Collaboration for Agriculture and Rural Development
(CARD)
Program
288
RESULTS OF AN EVALUATION AND SELECTION OF
NEW SWEET POTATO VARIETIES IN BAC GIANG, THANH HOA
AND QUANG TRI PROVINCES
Project title:
Selection and development sweet potato varieties with high root quality for food
processing in Northern and Central of
Vietnam
Code of the project
: CARD 008/07 VIE
Author(s):
Nguyen Van Tuat
1
, Truong Cong Tuyen
1
, Nguyen Dat Thoai
1
, Truong Thi Thuy
1
, Tran
Quoc Anh
1
, Nguyen Phan Anh
1
, Do Thi Lieu
1
, Nguyen Thi Hoai
1

ssistance of Australian experts, improve the science capacity of Vietnamese
researchers and extension workers in modern techniques for plant improvement, storage and food
processing technology, analysis of food quality; 5) Improve farmer’s knowledge and sk
ills in
cultivation of sweet potato as a part of a sustainable farming system and 6) Establish model sites to
display advanced cultivation techniques, and organize field day meetings to disseminate knowledge to
farmers.
The project has been conducted in tw
o years 2008
-
2009 and this report reflects the results of those
activities in project sites that have been reviewed and discussed at the project completion meeting and
the Public Forum in April 2009.
The results of field trial and evaluating new sweet pota
to varieties in Thanh Hoa, Quang Tri and Bac
Giang provinces have indicated that among 11 varieties it has been chosen 3 good ones including
VC68
-
2, VC 02
-
193 and VC 04
-
24 with the yield ranged from 13.64 to 23.6 tonnes/ha, compared to
check control yielde
d 10.13 to 14.9 tone/ha
1.
Introduction
The cultivation area of sweet potato in
Vietnam annually ranging 200,000
-

demand of starch for industry in Vietnam
annua
lly is about one million tons, much of
which is imported. The lack of good
cultivars and relevant technology for
cultivation and processing of sweet potato
means that this crop is not achieving its
great potential for contributing to
increasing income and
providing
socioeconomic benefits for farmers in
poorer regions. At FCRI, several sweet
potato cultivars, such as sweet potato No.8,
KB1, KL5, K4, K51, Advance 1, Advance
2 and Hoang Long, have been identified
for their agronomic and adaptive traits,
resist
ance to key insect pests and diseases,
and nutrient requirements. However, these
cultivars have not been evaluated for yield
and dry matter production and
performance in processing. The central
region and some northern provinces of
Vietnam have suitable gr
owing seasons for
tuber crops. The cultivation of sweet
potato crops in these regions needs to be
investigated as part of a sustainable
cropping system that increases farmer
income. In this paper the research results

Yen, Ngoc Chau
-
Tan Yen, Mai Trung
-
Hiep Hoa)
-
Thanh Hoa province (Nguyên
Binh
-
Tinh
Gia, Quang Luu
-
Quang Xuong, Dong
Thanh
-
Dong Son)
-
Quang Tri province (Vinh Thai
-
Vinh
Linh, Gio Hai
-
Gio Linh, Hai Quy
-
Hai
Lang)
2.3
Research content
-
Evaluate and select new potato varieties


Planting method
-
Cut and plant sweet potato root with
the clean
tools in all of the locations.
-
Distance: the distance between two
plants in a row was 0.2 m and the
density was 40,000 plants/ha
-
Align the plant vertically to the bed
surface

Planting time:
-
Thanh Hoa and Bac Giang: 5
-
10th
October
-
Quang
Tri:
15
-
20th Dece
mber
NV
Tuat,
TC Tuyen

Cattle manure
15,000
-
Urea
150
60
-
70 kg N/ha
Super
Phosphate
550
90
-
100
kg
P/ha
Kali
220
120 kg K/ha
-
Mix all of the cattle manure and super
phosphate as well as 30% of urea and
30% of
potassium for treatment
before planting.
-
Half of the remaining Urea and Kali
fertilizers were fertilized 20
-
25 days

Evaluate and select new potato
varieties in Bac Gia
ng and Thanh Hoa
based on quality and yield
The dry matter contents were determined for
roots of the sweet potato varieties at all of
locations in Bac Giang and Thanh Hoa, 2008
(Table 1). The highest dry matter content in
these sweet potato varieties were
25.65% of
HT2 and 25.38% of VC01. The values were
much higher than those of Hoang Long
(21.29%) and the local (20.49%). On the other
hand, in the same varieties, the dry matter
content in a location was different between
locations. For example, HT2 had hig
h dry
matter content of 33.5% and 30.73% in S2 and
S6, respectively but only 24.6% and 18.57% in
S1 and S3, respectively. Therefore, varieties
and environment caused different dry matter
content of these sweet potato roots. The main
factor was the winter
in Bac Giang (S1) and
Thanh Hoa (S3) influencing unfavourably dry
matter content.
Table 1:
Dry matter content (%) in root of Sweet potato varieties in Winter season
2008
Sites

19.50
21.23
23.83
22.47
23.05
HT2
24.6
33.50
18.57
21.37
25.10
30.73
25.65
TM1
22.5
23.70
19.07
20.87
18.67
18.20
20.50
VC.01
27.53
29.10
19.13
23.00
27.13
26.40
25.38
VC.68

20.90
20.81
VC02
-
193
20.13
28.63
18.83
21.93
20.87
18.80
21.53
Hoang Long
21.57
24.47
18.17
22.87
21.77
18.90
21.29
Local variety
20.23
21.73
19.20
19.83
20.73
21.23
20.49
Mean
22.22

-
Evaluation of root yield
:
Root yield
of the
new sweet potato varieties in Thanh Hoa and
Bac Giang is shown in Table 2
.
In general, all
of the root yields were lower t
han the expected
CARD 008/07 VIE
–
Development of sweet potato varieties with high quality
291
potential yields due to the unfavourable
weather in all locations. However, VC68
-
2,
VC04
-
24 and VC02
-
193 achieved higher root
yields of 13.75, 14.94 and 13.64 tonnes/ha,
respectively, than Hoang Long and the local
variety with 10.62 and 10
.13 tonnes/ha,
respectively. The location S1 had the highest
root yield of the six locations.

10.73
10.47
10.61
10.82
11.24
11.94
HT2
15.13
9.38
9.64
10.51
10.54
11.62
11.14
TM1
14.42
12.00
11.22
11.29
11.98
9.42
11.72
VC.01
14.89
10.36
9.73
10.64
8.87
9.04
10.59

14.33
13.87
14.94
VC02
-
193
19.51
12.00
11.78
14.30
13.56
10.69
13.64
Hoang Long
18.40
8.82
7.84
9.93
10.13
8.60
10.62
Local variety
18.73
10.
16
7.00
7.68
7.80
9.40
10.13

S5= Nguyen Binh, Tinh Gia, Thanh Hoa
S6= Quang Minh, Quang X
ương, Thanh Hoa
The dry matter content of vine
-
leaf of vine
-
leaves as shown in Table 3, varied from 10.62
to 12.22%. Most of the varieties had similar
values of dry matter content but N
o
8 had the
highest average dry matter content of 12.22%.
The dry matt
er content of vine
-
leaves in Bac
Giang (S2) and Thanh Hoa (S5) had high
values of 11.52 and 12.56%, respectively.
Table 3
.
Dry matter content (%) in vine
-
leaf of sweet potato varieties in Winter season 2008
Varieties
S1
S2
S3
S4
S5

11.75
11.19
12.01
11.42
13.10
11.74
11.87
TM1
10.10
11.51
11.90
11.08
12.56
9.52
11.00
VC.01
10.94
12.21
12.29
11.16
12.99
11.69
11.88
VC.68
-
2
12.90
8.75
10.28
10.34

11.30
11.25
13.23
9.37
11.00
Hoang Long
10.14
12.08
12.08
11.
89
13.51
10.64
11.72
Local variety
10.01
11.42
11.54
13.31
13.31
9.88
11.58
Mean
10.81
11.52
11.50
11.06
12.56
10.43
11.31

TT
Thuy,
TQ
Anh,
NP
Anh,
DT
Lieu,
NT
Hoai,
L
.
Copeland, P
.
Sharp
&
R
.
Trethowan
2
92
-
The vine
-
leaf yields
:
The vine
-
leaf yields of the
new varieties in Bac Giang and Than

S4
S5
S6
Mean
KL5
8.36
3.71
6.51
8.69
10.83
3.36
6.91
KB1
7.87
3.24
4.31
8.37
10.16
3.24
6.20
N
o
8
8.71
3.91
4.96
8.60
11.23
3.71
6.85

2.44
9.48
12.66
4.64
6.82
VC.97
-
6
-
3
7.69
11.13
4.69
8.99
11.13
3.64
7.88
VC 04
-
24
10.64
3.64
5.40
9.06
11.45
3.42
7.27
VC02
-
193

7.04
LSD
1.33
1.52
1.38
0.86
1.21
1.37
CV%
9.50
19.20
15.40
5.80
6.30
20.50
Note:
S1= Bich Son
-
Viet Yen, Bac Giang
S2= Cao Xa, Tan Yen, Bac Giang
S3= Dong Quang, Dong Son, Thanh Hoa
S4= Mai Trung, Hiep Hoa, Bac Giang
S5= Nguyen Binh, Tinh Gia, Thanh Hoa
S6= Quang Minh, Quang X
ương, Thanh Hoa
3.2
Evaluate and select new potato
varieties at the FCRI’ farm
To compare with the other locations, these
sweet potato varieties were also planted in

Vine
-
leaf
yield
(tonnes/ha)
Root yield
(ton
nes/ha)
R
oot
weight
(g)
Number
of root
per plant
(#)
Grade ratio
(%)
>100g
30
-
100g
<30g
KL5
9.8
17.3
65.7
6.6
45.5
23.3

7.0
31.5
33.7
34.8
VC.01
10.7
15.3
69.4
5.5
39.8
36.5
23.8
VC.68
-
2
6.8
13.5
49.6
6.8
33.9
23.8
42.3
VC97
-
6
-
3
10.5
14.5
55.9

17.8
21.9
60.2
CV (%)
6.2
5.9
14.1
11.6
11.7
17.5
13.2
LSD0.05
1.28
1.28
14.2
1.10
5.97
7.0
6.97
Some quality criteria also were determined for
the sweet potato root from all the varieties. The
table 6 below presented that:
-
VC0
1 and VC68
-
2 achieved the highest
dry matter contents with 27.5
% and 26%,
respectively in all the varieties. These two

%)
RDMY
(tonnes/ha)
SLDMC
(%)
SLDMY
(tonnes/ha)
Sweetness
1
-
5*
Softness
1
-
5*
KL5
20.5
3.5
8.1
0.8
5
1
KB1
21.9
2.6
9.2
0.8
3
1
No8

26.0
3.5
9.3
0.6
2
5
VC97
-
6
-
3
22.6
3.3
9.5
1.0
4
1
VC04
-
24
19.0
4.1
7.2
0.7
4
1
VC02
-
193
23.9

-
RDMY =Root dry matter yield
-
SLDMY= Vine
-
leaf dry matter yield
-
1
-
5*: score 1= not soft, not sweet;
score 3= soft, relative sweet; score 5 = very soft,
very sweet
CARD 008/07 VIE
–
Development of sweet potato varieties with high quality
294
3.
3
Evaluate and select new potato
varieties at Quang Tri in Spring
season 2009
At Quang Tri, the sweet potato crop was
harvested in April 2009. The root, the vine and
leaves were taken to determine for the weight,
the yield and the other
quantity criteria (Table
7).
-
The vine
-

leaf
yield
(tonnes/ha)
Root
yield
(tonnes/
ha)
Average
root
weight
(g)
Number
of root
per plant
(#)
Grade ratio (%)
>100g
30
-
100g
<30g
KL5
3
1.1
19.3
106.9
4.5
28.5
36.2
35.3

32.1
31.3
VC.01
28.7
10.6
74.5
3.6
39.7
40.0
20.3
VC68
-
2
19.7
18.9
106.8
4.4
36.5
32.8
30.7
VC.97
-
6
-
3
23.6
19.5
108.4
4.5
30.9

Local
23.6
14.9
107.1
3.5
40.4
33.4
26.2
CV(%)
3.0
4.3
8.3
8.6
-
-
-
LSD 0.05
1.2
1.3
14.7
0.6
-
-
-
The quality criteria of dry matter content and
yield of root and vine
-
leaf, the sweetness and
softness of root were also determined for all
sweet potato varieties planted in Quang Tri at

-
leaf.
CARD 008/07 VIE
–
Development of sweet potato varieties with high quality
295
Table 8
.
Yields, dry matter content, sensor
y value of sweet potato varieties in
Quang Tri (Spring
season 2009)
Varieties
RDMC
(
%)
RDMY
(tonnes/ha)
SLDMC
(%)
SLDMY
(tonnes/ha)
Sweetness
1
-
5*
Softness
1
-
5*

28.7
3.6
13.3
3.8
3
1
VC.01
35.2
4.0
14.0
3.7
4
5
VC68
-
2
30.6
2.7
13.8
5.7
2
5
VC.97
-
6
-
3
31.2
3.1
13.1

3.0
13.0
4.
5
5
1
CV(%)
3.2
4.6
4.0
5.3
-
-
LSD(0.05)
1.6
0.3
0.9
0.4
-
-
* Note:
-
RDMC= Root dry matter content
-
SLDMC= Vine
-
leaf dry matter content
-
RDMY =Root dry matter yield
-

on the yields of vine
-
leaf and root of all sweet
potato varieties at the locations. The varieties
VC68
-
2, VC04
-
24 and VC02
-
193 have
achieved the best roo
t yields of 13.75, 14.94
and 13.64 tonnes/ha, respectively, which was
higher than those of Hoang Long and the
local check variety.
-
At the FCRI’s experiment station the
varieties VC04
-
24 and VC02
-
193 have
produced the highest root yields with 21.7
and
18.9 tonnes/ha while VC01 and VC68
-
2
provided the best sweetness and softness.
-

Hoai,
L
.
Copeland, P
.
Sharp
&
R
.
Trethowan
296
4.2
Recommendations
Variety VC68
-
2 should be further improved
for quality trait and VC04
-
24 and VC02
-
193
for high
yield in order to introduce new sweet
potato varieties for growing in Bac Giang,
Thanh Hoa and Quang Tri provinces in the
future.
References
1. Đinh The Loc,
Sweet potato and cultivation
technology

Ph.D
. Dissertation, Univ. of the Philippines at
Losbanos, 1994.
6. Vu Tuyen Hoang and et al.
The breeding
result of sweet potato with high quality.
Results research 1986
-
1990 of FCRI,
Agriculture Publishing House, 1990.
7.
Vu Van Che, Nguyen Tan Hinh, Truong
Cong Tuyen, Nguyen Thi Thuy Hoai and Dang
Thi Hue.
The breeding result of sweet potato
with high dry matter content from material
CIP and Japanese.
Results research of FCRI
1999
-
2001, Agriculture Publishing House
2002. P.101
-
104.