In order to estimate the differences in the suitability of eggplant fruit for Japanese-style cooking, the effects of processing methods on the taste quality and texture were investigated based on a sensory evaluation of seven cultivars including ‘Yatakei’, one of the native strains of ‘Kamonasu’ in Nara, treated as a high-grade ingredient in the market. Six processing methods: salting, pickling in seasoning liquid, deep frying and soaking in seasoned soup stock, boiling with seasoning, steaming, and grilling over an open flame, were compared. Moisture contents of fruits before and after salting and the contents of chlorogenic acid and total polyphenols, affecting astringency, were also measured. Among the cultivars, there were significant variations in the taste quality for all processing methods except deep frying, the astringency of salted, steamed, and grilled fruits, the firmness of flesh and succulence with all processing methods, and the pericarp firmness of salted, pickled, boiled, and steamed fruits. Significant variations were also observed in the oiliness when deep fried, flavor permeability when boiled, and sweetness when grilled. There were significant correlations between the taste quality score and texture parameters including astringency, firmness of flesh, succulence, and sweetness. Chlorogenic acid and total polyphenol contents of fresh flesh were positively associated with the astringency of salted, pickled, and deep fried fruits. ‘Yatakei’ was the most suitable for deep frying and grilling among the cultivars, as the taste quality score was the highest for firmness and sweetness.
Loquat canker is one of the most serious diseases of commercial varieties of loquat (Eriobotrya japonica). The pathogens are classified into three groups (A, B, and C) based on the production of a brown pigmentation in culture medium and pathogenicity to mesophyll. For marker-assisted selection (MAS) of Group A-resistant seedlings, we developed new simple sequence repeat (SSR) markers and fine-mapped the loquat canker-resistant gene Pse-a of bronze loquat (E. deflexa). The high-density linkage map included the Pse-a gene and 9 SSR markers, spanning 9.0 cM, with an average density of 0.9 cM per marker. The genotypes of these SSR markers were compared with the resistant phenotype of loquats from Japan (43 cultivars), other countries (13 cultivars), and unknown (1 cultivar). We found that two resistance-specific markers, SSR0254 and SSR0858, corresponded well with the resistant phenotype. The recombination values in two seedling populations between the marker and Pse-a were 2.3 and 12.6% for SSR0254, and 4.6 and 10.3% for SSR0858, respectively. Seedlings predicted to be resistant on the basis of SSR0254 or SSR0858 were resistant in an inoculation test with a probability of more than about 90% in every cross combination. We conclude that these markers may be useful in loquat breeding programs for MAS of individuals resistant to Group A.
In this study, we investigated the effect of local fertilization with calcium superphosphate applied 2–4 cm below the seeds on the phosphorous uptake, early growth, and yield of direct seeded onions (Allium cepa L.) in andosols. In andosol fields, where available phosphate was measured by the Truog method to be less than 10 mg・100 g-1 dry soil, local fertilization accelerated the emergence of the second or third leaf and was shown to promote growth. This could be seen through the increased number of developing leaves throughout the growing season, which led to a greater plant height and dry weight. Furthermore, in a trial comparing broadcast with local fertilization, the latter yielded more bulbs greater than 8 cm in diameter at harvest than the former. We concluded that local fertilization with calcium superphosphate 2–4 cm below the seeds improved early growth and the final yield of direct seeded onions compared with broadcast fertilization.
The capacity to reduce chemical fertilizer application by adding livestock manure compost and hairy vetch (HV) was examined in squash cropping for 3 years. Livestock manure compost was incorporated and HV seeds were planted in October. The following spring, grown HV in the squash row was incorporated before planting squash, and total nitrogen in HV was 0.93 to 1.04 kg・a-1. Inter-row spaces were covered with HV (living mulch). When HV was incorporated into the squash row, it became possible to reduce application to 0.6 kg-N・a-1 for squash production. Alternative nitrogen fertilizer effects by the application of livestock manure compost were small; however, the compost application had the potential to substitute for other fertilizer components except nitrogen. The substitution of nitrogen by HV incorporation, and substitution of other fertilizer components by the application of livestock manure compost, were considered to be effective to reduce the fertilizer needed.
Pollination with soft-X-irradiated pollen caused the disappearance of almost all complete seeds in harvested fruit, resulting in the transformation into empty seeds, in 7 persimmon cultivars: ‘Fuyu’, ‘Matsumoto-Wase-Fuyu’, ‘Izu’, ‘Taishuu’, ‘Maekawa-jiro’, ‘Saijo’, and ‘Zenjimaru’. Although the ovules that formed by pollination with irradiated pollen normally developed just as non-irradiated ones until 2 weeks after pollination, severe abnormality in endosperm tissue and the cessation of embryo development were observed at 4 weeks after pollination. Setting rates of fruit formed by pollination with irradiated pollen were not different from ones with non-irradiated pollen in ‘Saijo’, ‘Zenjimaru’, or ‘Matsumoto-Wase-Fuyu’; a significant decline in the fruit setting rate occurred in ‘Taishuu’ pollinated with 1,000 Gy-irradiated pollen grains, and in ‘Fuyu’, ‘Maekawa-jiro’ and ‘Izu’ pollinated with 500 and 1,000 Gy-irradiated pollen grains. Pollination with irradiated pollen decreased the harvested fruit weight, width, and length in ‘Saijo’ and the length in ‘Fuyu’; in other cultivars, the fruit weight and size were not influenced on pollination with irradiated pollen. Regarding the juice Brix, flesh firmness, and rind color of harvested fruits, there were no significant differences between irradiated and non-irradiated pollination in any of the cultivars. Pollination with irradiated pollen reduced stylar-end cracking in ‘Maekawa-Jiro’ fruits, possibly resulting in the disappearance of large complete seeds. These results indicate that pollination with soft-X-irradiated pollen would be available for practical seedless or few seeded fruit production in persimmon.
Tuber development and flower stalk production in 2- to 4-year-old plants of Gentiana triflora were investigated to elucidate factors involved in the decrease of flower stalk production in 4-year-old plants. The primary tuber grew vigorously and formed secondary tubers in 2- to 3-year-old plants. The secondary tubers were mainly formed in this stage. In 3- to 4-year-old plants, the size and dry weight of the primary tuber reached a plateau, while secondary tubers grew vigorously. Tuber growth and flower stalk formation were correlated; in 3-year-old plants in which primary tubers grew vigorously, flower stalk formation from the primary tuber was also vigorous. In contrast, in 4-year-old plants in which primary tubers grew moderately and the basal part was extensively lignified, flower stalk formation from the primary tuber was also moderate. This was the main factor causing the decrease in flower stalk production in 4-year-old plants, although vigorously growing secondary tubers showed vigorous flower stalk formation. The primary tuber continuously initiated lateral buds which developed into secondary tubers and flower stalks, with the apical bud staying vegetative. Thus, the retarded growth of the primary tubers in 4-year-old plants maintained an indeterminate growth habit.
Availability of cross-pollination with soft X-ray-irradiated pollen for seedless fruit production in Hyuganatsu (Citrus tamurana hort. ex Tanaka) was estimated and compared with conventional methods inducing seedlessness by pollination with pollens of ‘Kankitsu Kuchinotsu 41 Gou’, a tetraploid cultivar, and ‘Nishiuchi Konatsu’, a self-compatible mutant Hyuganatsu cultivar. Pollen of ‘Tosa Buntan’ pummelo, which is a conventional pollinizer for Hyuganatsu production, ‘Kankitsu Kuchinotsu 41 Gou’, and ‘Nishiuchi Konatsu’ was irradiated with 500, 1,000, and 2,000 Gy soft X-rays. The germination rates using irradiated pollen decreased with the dose. Irradiated or non-irradiated pollen was used to pollinate flowers of ‘Sukumo Konatsu’ Hyuganatsu, and natural pollination was prevented by covering the whole tree with a net. The fruit setting rates using irradiated pollen decreased with the dose. Perfect seed numbers in harvested fruit pollinated with non-irradiated ‘Tosa Buntan’, ‘Kankitsu Kuchinotsu 41 Gou’, and ‘Nishiuchi Konatsu’ pollens were 23.8, 0.4, and 1.5 respectively; seeds scarcely remained using irradiated pollen. In fruits following pollination with non-irradiated ‘Kankitsu Kuchinotsu 41 Gou’ and ‘Nishiuchi Konatsu’ pollen, a few large empty imperfect seeds over 10 mm long remained in 3.9 and 2.3, respectively; 500 Gy soft X-ray irradiation of pollen decreased large imperfect seeds, and 1,000 Gy irradiation led to the disappearance. On microscopic observation, although a few embryos survived in seeds following pollination with non-irradiated ‘Kankitsu Kuchinotsu 41 Gou’ and ‘Nishiuchi Konatsu’ pollen even 8 weeks after pollination, no active embryo was observed in seeds following pollination with irradiated ‘Tosa Buntan’ pollen; pollination with irradiated pollen can be considered to inhibit seed development more markedly than with non-irradiated ‘Kankitsu Kuchinotsu 41 Gou’ and ‘Nishiuchi Konatsu’ pollen. Pollination with irradiated pollen decreased the harvested fruit weight; however, that would not be so deleterious because consumers actually prefer smaller fruits with fewer seeds at Hyuganatsu market in Kochi. These results indicate that pollination with soft X-ray-irradiated pollen is a useful technique for seedless Hyuganatsu fruit production without the development of a few large imperfect seeds, and the suitable irradiation dose is 500 to 1,000 Gy.
We investigated the effects of the application of chemical flower and fruit thinners on the fruit thinning time and fruit weight in four major apple cultivars. The effects of chemical flower and fruit thinning varied among cultivars due to the differences in the fruit drop rate of apical buds and the fruit set rate of axillary buds. In ‘Tsugaru’ and ‘Jonagold’, the single application of the flower thinner did not result in a labor-saving effect because the fruit set rate of axillary buds was high. Considering fruit enlargement, the combined application of the flower thinner and fruit thinner was the most effective in these two cultivars. In ‘Shinano Sweet’, the application of the flower thinner had no labor-saving effect on fruit thinning, but promoted fruit enlargement. In ‘Fuji’, the combined application of the flower and fruit thinners after hand pollination was the most effective for both labor-saving and fruit enlargement. The single application of the flower thinner had a more labor-saving effect than the fruit thinner.
The sweet cherry is often subjected to high temperatures during the flowering period that cause fruit set to become unstable. As global warming proceeds, temperatures are likely to continue rising. At the southern limits of the area in which the sweet cherry can be cultivated economically, there is concern over the effects of increasingly higher temperatures during the flowering period. However, the temperature range and timing of the high temperatures that would induce ovule degeneration have not yet been examined in detail. We examined varietal differences in the sweet cherry for ovule degeneration after being subjected to high temperatures during the flowering period. After 5 hours of treatment at a temperature from 22 to 31°C just before flowering, the rate of viable ovules decreased. Ovules were markedly damaged on the days with high temperatures. In addition, different varieties exhibited varying sensitivities to high temperatures during the flowering period. In ‘Satohnishiki’, immediately after the high-temperature treatment, the rate of wholesome ovules in a 22°C treated plot was significantly higher than that in a 31°C treated plot. On the other hand, rates of wholesome ovules of ‘Takasago’ were reduced with high temperatures of more than 28°C. The rates of wholesome ovules of ‘Benishuho’ and ‘Kaiouka 1’ were significantly reduced at high temperatures of more than 31°C. After high-temperature treatment of ‘Satohnishiki’, a tendency for the rate of wholesome ovules to decrease markedly at all temperature ranges was observed. The rate of wholesome ovules in ‘Benishuho’ decreased gradually with the passage of days. The effect of high temperatures on ovule degeneration was evident after even a short time. Just 1 hour at a high temperature caused ovule degeneration. Four varieties were examined, and all showed advanced ovule degeneration due to high temperatures in the flowering period, but the progress of ovule degeneration differed by cultivars.
Daytime temperatures in the greenhouse are often lower than the suitable growth temperature for forcing culture of tomato in Fukuoka. The effect of daytime heating on the marketable fruit yield during the winter season was investigated in this study. An increase of the minimum day temperature from 8°C to 20°C by a heater resulted in a significant increase of the number of marketable fruits, by improvement of the marketable fruit rates and intervals between anthesis and fruit ripening. In addition, fruit growth after flowering was accelerated when tomato plants were heated in the daytime. It was assumed that photosynthesis of the leaves accelerated, and translocation to fruit increased due to the rising air temperature. As a result, the marketable fruit yield on daytime heating was larger than in the control from April to May.
The effects of hydrogen cyanamide (H2CN2) on blooming and vegetative bud leafing of ‘Kawazu-zakura’ (Prunus lannesiana Wils.) cherry trees were investigated in the Minamiizu region. In experiment 1, dormant limbs were sprayed with 0.75 or 1.00% H2CN2 on Nov. 17 and Dec. 18, 2008. On the branches sprayed with H2CN2 on Nov. 17, blooming and leafing occurred over 2 weeks earlier than in the controls. In experiment 2, dormant limbs were sprayed with 0.75, 1.00, or 2.00% H2CN2 on Nov. 16, 2009. At the lower concentrations of 0.75 and 1.00%, the effects of H2CN2 to promote blooming and leafing increased with its concentrations. At the highest concentration, however, vegetative buds showed a failure rate of about 40%. In experiment 3, whole trees were sprayed overhead with 0.75% H2CN2 on Nov. 18, 2009. For trees sprayed with H2CN2, blooming and leafing occurred over 2 weeks earlier than in the controls. These results were similar to those obtained in the sprayed limbs. When ‘Kawazu-zakura’ trees were sprayed with H2CN2 in Nov., 0.75 or 1.00% H2CN2 induced blooming 2–3 weeks earlier compared with natural blooming. Thus, the blooming period of ‘Kawazu-zakura’ in the Minamiizu region can be extended by forcing with H2CN2 to 32–39 days, including its natural blooming duration (about 18 days).
The effects of day temperature, night temperature, and the difference between day and night temperatures on coloring of flowering cabbage ‘Winter cherry’ and ‘Haresugata’ were investigated under illumination with blue, green, and yellow rich type white fluorescent lamps. In the experiment which investigated the night temperature, the leaves changed color at 20/5°C (day/night) and 20/10°C until 20 days after temperature treatment started, but it did not change at 20/15°C. In the experiment which investigated the day temperature, the leaves changed color at 15/5°C and 20/5°C until 20 days after temperature treatment started, but it did not change at 25/5°C. In the experiment with no difference between day and night temperatures, the leaves changed color at 15/0°C and 20/5°C until 20 days after temperature treatment started, but it did not change at 25/10°C. In all experiments, the coloring area rate was the highest at 20/5°C until 20 days after temperature treatment started. These results showed that a day temperature of under 20°C and night temperature of under 10°C were necessary for coloring. Furthermore, it was revealed that coloring of flowering cabbage ‘Winter cherry’ and ‘Haresugata’ was influenced by the day temperature more than the night temperature or difference between the two.