The research and academic facilities of Hokkaido University extend to Hokkaido and Wakayama Prefecture, including experimental farms and a breeding farm, extensive research forests, training ships and aquatic research stations. With a total area of approximately 70,000 hectares, the experimental forests are among the largest in the world. The “Fields of Knowledge” series focuses on the various research and academic activities that take place in the fields.
Hokkaido University has experimental farms in Sapporo and Yoichi City. Yoichi Orchard, located in Yoichi City, about 60 km from Sapporo, belongs to the Experimental Farms. The orchard was established in 1912 for the research and promotion of fruit growing in this relatively warm region of Hokkaido, which is suitable for fruit growing.
Practical orchard training
In mid-September, students practice in Yoichi’s orchard in the middle of the harvest season. Under the guidance of Professor Yoichiro Hoshino (Field Science Center for Northern Biosphere) and technical staff Minoru Ikuta (Field Science Center for Northern Biosphere), who manages the orchard, students learn about harvesting apples from trees and sorting fruit before shipment.
Skillfully students harvesting apples
Sorting harvested apples into standardized and non-standardized products
Ikuta has worked at the orchard since he was 20 years old and usually sprays chemicals and prunes the fruit trees. “I’m delighted to see the students enjoy their work during the training,” he says.
Minoru Ikuta explains how to harvest apples.
Cutting-edge research at the orchard
Yoichi Orchard grows about 60 varieties of fruit crops. They are used not only for the practical training of students, but also for advanced research. Professor Hoshino promoted breeding using plant genetic resources of Hokkaido, and orchard fruit trees are used for this research. In particular, he focuses on haskap, which grows abundantly in Hokkaido, and works to develop more delicious berries. He has conducted various experiments, such as crossing haskap with other berries, and is particularly focused on research using a method called “polyploid selection”, in which the number of chromosomes is manipulated.
Professor Hoshino speaks in front of an apple tree
Ploidy is a concept that indicates the number of sets of chromosomes that an organism has. Most animals are diploid, having two sets of chromosomes, one set coming from their parents. Plants, on the other hand, have a variety of ploidy. In nature, there are not only diploids but also tetraploids, each of which has four pairs of chromosomes. Therefore, by crossing plants of different ploidy, it is possible to produce new ploidy variants not found in wild species. For example, by crossing a diploid watermelon with a tetraploid, a triploid watermelon can be produced, also known as a seedless watermelon. Polyploidy breeding also attracts attention as flowers and fruits become larger as ploidy increases.
Haskap grown by Professor Hoshino
However, there are various problems in breeding ploidy, such as poor growth after fertilization and the time taken to bear fruit. Professor Hoshino tried to solve these problems by using the “endosperm” inside the seed. Endosperm is a special tissue with 1.5 times more chromosomes than other tissues: i.e. triploid endosperm in diploid plants and hexaploid in tetraploid plants. Professor Hoshino succeeded in producing a plant directly from the endosperm by taking only the endosperm from a seed and cultivating it. When the number of chromosomes was examined, it was found to maintain a ploidy of 1.5 times, just like in the endosperm. In other words, this method allowed the creation of new polyploid variants faster and more reliably than existing methods. This method developed by Professor Hoshino is called endosperm culture.
Haskap is grown not only in Yoichi’s orchard, but also on the farm at the Sapporo campus.
Professor Hoshino says Yoichi’s Orchard is indispensable for such research. Yoichi Orchard, which has a history of over 100 years, cultivates and maintains a wide variety of plant and tree cultivars. Normally, if you wanted to research apples, for example, it would take years to grow them from seed. But since Yoichi Orchard maintains so many varieties here, one can immediately try any idea that comes to mind. It is therefore a very attractive environment for researchers. It also allows researchers to pick even immature fruit trees for their research, and is still very flexible.
With students from the Hoshino Laboratory. Right: Jung Tae Kim (3rd year PhD student, Graduate School of Environmental Sciences), Center: Haruna Suzuki (1st year Masters student, Graduate School of Environmental Sciences). The video also features Kim and Suzuki’s research.
Yoichi Orchard is an important asset of Hokkaido University where students can experience the joy of growing fruit trees and where researchers can come into contact with a valuable resource. New, world-class technologies will continue to be created here at Yoichi Orchard.
Originally written in Japanese by Yu Kikuchi.
Translated by Sohail Keegan Pinto