- 著者
- Fumie Nishikawa Mitsunori Iwasaki Hiroshi Fukamachi Tomoko Endo
- 出版者
- 一般社団法人 園芸学会
- 雑誌
- The Horticulture Journal (ISSN:21890102)
- 巻号頁・発行日
- pp.OKD-031, (Released:2016-11-29)
- 被引用文献数
- 8
In citrus trees, a technique for predicting the number of flowers is needed to prevent inconsistent fruit production over time. In this study, we investigated whether a flowering-related gene, citrus FLOWERING LOCUS T (CiFT), can be used to predict floral production. We quantified CiFT expression levels in stems of Satsuma mandarin (Citrus unshiu Marc.) trees planted at two remote locations. We collected samples over 3 years, and determined that the CiFT mRNA levels in November were strongly correlated with the number of flowers produced the following spring. The correlation between CiFT expression and floral production exhibited almost no differences among years or between sample collection sites. Thus, the CiFT expression level in November can be used to predict the number of flowers the following spring, and this prediction method can be used at different locations and over several years. To verify the practical utility of this method, Satsuma mandarin shoots were transported in November from eight locations across Japan to our laboratory under cool conditions. Transport times were approximately 4–72 h, and samples were immediately frozen upon arrival. The CiFT expression levels in transported stems correlated with the number of flowers in the following spring. Additionally, those correlations were similar in transported samples and samples that were frozen immediately after collection. Our results suggest that the number of flowers can be predicted even with the CiFT expression levels quantified in transported samples.
- 著者
- Mitsunori Iwasaki Fumie Nishikawa Hiroshi Fukamachi
- 出版者
- The Japanese Society for Horticultural Science
- 雑誌
- The Horticulture Journal (ISSN:21890102)
- 巻号頁・発行日
- pp.UTD-017, (Released:2018-12-07)
- 被引用文献数
- 3
Sheet-mulching cultivation during the fruit developmental stage is often carried out to produce high-quality Satsuma mandarin (Citrus unshiu Marc.) and ‘Harehime’ ((‘Kiyomi’ × ‘Osceola’) × ‘Miyagawa-wase’) fruits because they show high Brix% by exposure to drought stress conditions. In this study, we investigated the effect of drought stress on the number of floral buds in ‘Haraguchi-wase’ Satsuma mandarins and ‘Harehime.’ To clarify the relationship between drought stress and the number of floral buds, we applied four different drying treatments to the fruit trees, (i) first-half drying (drying treatment during the first-half of the fruit development stage), (ii) second-half drying (drying treatment during the second-half of the fruit development stage), (iii) all-drying (drying during the full fruit development stage), and (iv) well-watered (non-drought stress during the fruit development stage). The drying treatment was applied to the fruits at ψ max −0.7 to −1.2 MPa at an intensity comparable to proper drought stress for high-quality fruit production according to our previous studies. In ‘Haraguchi-wase,’ the all-drying treatment produced a higher number of floral buds in the following spring season compared with the well-watered treatment, in which the increase in the number of floral buds took place concomitant with the enhancement of CiFT expression in December. As expected, the fruits after all-drying were smaller with a significantly higher Brix% and a similar level of citric acid content, suggesting that drought stress of suitable intensity resulted not only in high-quality fruit production, but also in an increased number of floral buds in the following spring season. The results also demonstrated that the first-half drying caused higher CiFT expression and more inflorescences than in the well-watered plants, while there were no differences in CiFT expression or number of floral buds between the second-half drying and well-watered treatments. These tendencies observed in ‘Haraguchi-wase’ were the same as in ‘Harehime.’ Therefore, the drying treatment during the first-half of fruit development could be an effective method to increase the number of floral buds.