Bộ Nông nghiệp và Phát triển nông thôn (MARD)
008/07VIE
Selection and development sweet potato varieties with
high root quality for food processing in Northern and
Central of Vietnam
MS4
Evaluation and selection of new sweet potato varieties
in Bac Giang, Thanh Hoa and Quang Tri 2008-2009

July 2008

2

+61 2 9351 2935
Position:
Professor
Fax:
+ 61 2 9351 2945
Organisation
Faculty of Agriculture, Food and
Natural Resources,
University of Sydney
Email:
[email protected]

In Australia: Administrative contact
Name:
Annette Vervoort
Telephone:
61 2 9351 8795
Position:
Adm. Assistant
Fax:
61 2 9351 4172
Organisation
Faculty of Agriculture, Food and
Natural Resources,
University of Sydney
Email:
[email protected]

In Vietnam
Name:

Thanh Hoa and Quang Tri priovinces from 2008 to 2009 in order to select suitable sweet potato varieties
sduited to the environmental conditions of each region.

II. AIMS
Select the best one or two sweet potato varieties with high yield and good quality for the provinces of Bac
Giang, Thanh Hoa and Quang Tri.

III. RESEARCH METHODS AND SCOPES
3.1. Methods
3.1.1. Location
1. Food Crops Research Institute
2. Bac Giang (Bich Son, Viet Yen, Ngoc Chau, Tan Yen, Mai Trung, Hiep Hoa)
3. Thanh Hoa (Nguyên Binh, Tinh Gia, Quang Luu, Quang Xuong, Dong Thanh, Dong Son)

4
4. Quang Tri (Vinh Thai, Vinh Linh, Gio Hai, Gio Linh, Hai Quy, Hai Lang,)
3.1.2. Materials
Ten varieties were collected from Food Crops Research Institute. Hoang Long and local sweet potato
varieties were the control samples.
3.1.3. Experiment type
- Randomized complete block design (RCBD)
- Study area: 11 varieties x 4 replications x 15 m
2
= 660 m
2

- Protection area: 340 m
2

- Total: = 1,000 m

Thanh Hoa and Bac Giang: 5-10
th
October, 2008
Quang Tri: 15-20
th
December, 2008
5
3.1.7. Fertilization method

Fertilizer kg /ha Kg(NPK)/ha
Cattle manure 15,000 -
Urea 150 60-70 kg N/ha
Lan Super 550 90-100 kg P/ha
Kali 220 120 kg K/ha

- Mix all of the cattle manure and Lan super as well as 30% of Urea and 30% of Kali for treament
before planting.
- Half of the remaining Urea and Kali lefts was fertilized 20-25 days after planting. The other half
was added in 40 to 45 days after planting.
3.1.8. Plant protection
Identify and control pests:
- Take out the black cut worm (Agrotis ipsilon) by hand or using recommended pesticide.
- Using trap or pesticide for beetles (Cylas spp.)
3.1.9. Irrigation
- Apply irrigation 3 days after fertilizing

3.1.10. Harvesting data collection

medium vine and leaves, deeply lobed leaves. It is able to grow strongly and regenerate quickly and is
suitable for trimming vines and leaves periodically. The vines and leaves are soft and sweet which is
suitable for livestock feed. Vine-leaf yield is 25-30 tonnes/ha. The root yield is very high, normally
achieving an average 20–22 tonnes/ha, intensively reaching 28-30 tonnes/ha.
2. Variety number 8
The variety Number 8 was created from 1b Mien Nam × Bat Luan Xuan. This variety has high yield,
short growth period 90 to 120 days. Normally, it has the root yield of 12-15 tonnes/ha, and with
intensive farming, it can reach 20-25 tons/ha. It has high adaptability to various climates.
3. Variety KB1

7
The variety KB1 was selected from open pollination breeding of mother Read derived from America
with code: 93-65-629. The young leaves of KB1 are violet while the mature leaves are triangular and
green. The root has long oblong, white skin, and ivory-white flesh.
4. Variety HT2
The variety HT2 was selected from local varieties in Ha Tay, coded: HT2. The young and mature leaves
are triangular, serrated; and light green. The root has oblong or long eliptic shape, white skin, and
highly soft flesh. Root yield can reach 20-22 tonnes/ha.
5. Variety TM1
The variety TM1 was selected from local varieties in Hai Duong, coded: TM1. The young and mature
has heart and serrated shape shaped and light green colour. The root has long eliptic shape, pink skin,
and white flesh. It can reach the root yield of 18-20 tonnes/ha.
6. Variety VC01
The variety VC01 was selected from the local varieties in Thai Binh with the code of VC01. The young
and mature leaves have heart shape with light green colour and the vines are crawling. The root has
long eliptic shape, ivory-white skin, and white flesh. Root yield can reach 18-20 tonnes/ha.
7. Variety VC68-2
The variety VC68-2 was imported from the International Potato Center (Centro Internacional de la
Papa-CIP), coded VC68-2. The young and mature leaves are dark green heart and the vines are
crawling. The root has round shape, violet skin, and ivory-white flesh. Its root yield is about 18-20

Varieties
Vine
shape
Vine
colour
Leaf
colour
Leaf
shape
Root
skin
colour
Root
shape
Root flesh
colour
1
KL5
Half
standing
Green Green
Deep
lobe
Red Long Ivory-white
2
N
o
8
Half
standing

lobe
White Long White
5
TM1
Half
standing
Green Green
Serrated
heart
Pink-
red
Long White
6
VC01 Crawling Green Green Heart
Violet-
red
Long White
7
VC68-2 Crawling
Dark
green
Dark
green
Heart Violet Round Ivory-white
8
VC97-6-3 Crawling
Light
green
Light
green

4.3.1. The climate record in Bac Giang
Sweet potato origined in a tropical climate. Therefore, it grows very well in conditions of
relatively high temperature (optimal temperature of 21-23
o
C) and with 8-10 h/day of sunlight.

Table 2: Climate record in Bac Giang, 2008

Months Average
temperatures
(
0
C)
Rain fall (mm) Relative humidity
(%)
Sunshine period
(h)
Jan 14.9 4.3 86 77
Feb 13.5 14.1 78 51
Mar 20.1 46.5 88 88
Apr 23.3 86.7 90 90
May 25.7 97.0 83 110
Jun 26.1 118.4 84 130
Jul 27.9 110.0 80 180
Aug 27.4 145.2 85 160
Sep 26.2 249.6 87 121
Oct 29.8 292.6 87 176
Nov 20.5 237.8 79 153
Dec 17.3 16.8 76 130
Source: Center of Weather Forecast in Bac Giang province

Table 3: Climate record in Bac Giang, 2009

Months Average
temperatures
(
0
C)
Rain fall (mm) Relative humidity
(%)
Sunshine period
(h)
Jan 14.9 1.4 75 95
Feb 21.9 13.3 86 55
Mar 20.5 42.3 84 54
Apr 22.7 54.3 85 65
May 24.7 98.5 86 80
Jun 25.6 120.6 87 110
Source: Center of Weather Forecast in Bac Giang province

The experiments in Bac Giang were affected by unfavourable climate conditions compared to the
normal requirements for temperature of 21-23
o
C and sunshine period of 8-10 h/day.
4.3.2. The climate record in Thanh Hoa
In Thanh Hoa, the sweet potatoes were planted on 5-10
th
October 2008 and harvested on 15
th

February 2009. The records collected from the Center of Weather Forecast of Thanh Hoa are shown in

Feb 13.5 15.1 78 31
Mar 20.1 26.5 88 106
Apr 24.3 116.7 90 110
May 26.7 97.0 83 192
Jun 28.1 188.4 84 130
Jul 28.9 110.0 80 185
Aug 28.4 145.2 85 169

11
Sep 27.2 349.6 87 121
Oct 25.7 348.2 86 92
Nov 21.7 106.0 77 129
Dec 18.6 18.6 78 107
Source: Center of Weather Forecast in Thanh Hoa province Table 5: Climate record in Thanh Hoa, 2009

Months Average
temperatures
(
0
C)
Rain fall (mm) Relative humidity
(%)
Sunshine period
(h)
Jan 16.2 8.6 78 113
2eb 22.0 39.2 88 105
Mar 19.9 35.4 89 61

C and sunshine period of
8-10 h/day.
12
Table 6: Climate record in Quang Tri, 2009

Months Average
temperatures
(
0
C)
Rain fall (mm) Relative humidity
(%)
Sunshine period
(h)
Jan 18.1 190.0 86 69
Feb 23.5 15.9 89 132
Mar 24.1 70.4 93 123
Apr 25.6 100.5 86 115
May 27.1 315.0 85 210
Jun 30.3 13.7 75 80
Source: Center of Weather Forecast in Quang Tri province

4.4. Evaluate and and select new potato varieties in Bac Giang and Thanh Hoa
In Bac Giang and Thanh Hoa, mean weight of roots harvested was determined for all of the new

S5= Nguyen Binh, Tinh Gia, Thanh Hoa S6= Quang Minh, Quang Xương, Thanh Hoa

13

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 8). 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 high 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 8: Dry matter content (%) in root of Sweet potato varieties in Winter season 2008

Varieties S1 S2 S3 S4 S5 S6 Average
KL5 20.13 20.63 19.17 20.97 18.9 20.20 20.00
KB1 18.63 26.17 19.90 21.73 19.77 23.97 21.70
N
o
8 23.37 27.87 19.50 21.23 23.83 22.47 23.05
HT2 24.60 33.50 18.57 21.37 25.10 30.73 25.65
TM1 22.50 23.7 19.07 20.87 18.67 18.20 20.50
VC.01 27.53 29.10 19.13 23.0 27.13 26.40 25.38
VC.68-2 23.57 26.13 18.90 22.43 25.23 20.23 22.75
VC.97-6-3 24.10 20.67 18.97 22.77 20.67 20.50 21.28
VC 04-24 20.33 27.20 19.33 18.87 18.20 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

VC.97-6-3 10.01 12.84 11.86 10.79 12.12 10.62 11.37
VC 04-24 10.03 12.57 11.33 9.24 11.31 10.10 10.76
VC02-193 9.54 11.31 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
Average 10.81 11.52 11.50 11.06 12.56 10.43 11.31
LSD (5%) 1.48 1.90 0.99 1.27 2.32 1.40
CV% 8.10 9.70 5.10 6.80 10.90 7.90
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 Xương, Thanh Hoa
The vine-leaf yields of the new varieties in Bac Giang and Thanh Hoa in the winter season 2008 were
calculated and presented in Table 10.
- The unfavourable climate in the winter of 2008 affected the growth of the sweet potato varieties (Table
2, 3, 4 and 5) and reduced the vine-leaf yield. The highest yield was only 8.01 tonnes/ha from TM1 while Hoang
Long and the local variety had very low yields of 5.95 and 6.85 tonnes/ha, respectively.
- In the same varieties, the vine-leaf yield in various locations were different. Therefore, evaluation of
adaptability of a variety to the environment is necessary

Table 10: Vine-leaf yield (tonnes/ha) of sweet potato in Winter season 2008

Varieties S1 S2 S3 S4 S5 S6 Average
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
HT2 6.78 4.60 6.16 7.85 10.02 4.60 6.67
TM1 8.27 4.80 6.89 9.83 13.58 4.69 8.01

N
o
8 17.78 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
VC.68-2 19.29 13.56 13.80 11.88 12.93 11.02 13.75
VC.97-6-3 15.89 13.00 9.93 11.32 10.76 10.27 11.86
VC 04-24 22.62 11.13 12.51 15.16 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
Average 17.82 11.04 10.53 11.40 11.22 10.62 12.10
LSD (5%) 1.87 1.28 2.68 0.70 0.76 1.83
CV% 6.20 6.90 15.00 3.60 4.00 10.20
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 Xương, Thanh Hoa

In the winter season 2008, the total yields of sweet potato varieties were calculated for all
locations in Bac Giang and Thanh Hoa (Table 12).
- In general, the new sweet potato varieties had total yields of 17.81-22.21 tonnes/ha, which were
higher than the control (Hoang Long) and the local variety.

16
- VC68-2, VC04-24 and VC02-193 had total yield of 20.56, 22.21 and 21.31 tonnes/ha,
respectively, much higher than Hoang Long (control) and the local varieties with values of 16.57 and 16.9
tonnes/ha, respectively.
- Among the six locations, the S1 and S5 seemed most suitable for the new sweet potato varietes