New directions in the handling of genome editing technology are being established worldwide, with cisgenesis and intragenesis attracting attention as promising technologies. These new approaches introduce target genes into target crops by transformation techniques, although the donor nucleic acids are limited to crossable species. These are excellent methods for introducing beneficial traits into crops with high polyploidy and long generation cycles. In this context, the European Food Safety Authority (EFSA) has compiled regulations for cisgenesis and intragenesis. Advancing their applications in Japan will require the establishment of social infrastructures for handling policies as well as public understanding.

Phenotyping is essential for crop breeding but is often time-consuming and labor-intensive, necessitating the improvement and efficiency. Hyperspectral (HS) imaging is a promising technology because it allows non-destructively analyze the internal state of plants and visualize the distribution of specific information. This study aimed to leverage this method to enable rapid and simple analysis of the chemical and physiological characteristics of plants. Specifically, we developed a non-destructive evaluation system for photosynthetic product contents in rice seedlings. Seedlings of the Japanese rice cultivar ‘Koshihikari’ and the Indian rice cultivar ‘IR64’ were grown under various light conditions, and HS reflectance data were extracted from images by an HS camera. After imaging, the rice seedlings were collected by parts, and the content of photosynthetic products (sucrose and starch) was determined by LC-MS analysis. Data from 198 leaf blades and 198 leaf sheaths were divided into training and validation datasets. Using HS reflectance data as explanatory variables and sucrose and starch content as response variables, we created a prediction model by partial least squares regression for each plant part and calculated the coefficients of determination (R²). Applying these prediction models for sucrose content (leaf blades: R² = 0.58, leaf sheaths: R² = 0.73) and starch content (leaf blades: R² = 0.89, leaf sheaths: R² = 0.68) to time-series HS reflectance data of the same plant allowed us to estimate the distribution of sucrose and starch content at the pixel level, visualizing their gradual increase under continuous light conditions. The measured values indicated an earlier increase in leaf blades followed by a delayed increase in leaf sheaths, this trend was also confirmed in the visualization images. These results suggest that HS imaging enables non-destructive visualization of differences and changes in photosynthetic product content at each part level in rice seedlings.

In recent years, foot rot caused by Diaporthe destruens has caused severe damage to sweetpotato in the Southern Kyushu area. In Japan, as foot rot was first observed in 2018, there is little information on foot rot resistance in varieties bred in Japan. In this study, 47 varieties (15 main and 32 reference varieties) were grown in a field infested with foot rot for two years (2020 and 2021), and evaluated for resistance to foot rot. The location and length of rotted parts of stems were measured from planting in early May to harvesting in early October, and the disease severity in vines, percentage of plants rotted at the basal part of a stem (PRS), and plant mortality were determined. After harvest, the percentage of storage roots with foot rot symptoms and the disease severity in storage roots were determined. Foot rot occurred about months after planting, and continued during the growth period, with significant differences in disease severity in the vines and PRS among main 15 varieties (P < 0.05). A high correlation was also observed between disease severity in vines and PRS, indicating that vine resistance can be evaluated using PRS as an indicator. Significant differences in disease severity in storage roots and percentage of storage roots with symptoms were also observed among varieties. Yields markedly varied among varieties, and were greatly affected by disease severity in vines. The degree of resistance of the 15 main varieties was evaluated based on the disease severity in vines and PRS on a five-point scale from ‘weak’ to ‘strong’ while also considering the disease severity in storage roots and yield. In addition, that of reference 32 varieties was evaluated based on PRS. As a result, ‘Daichinoyume’ was selected as ‘weak’, ‘Koukei No.14’ as ‘slightly weak’, ‘Ayamurasaki’ as ‘medium’, ‘Konaishin’ and ‘Benimasari’ as ‘slightly strong’, and ‘Tamaakane’ as ‘strong’ indicator varieties. These findings on resistance may contribute to future management of foot rot and the breeding of resistant varieties.

The first early-maturing Japanese durum wheat cultivar, ‘Setodure’, released in 2016, is grown in western Japan, where harvest precedes the seasonal rains in June. However, ‘Setodure’ has insufficient resistance to preharvest sprouting and Fusarium head blight, and lacks the desired yellowness and texture. The Western Region Agricultural Research Center, NARO, has bred a new durum wheat cultivar, ‘Setodure R5’, anticipated to be a successor to ‘Setodure’. Variety registration was applied for in 2023. ‘Setodure R5’ was bred by the derived line method from a Mv-Pennedur/Setodure//Setodure population. ‘Setodure R5’ has early maturity like ‘Setodure’, but with a 10% lower yield and a 1% higher seed protein content. Its resistance to preharvest sprouting and Fusarium head blight and its yellow pigment content are superior to those of ‘Setodure’. The higher pasta making quality with higher strength and preferable texture of the boiled pasta of ‘Setodure R5’ (with Glu-B1h and LMW-2) compared with ‘Setodure’ (with Glu-B1d and LMW-1) are associated with its glutenin composition.

In the southern part of Kyushu region, where about 40% of sweetpotato in Japan is produced, sweetpotato foot rot disease (foot rot disease) caused by Diaporthe destruens has done severe damage to sweetpotato production since 2018. Because the major cultivars for table use ‘Kokei No. 14’ and ‘Beniharuka’ are susceptible to this disease, new cultivars that can replace them are desired by farmers. ‘Benihinata’ is a new sweetpotato cultivar bred by NARO in 2023 for table use with strong resistance to this disease. From the 2 years’ experiments of the infested field by Diaporthe destruens, the foot rot resistance of ‘Benihinata’ was “strong”, which was much better than that of ‘Kokei No. 14’ (“moderately weak”) and that of ‘Beniharuka’ (“weak to moderately weak”). The other main characteristics of ‘Benihinata’ are as follows. The yield was higher than that of ‘Kokei No. 14’, but similar to that of ‘Beniharuka’ in standard and early production periods at the NARO Miyakonojo research station. The skin color of ‘Benihinata’ was “purple red” and the uniformity of storage root shape was “medium to moderately uniform”, and generally the appearance of the root was “medium to moderately good”. The steamed flesh color of ‘Benihinata’ was “light yellow white” which was lighter than those of ‘Kokei No. 14’ and ‘Beniharuka’. Using storage roots stored for 1 to 2 weeks after harvest, the brix value and texture of steamed roots were evaluated. The brix value of ‘Benihinata’ was higher than that of ‘Kokei No. 14’ and lower than that of ‘Beniharuka’. The texture of steamed storage root of ‘Benihinata’ was “medium” which was the same as ‘Kokei No. 14’ and ‘Beniharuka’. Even with a storage duration of three months, the texture of ‘Benihinata’ staid “medium”. This trait is clearly different from ‘Beniharuka’ with “moderately sticky” to “sticky” texture and is rather similar to ‘Kokei No. 14’. ‘Benihinata’ was evaluated in other fields in Miyazaki and Kagoshima prefectures from 2021 to 2023 which are target areas of its extension. The yields were 79% to 126% compared to ‘Kokei No. 14’. The texture of the storage root of ‘Benihinata’ was “powdery” to “moderately powdery”. From these results, ‘Benihinata’ is expected to mainly replace ‘Kokei No. 14’ and to contribute to stable sweetpotato production for table use in the southern part of the Kyushu region.

The bread wheat cultivars ‘Setokirara’ and ‘Minaminokaori’ are widely grown in western Japan. ‘Setokirara’ is high yielding, but its grain protein content tends to be low. With low resistance to preharvest sprouting, ‘Minaminokaori’ is susceptible to quality deterioration after rainfalls during harvest. The Western Region Agricultural Research Center, NARO, developed a new hard winter wheat cultivar, ‘Setonohohoemi’, with a higher grain protein content and better bread-making quality than ‘Setokirara’, and stronger resistance to preharvest sprouting than ‘Setokirara’ and ‘Minaminokaori’. In recent years, premature panicle development due to warm winters has increased the risk in early spring of frost damage of young panicles of wheat cultivars with winter habit types I and II, which do not require low temperatures to initiate panicles. ‘Setonohohoemi’ has winter habit type IV (requiring some exposure to low temperatures), so its risk of frost damage is low, because young panicles develop when the weather has warmed, after the cold exposure required for vernalization. With the major QTL QYm.naro-2D, ‘Setonohohoemi’ shows resistance to wheat yellow mosaic virus (WYMV), which has spread to new regions. Therefore, ‘Setonohohoemi’ is suitable for a wide area from the Kanto region to Kyushu in Japan, with relatively cold winters and the presence of WYMV.