induction dose for gynogenesis depending on the genotype is important for stimulation efficiency.

“Twining” along other objects is an important morphogenetic survival response of vine plants. The twining response, induced by the stimulus of touching a supporting object, is a form of “thigmomorphogenesis”. Ethylene is thought to play an important role in thigmomorphogenesis in higher plants, so it is likely to be involved in vine twining. However, the relationship between ethylene and vine twining is not well understood. We used vine cuttings excised from morning glory (Ipomoea nil (L.) Roth ‘Violet’) plants in order to investigate the effect of an ethylene inhibitor on elongation and twining. The vine cuttings required gibberellin for elongation and twining. In the vine cuttings with elongation and twining induced by gibberellin treatment, treatment with 1-methylcyclopropene (1-MCP), an ethylene action inhibitor, significantly decreased the angle of rotation and the spiral pitch of the twining. These results suggest that ethylene may be involved in either sensing a pole via touch and the morphological changes during vine twining or both. We also selected one of the genes for 1-aminocyclopropane-1-carboxylic acid synthase (ACS), which is a key enzyme in the ethylene biosynthetic pathway, with higher expression in tissues on the side touching the pole in twining vines as one of the candidate genes thought to be involved in vine twining in morning glory.

Flowers of the early Polyantha roses, ‘Pâquerette’, ‘Mignonette’ and ‘Anne-Marie de Montravel’, have an unusual odor not found in other roses. Their ancestor is Rosa multiflora, a wild species native to Japan. In particular, ‘Anne-Marie de Montravel’ has a citrus scent with an old wooden closet-like odor. Gas chromatography (GC)-mass spectrometry analysis of the scent components of these roses revealed the presence of several terpenoids, benzenoids, and hydrocarbons, as well as the fatty acid derivatives methyl (E, Z)-2,4-decadienoate (MDD) and methyl (E, E, Z)-2,4,6-decatrienoate (EEZ-MDT). GC-olfactometry analysis of scent components of ‘Anne-Marie de Montravel’, identified EEZ-MDT and its isomers as the source of the unpleasant odor. MDD and EEZ-MDT are known as stink bug pheromones, but they were first detected in the scent of plants. We also analyzed the floral scent of several roses related to R. multiflora, namely: two plants of R. multiflora, two Hybrid Multiflora roses (‘Crimson Rambler’ and ‘Rose-Marie Viaud’), eight Polyantha roses (‘Cécile Brunner’, ‘Clothilde Soupert’, ‘Gloire des Polyantha’, ‘Madame Norbert Levavasseur’, ‘Marie Daly’, ‘Marie Pavié’, R. multiflora ‘Nana’, ‘Yvan Misson’), and one Miniature rose (‘Gourmet Popcorn’). EEZ-MDT and/or its isomers were detected not only in ‘Marie Daly’, ‘Marie Pavié’, R. multiflora ‘Nana’, and ‘Gourmet Popcorn’, which had an old wooden closet-like odor, but also in R. multiflora, ‘Rose-Marie Viaud’ and ‘Yvan Misson’, which do not exhibit that unpleasant odor. To produce the unusual odor in the rose fragrance, the EEZ-MDT and its isomers content must be above a certain percentage of the scent components.