III-4. Radiation Chemistry & Biology

RIKEN Accel. Prog. Rep. 55 (2022)

RIKEN Accel. Prog. Rep. 55 (2022)

Producing high brix content of the sweet potato Anno-Beni bymutation induced using ion-beam irradiation
T. Hashiguchi,∗1 K. Yamane,∗1 J. Nagai,∗1 K. Fujikawa,∗1 K. Ishii,∗2 Y. Hayashi,∗2 and T. Abe∗2Ion-beam irradiation eﬀectively induces plant mutations and is used for plant breeding.1) The sweet potato
cultivar Anno-Beni, which has a high sugar content,
is an important and exquisite product in the Tanegashima island area. There has been a high demandfor Anno-Beni with a high brix content that remains
stable. The dry-matter contents and brix contents inthe sweet potato are correlated.2) Therefore, by inducing mutations through ion-beam irradiation, lines withhigher dry-matter contents and higher brix contents
can be selected. In a previous report, we described 31lines selected from the population of the Anno-Beni
B1 line irradiated with a C-ion-beam.3) This report
describes the results of the continued selection.
In 2017, ﬁve lines with better growth and higher drymatter contents than those of the control were selectedfrom 31 lines.
In 2018, the ﬁve selected lines were cultured at theshoot apex to produce 20 lines. The 20 lines weregrown by vegetative propagation, and ﬁve individual
plants per line were cultivated in the ﬁeld. We selectedfour lines that grew better and had higher dry-matter
contents and higher brix contents (0.8–3.2 and 2.0–2.9,respectively) than the control (Table 1).
In 2019, the four lines were grown by vegetative
propagation, and 30 individual plants per line werecultivated in the ﬁeld. The four lines that grew better and had higher dry-matter contents and brix contents (2.4–4.1 and 1.1–2.4, respectively) than the control (Table 1).
The four lines had 22–35% lower yield contents
than the control. The shapes of the tuberous roots
were spindle to cylindrical for the control and No.36-2,
whereas it was long-spindle to cylindrical for No.19-1,No.19-4, and No.20-2 (Fig. 1).

Table 1. Dry-matter and brix contents of four mutant linesof sweet potato.

/LQHQDPH

12
1R
1R
1R
&RQWURO %

'RVH*\

0HDQRIGU\PDWWHUUDWLR0HDQRIEUL[ 0HDQRI\LHOG.JD&RQWUROUDWLRZDWHULQDUDWLR6XEVHTXHQWO\WKHLUEUL[FRQWHQWVZHUHPHDVXUHG

∗21) Control (upper), No.19-1(lower left end), No.19-4 (lower leftcenter), No.20-2 (lower right center), No.36-2 (lower right end).
2) Harvested on September 17, 2019 (planting period:132 days).

Table 2. Evaluation results of four mutant lines of sweet
potato.
/LQHQDPH'RVH*\12
1R
1R
1R
&RQWURO %



0HDQRIVZHHWQHVV
GD\VODWHU


0HDQRIIOHVK
FRORU0HDQRI
DURPD

PRQWK GD\V PRQWK GD\V
ODWHU
ODWHU
ODWHU
ODWHU






PRQWKODWHU


0HDQRIVWLFNLQHVV
GD\V PRQWK
ODWHU
ODWHU 7KHHYDOXDWLRQVFRUHVZHUHLQWKHRUGHURIIURPWKH
ORZHVWVFRUH  0HDQ RI  HYDOXDWLRQV DIWHU WKUHH GD\V DQG HYDOXDWLRQV DIWHU RQHPRQWK

The four lines were examined for taste survey after
three days and after one month of storage (Table 2).
The sweetness of the four lines was higher than that ofthe control after one month. The ﬂesh color of No.19-1,
No.20-2, and No.36-2 was lighter than that of the control after one month. The aroma of the four lines after
storage for one month were almost equal to that of thecontrol. The stickiness of No.19-1, No.19-4, and No.362 were equal to that of the control after storage for onemonth. The sweetness, ﬂesh color, aroma, and stickiness tended to increase after storage for one month.
By selecting the dry matter rate from ion-beam irradiated postgrowth, we were able to select lines with highbrix contents and a sweet taste.
References  7KH WXEHURXV URRWV RI WKH IRXU OLQHV ZHUH VWHDPHG DQG GLOXWHG ZLWK

∗1Fig. 1. Tuberous roots of the four lines and control.

Kagoshima Prefectural Institute for Agricultural Development (KIAD)
RIKEN Nishina Center- 170 -1) T. Abe et al., Breed. Res. 16, 67 (2014).
2) M. Ouchida, K. Ueno, Rep. Kyushu Br. Crop Sci. Soc.
Jpn. 80, 22 (2014).
3) T. Hashiguchi et al., RIKEN Accel. Prog. Rep. 53, 207(2019).

1