Identifying varieties of local figs in Miyagi Prefecture
Masaaki OSAKA, Takeru ITABASHI and Masato SHIBATA
In Miyagi Prefecture, figs have been produced since the Meiji era as medicinal plants. Today, they are cultivated throughout the entire prefecture for raw consumption or use in‘kanroni’ (food simmered in sweet syrup). However, the specific fig type was never identified, and they have been treated as ‘local varieties’ up until now. Thus, we established a method of identifying varieties of fig using SSR markers and identified local fig varieties based on the SSR marker and phenotypic traits. As a result, it was possible to discriminate 12 existing fig varieties by using 7 SSR markers. By using these discrimination methods, we identified the varieties of the figs cultivated in 14 places within Miyagi Prefecture and discovered that they were of the ‘Brunswick’ variety.
Stable Production Techniques for Italian Vegetable “Puntarella”
Mayumi YAMAMURA, Akitosh SAWASATO, Takeo SASAKI＊and Hiroko SATO**
This study aims to establish stable production techniques for growing “Puntarella” a crop rarely grown domestically in Japan. We examined a variety of topics, including cropping conditions, fertilizer application rates, variety characteristics, methods of raising seeds, planting density, effects of late planting, defoliation, seed production techniques, favorable strain creation, and tissue culture conditions.
- Cropping Conditions
In the suburban areas of Sendai, Miyagi, flower stems can be extracted regardless of the sowing timing. However, quality flower stalks that are marketable are harvested when sowing occurs between mid-July and mid -August in an unheated greenhouse environment. This results in a stalk weight of approximately 500g. The highest quality stalks are harvested when sowing happens at the end of July. In open-field cultivation, early July to mid-July sowing allow for increased stalk harvest rates, but stem weight then ranges from 200 to 280g. Open-field stalks are thus lighter and of different quality than those from greenhouse cultivation.
Occurrences of disease-carrying insects are few, but countermeasures against cutworms are necessary for August sowing. Greenhouse management is also necessary to maintain warmth during the coldest seasons.
- Appropriate Fertilizer Application Rates
Increasing the fertilizer amount tends to result in an earlier harvest peak and a lighter average stalk weight. When considering yield/quality per a, an amount of 1.5kg/a of nitrogen is ideal for the base fertilizer.
- Variety Characteristics
Each of the 3 varieties tested has its own characteristics. “Gaeta” and “Garriana” have high year-end harvest rates, with average adjusted stock weights of just under 800g. They are early to mid-season cultivars with green flower stalks and are less thick than those of the “late cultivar species (name of third variety).”They are also strong against cold weather. The “late cultivar species” has a smaller year-end harvest rate, but the flower stem is white and thick and the average adjusted weight exceeds 1kg. It is of high quality but tends to be weak in the cold. All three cultivars have promising traits and have high harvest rates, so it is necessary to take the timing of the haversting period and quality into consideration when deciding on a variety.
- Seedling Raising Method
When raising seedlings at high temperatures, both “late cultivar species”and “Gaeta (to be referred to as‘early cultivar species’)” of “Puntarella” have high germination rates, improved initial growth, increased product yield and marketability percentages when seedlings are raised outdoors (tunnels with anti-insect nets). “Early cultivar species” also has a late sowing period and a flower bud differentiation timing later than that of “late cultivar species.”However, its harvesting period is earlier because of the wide temperature range in which bolting can occur after differentiation (easy to stretch even at low temperatures).
- Planting Pattern
In two-row planting of the tillering “late cultivar species” a spacing of 30 to 40cm (313 to 417 stocks/a) between plants is ideal when considering yield and quality. For the moderate tillering “early cultivar species” the preferable spacing is 25 to 30cm (417 to 500 stocks/a).
- Effects of Late Sowing on Growth and Yield
For the early cultivar species“ Gaeta,” a later standard sowing period results in later flower bud differentiation and harvesting, which reduces yield. Therefore, it is optimal for the sowing period to occur in early August.
“Late cultivar species” has a high yield, with a sowing season beginning in Late July followed by a harvesting season from November to the following March (harvesting every month is possible) being most ideal. If the sowing period is delayed, flower bud differentiation timing and bolting timing will also be delayed, leading to a decrease in yield.
- Influences of Defoliation
Defoliation done just once in December decreases insect pest occurrences while having minimal impact on overall yield, and even increases the current year's end yield. As such, early on in the harvesting period in early December, it is ideal to remove yellowed and unnecessary leaves one time and dry out the sliced areas after cutting by the end of that day.
- Establishment of Seed Harvesting Technique
Pollination for seed harvesting is best done under the conditions of clear weather, temperatures ranging from 25 to 35℃, and an illuminance of 10,000lx or above. The cultivation period is best held in spring, because while the cross-fertilization period is long the fruiting rate is high. Seed harvesting is then possible by both artifical crossing as well as natural outdoor crossing (flower-attracted insects). Seed harvesting for both varieties (“late cultivar species” and “early cultivar species”) is also possible.
For hybridizing selected favorable strains, an effective labor-saving seed production method is to first select strains suitable for selection during the harvesting period, grow those selected strains until the next spring, then once grown, transplant them to either outdoor or greenhouse environments to undergo artificial or natural crossing.
- Creating Favorable Strains
The intercross of selected favorable strains that prioritized the quality of “late cultivar species”saw trends of stock enlargement as well as a later harvesting period. In response to high demand and the need to raise harvest rates, hybridization of similarly annually harvested plants resulted in an increased year-end harvest, and little variation in the harvesting period timing. Additionally, it was also possible to increase the year-end yield by crossing “early cultivar species,” which has a high year-end harvest ratio, with “late cultivar species.”
Among tissue culture samples of favorable strains it was confirmed that there was an increase in the percentage of high quality samples, with less variation in quality overall. If these culture samples were to be crossed as parents, new strains of more uniform quality may be obtained.
Additionally, when considering crossing combinations, the selection of the mother plant is important because maternally inherited traits become dominant after crossing.
- Tissue Culture Conditions for Maintaining Favorable Strains
As callus induction and redifferentiation medium, MS medium + NAA 5.0 mg / l + BA 0.1 mg / l was used, and by using flower peduncle parts, many redifferentiated bodies were obtained. 1/2 MS medium + 0.1 mg / l IAA (before autoclave addition) is also suitable as rooting medium.
It was found from observing the growth stages of subcultures that approximately 40 days is the appropriate length for the primary tissue culture period in callus induction and redifferentiation medium.
Effects of UV-B Radiation Combined with Reflective Plastic Mulch on Tetranychus Urticae in Strawberry Production
Kafuka SUZUKI,Takayuki SEKINE,Atsushi OHBA and Shiori TAKAYAMA
Ultraviolet-B (UV-B) radiation is used as a countermeasure against powdery mildew on strawberries. In this study, the effects of UV-B radiation exposure as a measure for controlling Tetranychus urticae were tested. After conducting tests using the leaf disk method in strawberry production, it was observed that the UV-B radiation caused adult females to lay fewer eggs than normal and prevented some of the eggs from hatching, thus confirming the effects of UV-B radiation exposure in controlling T. urticae. Upon conducting tests that combined the use of Phytoseiulus persimilis and UV-B radiation in soil cultivation, we concluded that reflective plastic mulch, which can reflect UV-B radiation to the undersides of leaves, effectively suppressed the number of T. urticae. The P. persimilis further suppressed the number of T. urticae by feeding on them. Another UV-B radiation test utilizing Amblyseis californicus found in elevated cultivation showed that the combination of A. californicus, which feeds on T. urticae, and reflective plastic mulch was also effective in suppressing the number of T. urticae.