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In Eustoma (Eustoma grandiflorum (Raf.) Shinn) cultivation in southwestern Japan, cold imbibition treatment of seeds is important to accelerate bolting and flowering of seedlings grown in the summer season. In order to facilitate the handling of cold imbibed seeds, re-drying treatment (RDT) after wet treatment at 10°C for 35 days in dark conditions (WT10°C) is considered to be an essential technique. The investigation of five Eustoma cultivars ‘Exe Lavender’, ‘Orb Snow’, ‘Philia Lavender’ , ‘Dure Lavender’ and ‘Exe Light Pink’ was to find the germinability and the growth characteristics of Eustoma when re-drying and storage at 10°C for 30 days were applied immedietely after ending the WT10°C. The results showed that germination and growth responses differed among Eustoma cultivars. RDT seeds and non- RDT seeds of ‘Exe Lavender’, ‘Orb Snow’ and ‘Philia Lavender’ had a similar germination rate. However, germination rate of RDT seeds in ‘Dure Lavender’ and ‘Exe Light Pink’ was lower than that of non-RDT seeds. There was no significant difference in cut-flower quality grown from RDT and non-RDT among ‘Exe Lavender’, ‘Orb Snow’ and ‘Dure Lavender’. However, bolting and flowering rate of RDT in ‘Dure Lavender’ and ‘Exe Light Pink’ were lower than those of non-RDT. This suggested that it might not be useful to apply RDT after the cold-wet treatment of Eustoma seed due to lower germination or bolting rates in some cultivars. Further investigation of cold-wet exposure and dehydrating conditions is required to establish RDT procedures for Eustoma cultivars.

Fasciation in strawberry is characterized by an enlarged and flattened receptacle, clustering of flowers, and altered inflorescence architecture. However, the developmental process of fasciated flowers remains obscure. In this study, the fasciation incidence and developmental process in the primary fruit and inflorescence architecture were evaluated and compared for the non-susceptible cultivars, ‘Nyoho’ and ‘Sagahonoka’ and one of the most susceptible cultivars, ‘Ai-Berry’. The severity and frequency of flower and inflorescence fasciation was clearly greater in the vigorously growing large plants of ‘Ai-Berry’ compared to small plants and large plants of the other two cultivars. In ‘Ai-Berry’, the deformation of the large shoot apical meristem (SAM) into an oval shape was the initial symptom observed before and during floral transition. Such oval-shaped SAMs often differentiated two or more leaf primordia almost at the same time, which then developed into divided multiple vegetative SAMs before floral transition and linearly-fasciated SAMs during floral transition, respectively. The development of fasciation symptoms was observed after downregulation of FaTFL1. Although inflorescence or receptacle fasciation could be controlled when early and rapid floral induction was achieved by intermittent low-temperature treatment, severe fasciation was observed in late-flowered plants which were either not responsive or not subjected to this treatment. These results indicate that fasciation of floral organs may be triggered and develop during floral transition and that temperature fluctuations around boundary values between floral inhibition to induction may cause a half-finished or slowly processed floral transition and finally result in severe fasciation in vigorously growing ‘Ai-Berry’ plants.

The objectives of this study were to (i) determine the optimum number of whole leaves to retain on a tomato plant for effective blossom-end rot (BER) management and (ii) explore the relationship between shoot calcium (Ca) and fruit Ca in non-defoliated plants in two different sized fruit cultivars, a large-fruited cultivar ‘Momotaro fight’ and a medium-fruited cultivar ‘Cindy sweet’. Treatments involved maintaining 18, 15 and 12 leaves on a plant. All lateral shoots were removed regularly throughout the growing period except the shoot closest to the flowering truss in the 18-leaf treatment. At the length of 10cm, these shoots were sampled for real time Ca determination using a hand held Ca2+ meter. In the plants defoliated to 18 leaves, BER was higher in ‘Momotaro fight’ at 10% compared to 2% in ‘Cindy sweet’. Fruit growth rate was significantly increased by defoliation in ‘Momotaro fight’, however no significant difference was observed among treatments in ‘Cindy sweet’. Defoliating to 12 leaves increased daily Ca transport rate by 59% and 37% in ‘Momotaro fight’ and ‘Cindy sweet’, respectively. Defoliating to 12 leaves increased the water-soluble Ca concentration in the distal part of fruit by 34% and 14% in ‘Momotaro fight’ and ‘Cindy sweet’, respectively. In the plants defoliated to 18 leaves where only old yellowish leaves were removed, a significant steady decrease was observed in the concentration of water soluble Ca in the distal part of fruit with increase in truss order. There was a significant linear relationship between water-soluble Ca concentration in the distal part of the fruit and Ca concentration in the lateral shoot of plants defoliated to 18 leaves. We conclude that under moderate water stress by root zone restriction and also certain other BER inductive conditions, defoliation to 12–15 leaves on a tomato plant should be a promising approach for decreasing BER incidence in susceptible large fruit cultivars.

Capsaicinoids are unique compounds that give chili pepper fruits their pungent taste. Capsaicinoid levels vary widely among pungent cultivars, ranging from low‐pungency to extremely pungent. However, the molecular mechanisms underlying its quantitative variation have not been elucidated. Our previous study identified various loss‐of‐function alleles of the pAMT gene, which led to low‐pungency. The mutations in these alleles are commonly defined by Tcc transposon insertion and its footprint. In this study, we identified two leaky pamt alleles (pamtL1 and pamtL2) with different levels of pAMT activity. Notably, both alleles had a Tcc transposon insertion in intron 3, but the locations of the insertions within the intron were different. Genetic analysis revealed that pamtL1, pamtL2 and a loss‐of‐function pamt allele reduced capsaicinoid levels to about 50%, 10%, and less than 1%, respectively. pamtL1 and pamtL2 encoded functional pAMT proteins, but they exhibited lower transcript levels compared with the functional‐type. RNA‐seq analysis showed that intronic transposons disrupted splicing in intron 3, which resulted in simultaneous expression of functional pAMT mRNA and non‐functional splice variants containing partial sequences of Tcc. The non‐functional splice variants were more dominant in pamtL2 than that in pamtL1. This suggested that the difference in position of the intronic transposons could alter splicing efficiency, which led to different pAMT activities and reduced capsaicinoid content to different levels. Our results provide a striking example where intronic transposons caused allelic variations, which contributed to quantitative differences in secondary metabolite contents., トウガラシの辛味レベルを変化させる遺伝子変異を発見 －激辛・中辛・辛くないを作り分ける－. 京都大学プレスリリース. 2019-08-30.

The chili pepper (Capsicum) is both an important spice and fresh vegetable worldwide. C. baccatum is a lesser known domesticated species that is native to the Andean region. Fruit traits such as color, shape, and pungency markedly vary in this species. C. baccatum has potential as a bioresource for future chili pepper breeding programs. Although extensive studies have been conducted on the pungency of C. annuum, that of C. baccatum has not been examined in as much detail. In the present study, capsaicinoid contents were analyzed in 36 C. baccatum accessions. Capsaicinoid contents ranged between 0 and 4,258 μg/gDW. Furthermore, a negative relationship was observed between capsaicinoid contents and fruit weights. Although the pungency of C. baccatum is regarded as low-mild, very few non-pungent accessions were detected ; only one non-pungent accession (‘Kaleidoscope’) was identified among the C. baccatum accessions examined. In order to validate the stability of non-pungency in the accession, capsaicinoid contents were determined at different harvest dates, along with other accessions with different pungencies. Although capsaicinoid contents in other C. baccatum accessions changed with the picking date, capsaicinoid was not detected in ‘Kaleidoscope’ at any date. The non-pungent accession reported here may be useful for future C. baccatum pepper breeding programs., トウガラシ（Capsicum 属）は世界的に重要な香辛料および野菜である．C. baccatum は南米原産のマイナーな栽培種であるが，果色，果形や辛味など果実形質に多様性が認められることから，トウガラシ遺伝資源として注目されている．トウガラシの辛味性についてはC. annuum 種において多くの研究が行われているが，C. baccatum 種においては十分研究されていない． 本研究では，C. baccatum 36系統について辛味成分カプサイシノイドの含量を調査した．カプサイシノイド含量の幅は0 ～4,258 ㎍ /gDW であった．また果実重と辛味成分含量の間に負の相関が認められた．C. baccatum の辛味は低〜中程度であるが，非辛味系統はほとんど認められず，唯一1 系統（‘Kaleidoscope’）が非辛味であった．この非辛味の安定性を調査するために，辛味程度の異なる系統とともに異なる収穫時期におけるカプサイシノイド含量を調査した． 他のC. baccatum 系統ではカプサイシノイド含量は収穫時期で変化したが，‘Kaleidoscope’ ではいずれの収穫時期でもカプサイシノイドは検出されなかった．本研究で見出された非辛味系統は将来のC. baccatum の育種において有用であろう．

Yellow-leaf-spot, a physiological abnormality occurring in leaves of several chrysanthemum (Chrysanthemum ×morifolium) cultivars harvested from September to October, is a very serious problem in Japan, of which causes have not been well established. Water stress, high temperature, high irradiation or nutrient stresses are possible physiological factors which may lead to yellow-leaf-spot. In the present study, effects of nutrient levels and mineral composition on the occurrence of yellow-leaf-spot were investigated. ‘Seikou-no-makoto’ and ‘Seikou-no-masaru’ plants were grown in 5 nutrient solutions (N 0, 60, 120, 180, 240 ppm based on Enshi-shoho). In ‘Seikou-no-masaru’ no yellow-leaf-spot occurred. However, in ‘Seikou-no-makoto’, the nodal position with spotted leaves and rate of yellow-leaf-spot increased as nutrient levels increased. ‘Seikou-no-makoto’ plants were supplied with 6 different nutrient solutions containing 3 times N, P, K, Ca, Mg or Fe in 1/3 concentration of Enshi-shoho solution for 3 or 14 days. The nodal position with spotted leaves and rate of yellow-leaf-spot was not affected by mineral composition. The nodal position with spotted leaves and rate of yellow-leaf-spot increased with increasing days of application. Both cultivare were supplied with 7 different nutrient solutions with lacked N, P, K, Ca, Mg, Fe or only microelement (no mineral) in 1/2 Enshi-shoho solution for 10 days. In ‘Seikou-no-masaru’, no yellow-leaf-spot occurred. It occurred only in ‘Seikou-nomakoto’. yellow-leaf-spot occurred in control, P, K, Ca, Mg, Fe deficiency and no mineral, but only slightly in all cases. These results suggest that the occurrence of yellow-leaf-spot was dependent on genotype, and that excessive or deficiency specific elemental mineral stress had no significant effect., ９月から10月収穫の作型のキク（Chrysanthemum×morifolium）の葉身で発生する黄斑は水ストレス，高温，強日射，養分ストレスが発生要因として考えられている．本実験では無機養分の濃度，バランスが黄斑の発生に及ぼす影響を調査した．'精興の誠'を５種類の濃度の液肥（園試処方Ｎ０，60，120，180，240，300 ppm）で栽培した場合，液肥濃度が高くなるにつれ，黄斑が発生する範囲，程度共に増大する傾向が見られた．'精興の誠'と'精興の勝'に園試処方１/３濃度を基準とし，Ｎ，Ｐ，Ｋ，Ca，Mg，Fe それぞれを基準の３倍になるように作成した液肥を３または14日間与えた場合，'精興の勝'では黄斑発生は見られなかった．'精興の誠'では黄斑発生は見られたが，発生範囲，発生度ともに処理の影響は見られなかった．また，それぞれの無機養分を欠如させた液肥を作成し10日間与えた場合も黄斑発生に影響は見られなかった．これらの結果から，黄斑発生には遺伝的要因が関与しており，特定の無機養分の過不足により引き起こされるものではないと考えられた．