At the Agricultural Experiment Station of the Akita Prefectural Agriculture, Forestry and Fisheries Technology Center, with the goal of producing large ball watermelons with red flesh suitable for normal open field cultivation, commercial F1 breeds are combined with progeny fixed lines. In watermelons, the mating direction (forward and reverse) is a characteristic of F1 The general idea is that it has nothing to do with the 15 breeding lines, and (15 × 14) / 2 = 105 different F1s could be created by simply combining them, but it seems that they were breeding from the same material variety. Do not combine strains, strains with soft flesh As a result of considerations such as not combining lines with each other, avoiding lines without bloom (waxy substance on the surface of the fruit), and combining with black seed color (black is dominant), the 2000 Fall / Winter crop yields 20 F1 mix seeds. From 2001, it seems that the characteristics of the breeding F1 lines and the narrowing down of promising lines were conducted. In 2001, a total of 20 strains bred were compared in open-field ordinary cultivation in an agricultural test field, and among them, four strains (‘Autumn Test Exchange No. 4’, ‘Ex. In addition, the characteristics survey was also conducted in the open field normal cultivation of the field test, and ‘Autumn test exchange No. 4’ and ‘Dokyo No. 5’ were recognized as promising from the variety of fruits and taste. In 2002, we added tunnel mobile cultivation to the field test, and in 2003, we recognized ‘Autumn Test Exchange No. 5 Watermelon’ as the most promising, judged it to be superior to existing varieties, and started breeding. completion. In April 2004, we applied for the cultivar registration under the cultivar name ‘Akita Natsubiyori (Natsubiyori Watermelon)’, which was decided by public offering, Received an order to change the middle name, and the runner-up, ‘Akita Natsumaru watermelon’ In October 2004, the application was published. The variety was registered in March 2007 (No. 15135) after a field survey of the applied variety in July 2005. The characteristics of the parent line of the F1 variety ‘Akita Natsumaru Watermelon’ are that the mother ‘H09sTI-2’ is a fixed progeny of ‘Koryoku watermelon’ (Villemorin Mikado Co., Ltd.) and has strong grass, slightly large leaves, and slightly large fruits. The fruit is small, but has a dark green color, a high sugar content, and a dark flesh color. The fruit surface is slightly grooved, the bloom is very dark at maturity, and the seeds are black. On the other hand, ‘H09sIW-1’ of the father is ‘Tsuru no Izumi Watermelon’ (bred by Iwakura Seed Store (Nishiwaki, Suruga Ward, Shizuoka City, Shizuoka Prefecture)), which is progeny-fixed. It has excellent cultivating characteristics such as large and well-arranged seeds.It seems that this line has no bloom on the pericarp and black-brown seeds. In addition, both parents seem to have a strong sense of sharpness. F1 ‘Akita Natsumaru Watermelon’ has quantitative traits such as elongation, grass Vigor Leaf size Fruit size Pericarp color Thickness of streaks, sugar content, flesh color (darkness of redness), flesh hardness, etc. are almost intermediate between the parents, and expressed dominantly in qualitative traits. A strong bloom occurs on the fruit surface, and the seed color seems to be black. H09sTI-2( ) H09sIW-1( ) ♀ ♂
Yokote City is famous for being the number one producer of watermelons in Akita Prefecture. The city is located in the Yokote Basin, surrounded by mountains to the east and west, and is said to be suitable for growing watermelons due to the large temperature difference between day and night. In the city, there is a tendency to cultivate mainly the “Akita Natsumaru Watermelon” series, which is an original variety of Akita Prefecture. This excellent range of produce is characterized by its crispy texture and sweet taste. By the way, it seems that July 20th is Akita Natsumaru Day because it means 7 (7), 2 (2), and 0 (0).
It seems that the following three policies were set at the beginning of Akita Prefecture’s breeding goals. First of all, he emphasized the dissemination of the results, and rather than watermelons with special characteristics, it seems that he targeted the types that are the most popular in this prefecture today, such as large ball, spherical shape, striped skin, and red meat. No. Secondly, in order to cultivate varieties that are easy to cultivate and adapted to the weather conditions of this prefecture, it seems that they decided to carry out breeding selection within the prefecture. Thirdly, F1 varieties that are well-matched, can accumulate many excellent traits, and can compete with the varieties developed by private seed manufacturers. It seems that it was decided to nurture it. Open-field ordinary cultivation, which is the main cropping type in Akita Prefecture, is a sparse planting that produces fruits per stump. Since a large number is required, the ball must be well-matched and the rate of excellent products must be high. In recent years, cut sales have become mainstream due to the progress of nuclear families, so hollow fruits are less likely to occur, and the flesh color is bright. Due to changes in consumer tastes, it should be hard, chewy, and have a high sugar content. It is to have originality that can be differentiated from other production areas. In addition, since there were no native watermelon species in Akita Prefecture, breeding began with the introduction of materials. At that time, the main cultivars in the prefecture were ‘Hissho Watermelon’ (developed by Yamato Farm) with high yield in open field cultivation, and Kansen Watermelon (marutane seedling cultivation) with high sugar content in regular pruning cultivation. On the other hand, it seems that there was also a problem with cultivation. In other words, ‘Hissho Watermelon’ is easy to crack, and the pulp is moist here and there. . During the five years from 1994 to 1998, he introduced F1 55 breeds of large red meat balls on the market and investigated their characteristics. For the introduction, not only varieties that are popular in the prefecture, but varieties from all over the country were collected to search for materials.From the results of the characteristic survey, 13 F1 varieties were considered promising as breeding materials. The first F2 separation was started in 1995, and since then F2 separation has progressed as needed, and by 2000, the fixation has been completed in the F5 generation and above. Among the 13 varieties used as breeding materials, some strains were discontinued in the middle of selection, and it seems that 15 strains were finally obtained from 8 varieties. For these lines, the excellent characteristics retained by the F1 parent cultivar are maintained almost unchanged. It seems that I was able to Generation promotion was carried out by ground cultivation with 40 cm spacing between each plant and one fruit. In addition, it seems that trial mating combinations were performed from the F4 generation onwards. The reason why the number of F2 isolated generations is around 15 strains is that preliminary tests revealed that the progeny of the large ball cultivar on the market has a relatively narrow range of mutation, so we concentrated on a small number of cultivars. Rather than tackling systematically, many cultivar progeny should be broadly and shallowly dealt with. It seems that it was determined that it was more efficient to get it.