‘Melon Chukanbohon Nou 5 Go’, a melon parental line with resistance to Cucurbit chlorotic yellows virus (CCYV), was developed from a cross between the CCYV-resistant I-10 and the CCYV-susceptible ‘Earl’s Favorite Harukei No. 3’. ‘Melon Chukanbohon Nou 5 Go’ presents milder symptoms than susceptible cultivars. This resistance is controlled by one recessive gene. The simple sequence repeat (SSR) marker ECM230 on chromosome 1 was selected and this marker can be used for selection in CCYV-resistance breeding in melon. The internode and petiole lengths of ‘Melon Chukanbohon Nou 5 Go’ are longer than those of ‘Earl’s Favorite Harukei No. 3’. The fruit shape is oblate and the fruit matures approximately 45 days after fl owering. The fruit contains grooves and a pistil scar is larger than that of ‘Earl’s Favorite Harukei No. 3’. The strength of the peduncle attachment is weak, and the Brix value of fl esh is approximately 11°.

The effect of the optimal timing for the spraying of the diamide insecticides, flubendiamide or chlorantraniliprole, for the suppression of the first- or second-generation larvae of the persimmon fruit moth, Stathmopoda masinissa Meyrick, on the suppression of the persimmon bark borer, Euzophera batangensis Caradja was investigated in a persimmon orchard. Fruit damage caused by the fi rst- or second- generation larvae of S. masinissa in trees that were sprayed with diamide insecticides was as low as that in control trees. There were fewer larvae of the overwintering generation of E. batangensis on persimmon branches or twigs of trees sprayed with diamide insecticides at the optimal time for suppression of the second-generation larvae of S. masinissa than on the control trees. The number of second-generation larvae of E. batangensis on persimmon branches or twigs of trees sprayed with diamide insecticides at the optimal time for suppression of the fi rst-generation larvae of S. masinissa was as low as those on control trees. The density of the overwintering generation of E. batangensis was high, and this generation was effectively suppressed by diamide insecticides spraying; however the density of second-generation larvae of this pest was low and was considered not to require suppression by diamide insecticide spraying. Therefore, we have recommended the optimal timing of diamide insecticides spraying for the suppression of second-generation larvae of S. masinissa to control the overwintering generation of E. batangensis.

“Harunoogi” is a new sugarcane cultivar jointly developed by the NARO Kyushu Okinawa Agricultural Research Center and the Japan International Research Center for Agricultural Sciences. It shows vigorous initial growth after ratooning and high ratoon yield in the Kumage region in the Kagoshima Prefecture, and has been applied for variety registration for the region in March 2019. “Harunoogi” was selected from progenies derived from crossing between a high ratoon yield forage cultivar “KRFo93-1” as seed parent and a thick-stalk early maturing cultivar “NiN24” as pollen parent. The “KRFo93-1” was developed by interspecifi c hybridization of a commercial sugarcane cultivar with a wild sugarcane (Saccharum spontaneum L.). Ratooning ability and number of tillers of “Harunoogi” are higher than those of “NiF8”, which is a major cultivar in the Kumage region. Even though single stalk weight of “Harunoogi” is smaller than “NiF8”, stalk yield is much higher compared to “NiF8” due to its large number of millable stalks in both plant and ratoon crops. Sucrose content of “Harunoogi” is comparable with “NiF8”. As a result, sugar yield of “Harunoogi” is much higher than “NiF8”. In addition, “Harunoogi” has good adaptability for mechanical harvesting because of its high lodging-resistance and vigorous initial growth in ratoon crop after mechanical harvesting. High ratoon yield under mechanical harvesting system has been recognized as one of the most important characteristics of sugarcane cultivar in the Kumage region where ratoon yield has been decreasing for recent years. “Harunoogi” is expected to play an important role in recovery from a decline of sugarcane yield in the region.

The supply of squash (Cucurbita maxima Duchesne ex Lam.) in Japan mostly depends on overseas imports from winter to spring. Cultivars with a high degree of storability are needed for the off-crop season in Japan. Since there has been little physiological analysis of the fruit with focus on varietal differences in storability, we analyzed the sugar metabolism of squash fruit during storage to establish selection indicators of storability. Squash cultivars with different degrees of storability were cultivated in Sapporo in 3 seasons (2016-18), and fruits were stored at 10 °C. Starch contents of ‘Hakushaku’ and ‘Oitokekuritan’, which are regarded as cultivars with superior storability, were higher than those of other cultivars. The rates of dry matter of the cultivars were ranked in the order of starch contents of the cultivars and were highly correlated with the total values of starch and soluble sugar contents. A decrease in starch content and an increase in soluble sugar content were observed in all of the cultivars except ‘Colinky’ during storage. The contents of sucrose in ‘Hakushaku’ and ‘Oitokekuritan’ rapidly increased during the fi rst 30 days of storage and became higher than those of other cultivars during storage. The contents of glucose in those two cultivars were lower than those in ‘Ebisu’ during storage. Similar results were obtained for ‘Yukigesho’, which showed a high starch content in 2018. Before storage, the glucose contents and total soluble sugar contents in ‘Hakushaku’, ‘Oitokekuritan’ and ‘Yukigesho’ were low.

Suzumaru R was developed by introducing three resistant genes against soybean cyst nematode, namely, rhg1, rhg2, and Rhg4 into Suzumaru by backcrossing six times and marker-assisted selection. In the present study, we performed whole genome re sequencing of the soybean varieties Suzumaru and Suzumaru R and compared the sequence for isogeneity confi rmation of the genetic backgrounds of the varieties. At the genome level, Suzumaru and Suzumaru R were found to have the same genetic background, using a sliding window analysis, except for three fragments, each of which contained rhg1, rhg2, or Rhg4, and a 3.6-Mb fragment at the end of chromosome 5. In the breeding process, the end of chromosome 5 was intentionally selected for soybean dwarf virus resistance (Rsdv1) from the donor parent in the BC₆F₁ to BC₆F₄ generation. However, plants having Rsdv1 showed unfavorable traits, and therefore, plants that did not have Rsdv1 were selected eventually. This small fragment on chromosome 5 might be a remnant region. Thus, whole-genome re-sequencing can be a powerful tool for in-depth analyses of the difference between two varieties. Applying this technology to backcross breeding would enable “precision breeding.”