The inheritance of corolla traits, double, hose-in-hose, and single shapes, was studied by investigating the progenies and lines from self- and cross-pollinations of Eustoma flowers. A clear segregation was observed in progenies crossed between the single and double shapes, and we identified that the hose-in-hose shape was only inherited by forming the heterozygous genotype between the native strains and/or wild species with single and double flowers. According to data on the 965 individuals from F1 and F2 lines, it is likely that multiple alleles control the three kinds of corolla trait. Segregation patterns of the three flower shapes could be explained by the presence of three alleles designated as DD, DW, and DS in Eustoma flowers, controlling the phenotypes of double (DDDD and DDDS), hose-in-hose (DDDW), and single (DSDS, DWDW and DSDW) flowers (genotypes). Based on the results, it was concluded that the allele DW originales from the wild Eustoma species.
To expand the use of digestive liquid (DL) from methane fermentation, we examined whether DL could be used as a fertilizer in hydroponics. Because DL contains a large amount of NH4-N, plants would suffer from severe damage due to NH4-N and NO2-N if grown in nutrient solutions containing DL. Nitrifying bacteria propagated in sand filters equipped in some hydroponic facilities might prevent the accumulation of NH4-N and NO2-N, so the nitrification performance of the filter was monitored. The nitrifying capacity of a mature sand filter with a 0.0079 m2 filtration area was 180 mg・day−1 N. NO2-N tends to accumulate when NH4-N is highly loaded on the filtration system. Komatsuna (Brassica rapa L. Perviridis Group) plants were grown hydroponically using completely nitrified DL as fertilizer. The shoot fresh weight was comparable to that of the conventional cultivation method if phosphate and microelements were added to the nitrified DL-based nutrient solutions. Komatsuna plants were also grown in the NFT system equipped with sand filters and nutrients were replenished by the untreated DL during the cultivation period. The plant height was slightly lower than that with the conventional cultivation method, although the shoot fresh weight of both showed no significant difference. When DL was used for the nutrient solution, a large amount of K, Na, or Cl accumulated, presumably having negative effects on the plant height. Further study is needed to resolve the problems related to the accumulation of some nutrients in order to achieve the practical use of DL in hydroponics.
To develop the labor-saving cultivation of ‘Kosui’ (Pyrus pyrifolia Nakai), heavy metal application was conducted to induce fruit set without pollination. Bordeaux mixture containing 5.9 mM Cu2+ and 2 mM FeSO4 caused 20–30% parthenocarpic fruit set, respectively, on applying them 8 days before anthesis. Based on these findings, we identified some problems related to fruit set and development resolvable by heavy metals in this study. Firstly, we confirmed that the fruit set induction by Bordeaux was not different between spur and long bearing shoots. The fruit became suitable for market by treating it with GA paste 30 days after anthesis (DAA), and one fruit per cluster was shown to be appropriate. When the cultivation system was investigated in the orchard, the yield was almost the same as with conventional cultivation and the harvest time became much earlier. Thus, labor-saving cultivation of ‘Kosui’ pear may be possible by heavy metal application before anthesis, especially with Bordeaux mixture, because no artificial pollination, no pesticide application before anthesis, and almost no fruit thinning are necessary.
The objective of this study was to investigate the effect of brief exposure to air-conditioning or the air-conditioning time zone in summer during the night on the cut flower yield and characteristic form of roses. The petal length and number of petals of Rosa ‘Applaudissements’ grown under four-hour air-conditioning at 18 or 21°C at EOD (end of the day) were greater than those without air-conditioning, although the days to flowering and number of cut flowers were the same. The characteristic forms of flowers that were air-conditioned at 24°C and non-air-conditioned plants were the same. The days to flowering and number of cut flowers in Rosa ‘MEIKATANA’ were the same when the 21°C air-conditioning was carried out all night and at either EOD or EON (end of the night) for four hours, respectively. Although the air-conditioning was carried at EOD, EON, or all night, the values for the dry matter and length of cut flowers were higher than those from cut flowers without air-conditioning. On comparing electric power consumption with all night air-conditioning, those of EOD and EON were 58 and 31%, respectively. These results show that the EOD and EON air-conditioning treatment at 21°C are efficient temperature control techniques compared to all night air-conditioning.
We quantified how the spectral distributions ranging from red [R (600 to 699 nm)] to far-red [FR (700 to 799 nm)] influenced flowering and stem extension of stock (Matthiola incana (L.) R. Br.). ‘Yukinami’ and ‘White Iron’ plants were grown under a natural photoperiod with or without exposure throughout the entire night (continuous lighting) by LEDs with seven different R/FR ranging from all R to all FR (Experiment 1). Light exposure treatments promoted flowering and stem extension. The effects on flowering and stem extension increased as R/FR of the continuous lighting decreased, reaching a maximum at R/FR of 0.7 or lower in ‘Yukinami’. Exposure to R/FR ranging from 0.15 to 0.7 was more effective than FR-only continuous lighting for promoting flowering in ‘White Iron’. ‘White Iron’ plants were grown under a natural photoperiod with or without continuous lighting by LEDs with seven different peak wavelengths between 628 and 742 nm (Experiments 2 and 3). All exposure conditions promoted flowering and stem extension. Exposure to 709, 725, and 742-nm LEDs with peak wavelengths in the FR region strongly promoted flowering and stem extension. Flowering nodes were the lowest under continuous lighting with the 709-nm LED, which was the most effective for the promotion of flowering. The analysis using estimated values of phytochrome equilibrium established by LEDs with different peak wavelengths indicated the possibility of phytochrome control in the flowering and stem extension of stock.
The effects of the harvest time and storage temperature on the elasticity index (EI) and fruit quality were investigated to develop a quality retention technique for ‘Aikou’ mango. All fruits used in this study were individually wrapped in polyethylene film (11 μm thick). Fruits harvested at the pre-natural fruit drop stage (FH-pre-NFDS) and the post-natural fruit drop stage (FH-post-NFDS) were kept at 25°C for 10 days. In ‘Irwin’, the EI at both harvest times declined to around 80 × 105 and 72–75 × 105 after 2 and 10 days of storage respectively, whereas in ‘Aikou’, the rate of decrease was greater than that of ‘Irwin’, declining to 43–46 × 105 after 10 days of storage at both harvest times. In ‘Aikou’, the EI declined as the fruit ripening progressed and it was not influenced by the fruit size. When fruits were kept at 20°C for 0–10 days, the EI declined as the storage period extended, and it declined to 51–52 × 105 at 10 days of storage. Flesh firmness also declined as the storage period extended, and its change was synchronized with the EI. When the FH-pre-NFDS were kept at 15–25°C for 10 days, the EI declined rapidly; however, the rate of decrease in the ones kept at 10°C was slower than the others, and the EI was significantly higher after 4 days of storage. The FH-Post-NFDS kept at 10°C showed the second highest EI. The a-value of the FH-pre-NFDS kept at 10°C remained low, and was lower than that of the others. Hot water treatment (55°C) for 10 or 15 min did not affect the EI or fruit quality. A highly positive correlation was found between the EI and flesh firmness. The results of this study show that maintaining at 10°C after 15–20°C for a few days for coloring may be effective for the inhibition of softening in ‘Aikou’ FH-pre-NFDS, and the EI is useful to evaluate the firmness of juicy and soft fleshy mango fruit.
The expression of carotenoid biosynthetic genes in sweet pepper (Capsicum annuum L.) fruit during ripening and effects of light irradiation on fruit ripening were investigated. Fruits were harvested at the beginning of ripening, followed by light irradiation at a photosynthetic photon flux density of 100 μmol・m−2・s−1. Gene expressions of phytoene synthase (Psy), β-carotene hydroxylase (CrtZ-2), and capsanthin/capsorubin synthase (Ccs) were markedly induced after 1 day of light irradiation. Each expression was 207, 8, and 6-times higher than the dark control, respectively. Other carotenoid biosynthetic genes: phytoene desaturase (Pds), ζ-carotene desaturase (Zds), lycopene β-cyclase (LcyB), zeaxanthin epoxidase (Ze), and violaxanthin de-epoxidase (Vde), were also induced to 2–3-fold higher than the dark control. Light-irradiated fruits reached full redness in five days. These results suggest that light irradiation of harvested fruits induces a marked increase in the expression of Psy and other carotenoid biosynthetic genes such as CrtZ-2 and Ccs, followed by the accumulation of capsanthin in the sweet pepper fruit.
Garlic bulbs are stored at about −2°C for year-round shipping. Their commercial value often deteriorates due to root growth occurring after storage. Here, we aimed to clarify the optimum conditions of hot air treatment to inhibit root growth of garlic bulbs after storage at −2°C. Bulbs that had been harvested, cured, and then stored at −2°C from August were removed from storage about monthly from October to June, and then treated at 39, 41, or 43°C for 12 h. After maintaining them at 15°C for 4 weeks, root growth was investigated. Treatment at 39°C given after December and that at 41 or 43°C given after October inhibited root growth. Treatment at 39°C given after February, that at 41°C given after November, and that at 43°C given after October had an effect sufficient for practical application (keeping root length at less than 1 mm for 4 weeks after treatment). The inhibitory effect on root growth of treatment at 39 and 41°C was stronger the longer the storage until about February. On the other hand, the inhibitory effect of treatment at 43°C given in October was higher than that given after November. Judging from these results and heating costs, the optimum temperature of hot air treatment was considered to be 43°C in October and November, 41°C in December and January, and 39°C after February. The minimum treatment duration for practical application was 9 h on treatment at 43°C in October and November, 6 h on treatment at 41°C in December and January, and 6 h on treatment at 39°C after February to June. The selected treatment conditions after December were effective for inhibiting sprout growth as well.
‘Murasakizukin 3 gou’ was selected from the progeny derived from a backcross between the nonrecurrent parent ‘Murasakizukin 2 gou’ and recurrent parent ‘Murasakizukin’. ‘Murasakizukin 3 gou’ has the same growth properties, such as anthesis, harvest time, and the height of the main stem, as ‘Murasakizukin’, as well as similar amino acid contents, sugar contents, and creep rupture properties. The sensuality evaluation is higher. Its pods are brown at maturity. The seeds are spheroidal, black, and large in size (73.5 g/100 seed weight). In addition, ‘brown bloth symptom’, which is the major problem in ‘Murasakizukin’, is not observed in ‘Murasakizukin 3 gou’ due to resistance to A, A2, C, and D strains of the soybean mosaic virus. In Kyoto Prefecture, ‘Murasakizukin 3 gou’ will completely replace ‘Murasakizukin’ in 2016 and become available to consumers.
A seed propagation type of strawberry cultivar, ‘Yotsuboshi’, was collectively developed by four institutes belonging to Mie Prefecture, Kagawa Prefecture, Chiba Prefecture, and the National Agriculture and Food Research Organization. It is an F1-hybrid, whose maternal and paternal lines are a ‘Miebohon 1 gou’ and ‘A8S4-147’, respectively. ‘Yotsuboshi’ has several attractive traits, such as a clear red fruit color, excellent fruit shape, high yielding ability, and superior taste with a high content of soluble solids and moderate acidity. The behavior of flower initiation is quite unique: ‘Yotsuboshi’ exhibits earliness under natural conditions with a lower temperature and shorter day length, while flower initiation is also induced under long-day treatment. Genotype analysis with the published DNA markers for strawberry variety identification demonstrated that 23 of the 25 CPAS markers and 45 SSR markers were available to differentiate ‘Yotsuboshi’ from other varieties. We expect ‘Yotsuboshi’ to become widely cultivated across Japan.
Combined spraying of gibberellin (GA) and prohydrojasmon (PDJ) is an effective method of reducing peel puffing in satsuma mandarin fruit. However, there is a problem in that coloring of the fruit peel is delayed with the spraying. In the present study, the effects of spray concentrations and spray times of GA and PDJ on peel puffing and peel color were examined. Combined spraying of GA and PDJ at different concentrations was conducted from late August to early September in ‘Silverhill unshu’. Combinations of 1 ppm GA and 50 ppm PDJ, 3.3 ppm GA and 25 ppm PDJ, and 3.3 ppm GA and 50 ppm PDJ markedly inhibited peel puffing. The duration of coloring delay caused by these combined sprayings was more than 1 week. The combination of 1 ppm GA and 25 ppm PDJ also inhibited peel puffing. The duration of coloring delay caused by the combined spraying was almost within 1 week. Combined spraying of 5 ppm GA and 50 ppm PDJ for 3 cultivars, ‘Iwasaki wase’ (extremely early-ripening variety), ‘Okitsu wase’ (early-ripening variety), and ‘Silverhill unshu’ (mid-ripening variety), was also conducted at different spray times from August to October. The effects of the combined spraying on peel puffing and coloring delay were the highest with the spray time from the middle of August to late September in ‘Iwasaki wase’. In ‘Okitsu wase’ and ‘Silverhill unshu’, the effects of the combined spraying on peel puffing and coloring delay were the highest with the spray time in September.