The Japanese Society for Horticultural Science
Acta Medica Okayama
21890102
89
2
2020
Propagation and Floral Induction of Transplant for Forcing Long-term Production of Seasonal Flowering Strawberries in Japan
87
95
EN
Yuichi
Yoshida
Graduate School of Environmental and Life Science, Okayama University
Toshi
Nishimoto
Nara Prefecture Agricultural Research and Development Center
In Japan, over 95% of the acreage is covered with plastic to force June-bearing (seasonal flowering, SF) strawberry cultivars to produce fruit from late fall to early summer. During the late 1960s, a forcing technique was developed that advanced flower bud initiation to late summer and prevented the transplants from becoming dormant during winter. This new forcing technique involved nitrogen starvation of nursery plants to induce floral initiation. Until about 1980, strawberry growers in Japan used runner plants produced in waiting beds, but most transplants are now produced in plastic pots under rain shelters to avoid soil-borne diseases. Recently, the use of tray plants produced from hanging runner cuttings has become popular. To induce early floral initiation, the following artificial low temperature (LT) treatments have been established: (1) “Yarei”, a combination of a short day with solar radiation and LT under darkness in cooling facilities (Yarei-ko); (2) “Kaburei”, continuous dark-LT with refrigeration facilities including industrial warehouses; and (3) “Kanketsu-reizo”, intermittent LT storage. An overview of the technologies applied to plant propagation and the control of floral initiation of Japanese SF cultivars is provided in this review.
No potential conflict of interest relevant to this article was reported.
The Japanese Society for Horticultural Science
Acta Medica Okayama
21890102
89
1
2020
Effect of Defoliation on Blossom-end Rot Incidence and Calcium Transport into Fruit of Tomato Cultivars Under Moderate Water Stress
22
29
EN
Annah Khatenje
Indeche
Graduate School of Environmental and Life Science, Okayama University
Yuichi
Yoshida
Graduate School of Environmental and Life Science, Okayama University
Tanjuro
Goto
Graduate School of Environmental and Life Science, Okayama University
Ken-ichiro
Yasuba
Graduate School of Environmental and Life Science, Okayama University
Yoshiyuki
Tanaka
Graduate School of Environmental and Life Science, Okayama University
The translocation of calcium (Ca) within the tomato plant and the causes of Ca deficiency, a factor associated with blossom-end rot (BER) in fruit, are still a matter of conjecture. The objective of this study was to determine the effect of defoliation on BER incidence and Ca transport into different size tomato fruit cultivars. Four experiments were conducted. The start and end dates for each experiment were; 14 March–2 May, 22 July–23 August, 30 August–7 October 2017, and 20 May–25 June 2018, for experiments 1, 2, 3, and 4, respectively. Five tomato cultivars including one large (‘Momotaro fight (MF)’, ≥ 200 g), three medium (‘Lui 60 (L60)’, ‘Tio cook (TC)’, and ‘Cindy sweet (CS)’, 30–80 g), and one small (‘Pepe (PP)’, ≤ 20 g) fruit cultivars, respectively, were grown under moderate water stress controlled by a combination of root zone restriction and solar mediated fertigation. Leaf area of plants was reduced by 20–30% by removing alternate leaflets on all leaves. Defoliation significantly reduced BER in all experiments. In experiment 4, no BER was observed in defoliated plants of L60 and PP, and in MF and TC, BER incidence decreased to a quarter of the control. Defoliation increased the fruit growth rate (FGR) in experiment 1, in which the temperature was the lowest, by a ratio of 1.42 and by 1.39 in experiment 4, in which the radiation was strongest and day length longest. Defoliation increased the rate of daily Ca transport into fruit (CTR) in MF, L60, TC, CS, and PP by average ratios of 1.64, 1.55, 1.35, 1.30, and 1.13, respectively. The increase in CTR in defoliated plants was highest in experiment 4 with a ratio of 1.68 followed by 1.37, 1.33, and 1.28 in experiments 1, 3, and 2, respectively. Defoliation increased both FGR and CTR and there were significant linear relationships between them. However, the degree of increase was larger in CTR than that in FGR, especially in the BER-sensitive large fruit cultivar MF, and defoliation increased the total Ca concentration in fruit accordingly. We conclude that under moderate water stress by root zone restriction and certain other BER inductive conditions, defoliation could be a promising approach to reduce BER incidence by improving Ca nutrition in susceptible large fruit cultivars.
No potential conflict of interest relevant to this article was reported.