The root shape, as well as the very big root, of Japanese radish ‘Sakurajima daikon’ is an important trait different from those of other cultivars. We clarified the mode of inheritance of the root shape in ‘Sakurajima daikon’ for effective breeding. We conducted a half-diallel analysis using 8 × 8 half-diallel crosses among its inbred lines with different root shapes. We measured the root length and root diameter as factors which represent the root shape. The root shape was analyzed using the image analysis software “SHAPE” based on Fourier descriptors. The 1st principal component (PC1) mostly showed the ratio of the root diameter to root length, and the 2nd principal component (PC2) mostly showed the degree of the root top width and root bottom roundness. The root length showed a high broad-sense heritability, a high narrow-sense heritability, and incomplete dominance. The root diameter and PC1 showed a high broad-sense heritability and a low narrow-sense heritability. The inheritance of the root diameter showed overdominance, that of PC1 showed overdominance to complete dominance, and that of PC2 showed overdominance. A lower broad-sense and narrow-sense heritability compared to other traits indicates that PC2 tends to be easily influenced by enviromental factors. Dominant genes for the root length, root diameter, PC1, and PC2 had effects to elongate the root length, enlarge the root diameter, increase the ratio of the root diameter to root length, and increase tapering of the root bottom, respectively. These findings indicate that the F1 hybrid is effective for breeding typical ‘Sakurajima daikon’ with a round root, and that it is neccesary to accumulate dominant genes concerning the root diameter and PC1 to either parental lines, and also to accumulate recessive genes concerning a round root bottom to both parental lines.
The screening of everbearing seedlings from a progeny population of F1 and S1, and inheritance of the everbearing habit in strawberry cultivars, were investigated under a 24-hour daylength condition. The everbearing seedlings were distinguished from June-bearing seedlings with high accuracy under the 24-hour daylength condition. From the segregation ratio of everbearing seedlings in the progeny populations of F1 and S1, it was shown that the everbearing habit is regulated by a single dominant gene. All everbearing cultivars in this study were heterozygous for the everbearing gene. Also, it was concluded that older everbearers and day-neutrals have the everbearing gene at the same locus. Everbearing seedlings were smaller in leaf blade and thinner in leaf petiole diameter than June-bearing seedlings. There was wide variation in the nodal position and flowering date of the first inflorescence among everbearing seedlings of F1 and S1 progenies. The everbearing seedlings of F1 between everbearers and June-bearer had a tendency to exhibit a later flowering date and higher nodal position of the first inflorescence than those of F1 between everbearers and everbearers. The heritability of the flowering date of the first inflorescence in everbearing seedlings was estimated to be 0.275 and 0.498 in 2008 and 2009, respectively, by parent-offspring regression.
In order to obtain reference data for future breeding programs involving Tamba black soybean, the eating qualities of its green soybean were evaluated by chemical and physical analyses. In ‘Murasaki-Zukin 2go’, ‘Murasaki-Zukin’, and ‘Shin-Tamba-Guro’, numerical data on chemical ingredient contents and the creep rupture property were collected by lab. analyses, and contrasted with sensory characteristic data. As a result, ‘Shin-Tamba-Guro’ received a high sensory evaluation with a good appearance, sweetness, rich taste, soft texture, and adequate viscosity. The degree of sweetness could be determined according to the increase or decrease in sucrose, maltose, alanine, and threonine contents in the boiled green soybeans. Those of tastiness and softness depended on two amino acid contents, glutamic and aspartic acid, and the break load level, respectively. For the evaluation of viscosity, the original ‘M level’ was available as a new index for the boiled green soybean. The evaluation method in this study must be applied as a new selection tool for developing a novel variety with good eating-quality in Tamba black Soybean.
For stable production of the interspecies hybrid ‘Sumomoume’ (Prunus salicina Lindl. × P. mume Sieb. et Zucc.), a self-incompatible haplotype (S-haplotype) and appropriative pollinizers were examined. The S-haplotype of ‘Sumomoume’ was thought to originate from Simon plum (P. simonii Carr.) and Japanese apricot (P. mume Sieb. et Zucc.). Simon plum is a species closely related to Japanese plum (Prunus salicina Lindl.), and these are able to cross mutually. Therefore, there should be cross compatibility with Japanese plum and Japanese apricot plum in ‘Sumomoume’ irrespective of these haplotypes. In this study, we determined appropriate pollinizers for ‘Sumomoume’. In fact, high levels of fruit set were obtained when ‘Sumomoume’ was artificially pollinated with Japanese apricot, Japanese plum and apricot (P. armeniaca L.). Japanese apricot ‘Miyagutikoume’ and apricot ‘Heiwa’ were the most suitable pollen donors in terms of the pollen quantity, pollen germination ability and cross-compatibility. These results suggest that the percentage of fruit set increased on artificial pollination using these pollen sources.
Prunus × yedoensis ‘Somei-yoshino’, one of the most famous flowering cherry cultivars in Japan, is self-incompatible. To determine how self-incompatibility and a compatible difference among crossing families occurred, we performed artificial pollination and measured the pollen tube growth and characteristics of the fruit set in ‘Somei-yoshino’. With the self-pollinated treatment, the pollen tube that germinated on the stigma never reached the bottom of the style, even by 10 days after pollination. Hence, the self-incompatibility in ‘Somei-yoshino’ is a result of the arrest of self pollen tube growth in the style. All self-pollinated fruit dropped within 20 days after pollination. In contrast, pollen tube growth to the bottom of the style was observed in almost all of the styles pollinated with inter-specific outcross pollen until 3 days after pollination. There were no differences among the crossing families in pollen tube growth within 10 days after pollination. The compatible differences in families were realized in the fruit set rate around 20 days after pollination. Subsequently, only small fruit dropped until maturation, and most fruit matured within 50 days after pollination, in early June.
In a previous study, we developed a method for measuring the stem water status (Rrev) using Time Domain Reflectometry (TDR) in the satsuma mandarin (Citrus unshiu Marcow.) tree. However, the relationship between fruit quality and Rrev under water stress has not been clarified. Thus, the purpose of this study was to identify this relationship in satsuma mandarin and ‘Shiranui’ [‘Kiyomi’ (C. unshiu Marcow. × C. sinensis (L) Osbeck) × C. reticulata Blanco]. Simultaneously, we determined the effects of fruit quality under water stress according to different intensities or periods on the fruit development stage. The results showed that the water stress integral (Sθ) of Rrev was correlated with an increase in the sugar content and fruit enlargement during July-September in satsuma mandarin and highly correlated with the same parameters during August-September in ‘Shiranui’. These results were similar to the correlation between fruit quality and the water stress integral (Sψ) of the maximum leaf water potential. Therefore, it was confirmed that Rrev is useful for water management. The effects of fruit quality under water stress in satsuma mandarin included the suppression of fruit enlargement and increase in the sugar content during the fruit developmental stage and suppression of acidity reduction in and after September. In ‘Shiranui’, it was determined that the water stress has a marked effect on the increasing sugar content in August-September, but it suppressed acidity reduction during autumn and fruit enlargement during the fruit enlargement stage. In conclusion, we propose that Rrev is a useful indicator for fruit quality control under water stress.
The effects of basal stem and root zone heating with different heating times and durations on the growth of primary shoots and lateral branches and roots, and on transpiration and photosynthesis were investigated in forcing culture of eggplant. Basal stem heating accelerated the growth of lateral branches and increased their number. Transpiration and photosynthesis rates of the leaves and amount of nutrient solution uptake increased by both basal stem and root zone heating as compared with the control. Growth habits differed by the heating positions: basal stem heating promoted the growth of lateral branches and root zone heating promoted that of primary shoots and roots. The longer the heating duration, the more the lateral branches grew. The heating time did not affect the growth of lateral branches when the heating duration was the same.
A delay in flowering and short cut flower length are problems in the winter culture of cut Eustoma (Eustoma grandiflorum) flower production in the warm southwest region of Japan. Growth promotion by high temperature management in the daytime was investigated by paying attention to the point at which no greenhouse heating was necessary in a certain period after planting in the region. The early flowering genotype ‘Bolero White’ was grown in growth chambers controlled at 25 or 30°C in the daytime and 15°C during the night. The plants placed at 30°C in the daytime showed a longer main stem and early flower budding and flowering compared with plants at 25°C. The weight of leaves and stems of the plants placed at 30°C was heavier than those at 25°C until 60 days after temperature treatment. The length of the inter-node at lower nodes was determined within 40 days of temperature treatment. To apply the results to actual cut flower production, ‘Bolero White’ was grown in a greenhouse where the temperature was set to 30°C. Rapid growth in the early developmental stage was confirmed in the greenhouse. The present results demonstrate that a higher temperature management in the daytime ensures the production of cut Eustoma flowers with a longer stem in winter culture in the warm southwest region of Japan.
We investigated the effect of the height of the primary scaffold branch on freezing injury, growth, yield, and fruit quality of the fig (Ficus carica L. ‘Masui Dauphine’). The primary scaffold branch was adjusted to 1.8 m with a straight line and horizontal direction of the fruit-bearing shoots, compared with the conventional system of adjusting the primary scaffold branch to a height of 0.6 m with a straight line and vertical direction of the fruit-bearing shoots. The trees of the 1.8-m-high scaffold branch system showed less freezing injury (0% mortality) in spring over the successive two seasons, while those of the conventional 0.6-m-high primary scaffold branch system suffered 100% freezing injury. Fig growth and yield were undermined, but the fruit quality was much improved in the high (1.8 m) primary scaffold branch system relative to that of the conventional system, before freezing injury occurred. One of the reasons for the reduced freezing injury being associated with the new training system may be ascribed to the observation that the high primary scaffold branch can narrow the early morning and daytime temperature difference on the upper surface of the branch. The adoption of the 1.8-m-high scaffold branch is therefore expected to improve fig fruit quality and reduce freezing injury.
The effect of several day and night temperature combinations on zucchini female flower formation was investigated in a temperature-controlled climate chamber under natural sunlight. The total number of flowers increased with higher night temperatures, but there was no difference in the number of female flowers and the length of the largest leaf. The ratio of female flowers to the total number of flowers was significantly lower at day/night 30°C/30°C than at 30°C/10°C and 30°C/20°C. The female flowering and fruit-setting rates were highest at 30°C/10°C and 30°C/20°C. Higher daytime temperatures (25°C/15°C and 35°C/15°C) increased the number of total flowers. These results indicate that female flower formation of zucchini was decreased by increasing the night temperature, and that both female flower blooming and fruit-setting were markedly inhibited at 30°C/30°C.
In the winter culture of cut Eustoma grandiflorum flower production, blasting of flower buds often occurs, resulting in an delay of the harvest time. In experiment I, a four-hour night break using incandescent lamp (IL) was given from planting to harvest. Two genotypes of Eustoma (‘Rosina Rose Pink’, ‘Piccorosa Snow’) showed early flowering with low frequencies of blasting compared with those cultured under a natural day length (NL). In experiment II, ‘Bolero White’ was grown under NL until apical flower budding. Then, 20-h LD with two types of light source, IL and a fluorescent lamp (FL), was given from the apical flower budding to harvest. In addition IL was given in the flower bud formation or mature stage. Lighting with IL did not affect the flowering time of the secondary lateral flower but lowered blasting emergence and elongated the stem at the upper nodes. Furthermore, the peduncle in the 3rd flower shortened by lighting with IL in the flower bud formation stage, but it elongated by the same treatment in the mature flower bud stage. The present results demonstrate that lighting with IL promotes flowering and lowers blasting emergence.
The influence of the fruiting position in the canopy on qualities of processed Japanese apricot liqueur (ume liqueur) of ‘Nanko’ Japanese apricot (Prunus mume Sieb. et Zucc.) was investigated for 4 years. Contents of citric acid and sorbitol in ume liqueur tended to be higher as the harvest time of processed fruit prolonged, and there were also no differences in them between ume liqueur made from fruit on the inner and outer sides of the canopy, when they were compared at the same stage, at the beginning of harvest. However, the phenolic content and antioxidant activity in ume liqueur made from fruit on the inner side of the canopy tended to be higher as the harvest time of processed fruit prolonged, and ume liqueur made from fruit on the inner side of the canopy tended to show higher contents than that made from fruit on the outer side of the canopy, when they were compared at the same stage, at the beginning of harvest. Contents of prunasin, causing bitterness, and ethyl benzoate, exhibiting immature flavors, in ume liqueur tended to be lower as the harvest time of processed fruit prolonged, and there were no differences in them between ume liqueur made from fruit on the inner and outer sides of the canopy, when they were compared at the same stage, at the beginning of harvest. Ume liqueur made from fruit on the inner side of the canopy tended to have less aroma components, such as γ-decalactone, δ-decalactone, and ethyl butyrate, than that made from fruit on the outer side of the canopy at the ripening stage. These results indicate that delaying the harvest time of fruit on the inner side of the canopy for about 7 days makes some functional and bitter components in ume liqueur equal to those made from fruit on the outer side of the canopy, and makes their phenolic content and antioxidant activity higher than that made from fruit on the outer side, and ume liqueur made from fruit on the inner side is poorer in the content of aroma components than that made from fruit on the outer side in cases of making fruity ume liqueur from fruit at the ripening stage.
Changes in ascorbic acid, glutamic acid, and sugar contents during storage in ‘Botankoshou’ (Capsicum annuum L.), a local chili pepper variety from Nagano Prefecture, were determined using a portable RQflex reflectometer. The measured components were compared with ‘Kyounami’ sweet peppers as a reference. Ascorbic acid, glutamic acid, glucose, and the total value of glucose and fructose were measured with on using a RQflex reflectometer. In addition, brix were measured by portable refractometer. While the values for each component were higher in ‘Botankoshou’ than in ‘Kyounami’ sweet pepper, the values of glucose and brix were the same between pepper varieties. Among the ‘Botankoshou’ fruit of different ages, the values were higher in mature ‘Botankoshou’ than in immature fruit. Generally, an increase in the length of storage resulted in a decrease in the flavor and antioxidant components of the peppers. Similarly, compared to 23°C, storage at 4°C also resulted in a decrease in flavor and antioxidant components. Concentrations of ascorbic acid, glucose, and fructose all decreased in the first seven days of storage, while those of glucose and brix only started decreasing after 13 days. Taken together, these findings illustrate the importance of Botankoshou storage conditions after harvest and during transport to market.
A new acid citrus, ‘Niihime’, Tachibana (Citrus tachibana Tanaka), and Shiikuwasha (C. depressa Hayata) were examined for flavonoid contents of the whole fruit and tissues (flavedo, albedo, vascular tissue, segment membrane, juice vesicle, and seed) at the maturing stage. Seven flavonoid substances, eriocitrin (ECR), narirutin (NRT), hesperidin (HSP), neoponcirin (NPNC), nobiletin (NBL), sinensetin (SNT) and tangeretin (TNG), were determined using HPLC analysis. The three acid citrus contained all flavonoid substances determined in the present study, except for no detection of ECR in Shiikuwasha. ‘Niihime’ contained more ECR, NRT, NPNC, and SNT than Tachibana and Shiikuwasha. Total contents of the seven flavonoids in the fruit of ‘Niihime’ were higher than in Tachibana. On the contrary, ‘Niihime’ contained significantly less NBL (65%) than Shiikuwasha, while it was similar to Tachibana. ‘Niihime’ contained significantly less TNG (30 and 24%, respectively) than Tachibana and Shiikuwasha. Flavonoid contents in individual fruit parts of ‘Niihime’ were as follows: ECR, SNT, NBL, and TNG were highest in the flavedo, NRT and NPNC were highest in vascular tissue, and HSP was highest in vascular tissue and the albedo.
Bacterial wilt of eggplant was suppressed by inoculation with non-pathogenic Ralstonia solanacearum (PC (phenotypic conversion) mutants). We tested simplified evaluation methods to select effective PC mutants for inoculation. Seeds and 1-leaf seedlings were inoculated with PC mutants. After these grew into plants with 3–4 leaves, they were inoculated with the wild-type strain. Seeds inoculated with PC mutants at the 1-leaf stage showed suppression of bacterial wilt. One-leaf seedlings were inoculated with PC mutants and then transplanted to soil inoculated with the wild-type strain as an easier method—seedling inoculation method. These plants also showed suppression of bacterial wilt. We investigated the suppression of bacterial wilt by PC mutants derived from 10 wild-type strains using the seedling inoculation method. Four strains that showed a highly suppressive effect were selected.
Bacterial wilt in eggplant was suppressed by inoculation with non-pathogenic Ralstonia solanacearum (PC (phenotypic conversion) mutants). We investigated the relation between colonization of the PC mutant and suppression of bacterial wilt by the PC mutant. Eggplant seedlings pre-inoculated with PC mutants at the root or 1-leaf petiole showed suppression of bacterial wilt when they were inoculated with the pathogen at the same site. Furthermore, seedlings pre-inoculated with PC mutants at the 5-leaf petiole showed suppression of bacterial wilt when they were inoculated with the pathogen at PC mutant inoculation and 1-leaf petiole sites. The PC mutants at the inoculation site demonstrated adequate colonization. Overall, bacterial colonization was indicated as a factor involved in the suppression of bacterial wilt.
We investigated the differences in fruit quality between gibberellin-treated and untreated berries of ‘Kyoho’ (Vitis labrusca L. × V. vinifera L.) grapes under the same fruit load. Although coloring of the seedless berries occurred earlier than in seeded berries, the increase in the skin color and soluble solids content (SSC) of seeded berries was superior to that of seedless berries after coloring. At the harvest time, the SSC of seedless berries was lower, but the skin color index changed from year to year. The skin color index and SSC of seedless berries decreased on the same shoot, and the skin color index of seedless berries decreased on the same cluster during the growing season. In addition, the skin color index and SSC decreased with an increase in the fruit cluster weight.
A sweet pepper, ‘Manganji’, is a local variety in Kyoto. However, fruits with pungency are frequently produced depending on the environmental conditions, e.g., high temperature or water stress. Previous studies reported that the complete lack of pungency was controlled by a single recessive gene. In this study, we developed a molecular marker (SCY-800) linked to this locus. A continuous backcross [(a bell pepper variety ‘Tongari’ × ‘Kyoto Manganji No. 1’) × ‘Kyoto Manganji No. 1’] with the help of marker-assisted selection was carried out in order to develop a novel non-pungent variety, ‘Kyoto Manganji No. 2’, by transferring the recessive gene to the original variety ‘Manganji’. In the new variety, pungent fruits were not observed at all in two different fields throughout two years. Other undesirable fruit characters (anthocyanin accumulation at pericarp, short fruit length, etc.) were found at very low frequencies as compared to ‘Kyoto Manganji No. 1’. Overall, our new variety, ‘Kyoto Manganji No. 2’, would be useful for the production of non-pungent pepper in Kyoto.