Sweet Potato Research for Enhancing Food and Nutrition

Volume 19(4), 62- 70, 2015 JOURNAL of Horticulture, Forestry and Biotechnology www.journal-hfb.usab-tm.ro

Sweet Potato Research for Enhancing Food and Nutrition Security in Nepal

Prakash Bhattarai

National Potato Research Programme, NARC, Khumaltar, Lalitpur, Nepal

Corresponding author. Email: [email protected]

Abstract

Sweet potato [Ipomoea batatas (L.)Lam],world's seventh most

important and underexploited food crop is grown throughout the mid hills and

terai region for kitchen garden purpose in Nepal. Vitality and potentiality of

this crop in the food security of small and marginal farmers could not be

ignored and overlooked and maximum advantage of this crop need to be

explored. It is good sources of vitamins, minerals, micronutrients as well as

dietary fiber. Orange flesh sweet potatoes (OFSP) are additionally enriched

with β-carotene, the precursor of Vitamin A. Maximum genetic diversity of

sweet potato in on- farm conservation of Nepal. Farmers have been growing

only local landraces since long time in Nepal due to unavailability of any

appropriate high yielding, nutrient enriched, commercial and standard variety

of sweet potato and no any systematic research was carried out by the

concern office of agriculture research and development in past. With this in

view, National Potato Research Programme (NPRP) had been started

research on sweet potato since 2009 AD .For the initiation of sweet potato

research, 21 orange fleshed sweet potato clones were brought from

International Potato Centre (CIP) and three local genotypes collected from

eastern part of country were multiplied and tested under preliminary and Initial

evaluation trial (IET) at Khumaltar, Pokhara and Tarahara during 2009/10 to

2011/12. Ten outstanding orange fleshed along with two check genotypes

selected from IET were further verified as a coordinated varietal trial (CVT)

from 2012/13 to 2013/14 at RARS, Tarahara, ARS, Pokhara , ARS, Surkhet

and RARS, Parwanipur. Results from several on-station studies conducted

during the year of 2009/10 to 2013/14 demonstrated that five outstanding

sweet potato genotypes, namely CIP 440015,CIP 440267, CIP 440328, CIP

440021 and CIP 440012, are superior for their growth and yield

characteristics. These five promising genotypes were promoted for

Coordinated farmers' field trials(CFFT) and are being tested and compared

at farmers field level from 2014/15. Germplasm collection and maintenance of

local as well as exotic genotypes is continued and altogether 79 different

sweet potato genotypes have been maintained under field conditions. In

addition to this, other points like coordination between research and

extension, prioritization, awareness on it's nutritional importance, farmers

motivation, enhancing collaboration and linkage with stakeholders, facilities

for molecular and nutritional characterization are equally important.

Key words

evaluation, food security,

germplasm,

promising

genotypes, research, sweet

potato, variety

Sweet potato (2n = 6x = 90), the world’s seventh most important food crop after wheat, rice, maize, potato, barley, and cassava [5], is a tropical perennial crop usually grown as an annual. More than 95 % of the global sweet potato is grown in developing country[10].Worldwide it has been grown up to 1800 masl [9,6] and also grown from plains to the high hills up to 2500 masl having with at least five frost free months [1]. It is Regarded as poor man’s crop due to it’s low input requirement and ability to produce under adverse weather and soil conditions [8]. In Nepal l, it is one of the neglected and underexploited food crop but has religious and cultural values and
62

tubers are harvested for Thula Ekadashi and Makar Sankranti (Festivals of Hindus). it is grown throughout the mid hills and Terai region in kitchen garden [6]. From the production point of view, Nepal still lacks reliable statistics on areas and production of sweet potato. Most of the middle hill districts and terai are main sweet potato growing areas of the country [7]. Districts like Kabhrepalanchok, Sindhuli, Dhading, Dhankuta , Ilam, Gorkha, Tanahu, Surkhet, Rolpa, Siraha, Saptari, Jhapa,Sunsari, Dhanusha, Banke, Bardiya, Rupandehi, Nawalparasi are main sweet potato growing areas of the country.

Vitamin A deficiency is a problem of public health in the country especially in ethnic communities and schedule cast groups. In the flood prone and marginalized areas of eastern and western terai of Nepal, sweet potato would have great role for food and nutrition security. It is good sources of vitamin C and E as well as dietary fiber, potassium, and iron. The orange and red-fleshed forms of sweet potato are additionally enriched with β-carotene, the precursor of Vitamin A .Consumption of 125 g of storage roots of OFSP can fulfill the recommended daily amount of vitamin A for child and adult. It can be a miracle food crop to combat with the micronutrient deficiencies prevailing among the children, and pregnant and lactating women, especially in rural communities. In addition, sweet potato starch used for manufacture of paper, ink, paint, chemical products, feed stuff and organic fertilizer production. This crop is not commercialized due to lack of high yielding, nutrient enriched variety and research. Farmers have been growing only local landraces since long time in Nepal due to unavailability of any commercial and standard variety of sweet potato and no systematic research and development work was carried out from government level in past. Low yield of present local landraces, sustainability problems of yield, lack of conservation and characterization of genetic resources, lack of quality planting materials of improved varieties and knowledge on production technology are the major problems associated with this crop. In addition to that, maximum genetic diversity of sweet potato in on- farm conservation of Nepal. Unknowingly, farmers have been growing very potential landraces of sweet potato might be extremely useful for future breeding programme to increase production and productivity. So, it is very essential to collect and conserve them for characterization and promotion. Considering above facts, the research in sweet potato had been started since 2010 by NPRP.
Study Methodology
As on station trials, Preliminary Evaluation Trials (PETs) were conducted at NPRP, Khumaltar, Lalitpur, IETs at NPRP, Khumaltar, ARS(Hort), Pokhara, ARS, Surkhet, RARS, Tarahara and Nepalgunj. Likewise , CVTs were conducted at ARS (Hort), Pokhara, ARS, Surkhet, RARS, Tarahara and Parwanipur. CFFTs have just initiated in outreach sites of RARS Lumle, RARS, Tarahara, ARS, Surkhet and Kusadevi, Kavrepalanchok. The plot size for IETs were 5.4 m2 with two replications and CVTs (7.2 m2) with three replications in all locations. Experimental plots in all the locations were fertilized at the rate of 30:30:50 kg NPK along with 20 mt compost per hectare as basal dose. Two to three nodal stem cuttings were planted at 60×30 cm row to row and plant to plant spacing. Vine and leaf characters (percent ground cover, plant type, vine pigmentation, vine growth rate, shape of central

leaf lobe, petiole pigmentation, flowering habit etc) at its vegetative stage and fresh weight of foliage, pest damage, tuber characters (skin color, flesh color, tuber number and weight plot wise and tuber yield t/ha) at harvest period were observed during study. In case of germplasm, in vitro plantlets from abroad and either stem cuttings or roots from different part of country were collected , multiplied and conserved.
Research Activities and Findings Germplasm
Plant genetics resources are basic raw material for improvement of any crop plant. A wider genetic diversity is fundamental for the development of new variety with good quality and higher yield. This diversity is contained in traditional varieties and modern cultivars, as well as wild relatives of the crop and other wild plant species, special genetic stocks as parental lines and genetic stock with known attributes that can be used now or in the future. Due to these reasons, few germplasm of OFSP genotypes were collected from CIP, Lima , Peru and local genotypes from different part of the country. Introduced genotypes have been conserved and maintained under in vivo at NPRP, Khumaltar, Lalitpur.
Germplasm introduction
Introduction of plant genotype to a new environment. It is done to use the introduced genotypes in a crop improvement programme and commercial cultivation after adaptation. It involves procurement, quarantine, cataloguing, evaluation, documentation, multiplication and distribution. Introduction are two types: (a)Foreign introduction or exotic collection (b)Indigenous introduction/local collection In 2009/10 (2066/67), 21 exotic orange- fleshed clones were received from International Potato Centre (CIP), Lima , Peru and were multiplied in in vitro/or screen house condition. Till 2014/15, 64 local sweet potato genotypes have been collected from different part of country. Altogether 85 different sweet potato genotypes have been collected by NPRP( Table 1).
Germplasm conservation and maintenance
Conservation is preservation of plant genetic resources or genetic diversity for use in the present as well in future. Conservation of germplasm secures the availability of biodiversity for farmers, breeding and research for the use of future generation. Altogether 79 different sweet potato genotypes have been maintained under field conditions in NPRP, Khumaltar, Lalitpur (Table 1). Six local collections did not emerged and lost in field condition. Collection and maintenance of local as well as exotic germplasm of sweet potato will be continued over times in the programme.In addition ,12 different sweet potato genotypes had been
63

maintained in RARS, Tarahara , ARS, Malepatan, Pokhara, RARS, Nepalgunj and ARS, Surkhet. But, only Tarahara farm still maintained and other two farm

lost and mixed maintained germplasm due to lack of
proper care.

Fig.1. Aspects of germplasm conservation and harvesting of sweet potato genotypes in Nepal Table 1

List of in vivo sweet potato germplasm collection and maintenance in NPRP, 2014/15

S.

CIP Number

Code

Variety

Origin

Received Date

Source

N

1 400039

CIP-10-01

10-C-1

DOM

Feb. 6, 2010

CIP, Peru

2 400917

CIP-10-02

Comal

ECU

Feb. 6, 2010

CIP, Peru

3 440001

CIP-10-03

Resisto

USA

Feb. 6, 2010

CIP, Peru

4 440007

CIP-10-04

W-208

USA

Feb. 6, 2010

CIP, Peru

5 440008

CIP-10-05

W-213

USA

Feb. 6, 2010

CIP, Peru

6 440012

CIP-10-06

W-217

USA

Feb. 6, 2010

CIP, Peru

7 440014

CIP-10-07

W-219

USA

Feb. 6, 2010

CIP, Peru

8 440015

CIP-10-08

W-220

USA

Feb. 6, 2010

CIP, Peru

9 440020

CIP-10-09

W-225

USA

Feb. 6, 2010

CIP, Peru

10 440021

CIP-10-10

W-226

USA

Feb. 6, 2010

CIP, Peru

11 440047

CIP-10-11

Bugsbunny

PRI

Feb. 6, 2010

CIP, Peru

12 440099

CIP-10-12

TIS 9101

NGA

Feb. 6, 2010

CIP, Peru

13 440112

CIP-10-13

Centennial

USA

Feb. 6, 2010

CIP, Peru

14 440135

CIP-10-14

Travis

USA

Feb. 6, 2010

CIP, Peru

15 440185

CIP-10-15

L 0-323

USA

Feb. 6, 2010

CIP, Peru

16 440267

CIP-10-16

Hung Loc 4

VNM

Feb. 6, 2010

CIP, Peru

17 440287

CIP-10-17

VSP 3

PHL

Feb. 6, 2010

CIP, Peru

18 440328

CIP-10-18

AVRDC-CN

TWN

Feb. 6, 2010

CIP, Peru

1840-284

19 440513

CIP-10-19

Koganesengan JPN

Feb. 6, 2010

CIP, Peru

20 441538

CIP-10-20

Tenian

USA

Feb. 6, 2010

CIP, Peru

21 441624

CIP-10-21

L 4-13

USA

Feb. 6, 2010

CIP, Peru

22 Japanese Red

HRD-10-01 -

JPN

2010

HRD, Nepal

23 Dhankuta Red-1

KCU-10-01 -

Dhankuta

2010

Farmer

24 Dhankuta Red-2

KCU-10-02 -

Dhankuta

2010

Farmer

25 Sunsari Red-1

KCU-10-03 -

Sunsari

2010

Farmer

26 Helen

BMS-12-01 -

-

June 2012

Helen Keller

27 Bengali Red

KCU-12-01 -

India

June 2012

Market

28 Sangachowk White KCU-12-02 -

Sindhupalchowk Nov. 22, 2012 Market

29 Panchkhal Red

BMS-12-02 -

Sindhupalchowk Nov. 22, 2012 Farmer

30 Lamatar White

TPG-12-01

-

Lalitpur

Nov. 22, 2012 Farmer

31 Batakeshwor White DC-12-01

-

Dhanusa

Dec. 13, 2012 Farmer

32 Shantipur Red

DC-12-02

-

Dhanusa

Dec. 13, 2012 Farmer

33 Barhathwa White KCU-12-03 -

Sarlahi

Dec. 14, 2012 Farmer

64

S.

CIP Number

N

34 Hansposa White

35 Kentucky Red

36 Haibung White

37 Haibung Red

38 Fendikuna White

39 Tarkutar White

40 Paundi White

41 Majhigaun White

42 Bensisahar Red

43 Chipleti White

44 Fistar White

45 Parewatar White

46 Kalidaha White

47 Salang White

48 Japanese Purple

49 Bhantabari Red

50 Bhantabari White

51 Tareni White

52 Balewa White

53 Balewa Red 54 Chyanglitar White

55 Chyanglitar Red 56 Jorsal White

57 Pallotar Red

58 Limba White

59 Chomagu White 60 Mangalbare Red 61 Barbote Red 62 Bodhe White 63 Dhukurpani White
64 Tarabari White

65 Bhangbari White 66 Fadani White 67 Lamatar Red

68 Kheruwa White

69 Bensisahar White

70 Hybrid White

71 Motipur White

72 Motipur Red 73 Gajrahiya Orange 74 Thutobari White

75 Tribeni White

76 Tribeni Red 77 Bijuwar White 78 Dhanwang Red 79 Kavra White

Code
KCU-13-01 NSC-13-01 BMS-13-01 BMS-13-02 BMS-13-03 BMS-13-04 BMS-13-05 BMS-13-06 BMS-13-07 BMS-13-08 BT-13-01 BT-13-02 BT-13-03 BT-13-04 BMS-13-10 BMS-13-11 BMS-13-12 BMS-13-13 BMS-13-14 BMS-13-15 BMS-13-16 BMS-13-17 YKS-13-01 YKS-13-02
YKS-13-03
YKS-13-04 YKS-13-05 YKS-13-06 YKS-13-07 YKS-13-08
YKS-13-09
YKS-13-10 YKS-13-11 YKS-13-12
YKS-13-13
BMS-13-09
BMS-14-01
BMS-14-02
BMS-14-03 BMS-14-04 BMS-14-05
BMS-14-06
BMS-14-07 BMS-14-08 KCU-14-01 KCU-14-02

Variety
-
-
-
-
-
-
-
-
-
-
-
-

Origin
Sunsari Sindhupalchowk Sindhupalchowk Lamjung Lamjung Lamjung Lamjung Lamjung Lamjung Dhading Dhading Dhading Dhading Japan Sunsari Sunsari Rupandehi
Baglung Baglung
Gorkha Gorkha Panchthar
Panchthat
Panchthat
Panchthar Ilam Ilam Ilam Jhapa
Jhapa
Jhapa Morang
Morang
Morang
Lamjung
Kapilvastu
Kapilvastu
Kapilvastu Kapilvastu
Nawalparasi
Nawalparasi
Nawalparasi Pyuthan
Salyan Salyan

Received Date
Jan. 19, 2013 Feb. 12, 2013 Mar. 18, 2013 M ar. 18, 2013 Jul. 5, 2013 Jul. 5, 2013 Jul. 5, 2013 Jul. 5, 2013 Jul. 5, 2013 Jul. 5, 2013 Jul. 23, 2013 Jul. 23, 2013 Jul. 23, 2013 Jul. 23, 2013 Aug. 21,2013 Aug. 24, 2013 Aug. 24, 2013 Sep. 11, 2013
Nov. 22, 2013 Nov. 22, 2013
Nov. 25, 2013 Nov. 25, 2013 Dec. 9, 2013
Dec. 9, 2013
Dec. 9, 2013
Dec. 9, 2013 Dec. 11, 2013 Dec. 11, 2013 Dec. 11, 2013 Dec. 12, 2013
Dec. 12, 2013
Dec. 12, 2013 Dec. 13, 2013
Dec. 13, 2013
Dec. 13, 2013
Jul. 15, 2014
Jan. 11, 2014
Jan. 11, 2014
Jan. 11, 2014 Jan. 11, 2014
Jan. 13, 2014
Jan. 13, 2014
Jan. 13, 2014 Mar. 3, 2014
Dec. 8, 2014 Dec. 8, 2014

Table 1 Source
Farmer Nigale Farmer Farmer Farmer Farmer Farmer Farmer DADO Farmer Farmer Farmer Farmer Farmer Food Re.Div Famer Famer Famer Famer
Famer Famer
Famer Famer Famer
Famer
Famer
Famer Famer Famer Famer Famer
Famer
Famer Famer
Famer
Famer
Famer
Famer
Famer
Famer Market
Market
Market
Famer Farmer Farmer

65

S. N 80 81 82 83
84
85 Source: [4]

CIP Number
Syuja White Kimchaur White Satbariya Red Satbariya White Pakuri Sweet Benimasari

Code
KCU-14-03 KCU-14-04 PB-15-01 PB-15-02 BMS-15-01 BMS-15-02

Variety
-

Origin
Dang Salyan Dang Dang Lalitpur Lalitpur

Received Date

Table 1 Source

Dec. 8, 2014 Dec. 8, 2014 Jan. 3, 2015 Jan. 3, 2015
April 18,2015
April 18,2015

Farmer Farmer Farmer Farmer Farmer
Farmer

Varietal Evaluation
Under sweet potato variety improvement program, NPRP is trying to follow similar varietal evaluation scheme as followed in potato varietal improvement scheme. Collected germplasm are multiplied under in vitro and/or screen house conditions, followed by preliminary evaluation in observation trials under field conditions at Khumaltar and/or appropriate locations. The best performing materials are further tested as Initial Evaluation Trial (IET), and later as Coordinated Varietal Trial (CVT) in different collaborative farms and stations. Promising lines from CVT are further promoted to Coordinated Farmers’ Field Trial (CFFT) carried out at out-reach research sites of different stations and further one time under farmers’ acceptance test (FAT) and the most performing clone are recommended for commercial cultivation in respective locations.
Preliminary Evaluation Trial (PET)
Newly introduced clones are evaluated in close supervision of breeder/scientist under field conditions and or appropriate locations. First time, PET of sweet potato was conducted at Khumaltar in 2009/10 (2066/67) and 21 CIP clones (Table 1) and four local collections Dhankuta-1, Dhankuta-2, Sunsari-1 and Japanese Red were included in PET. This is continue process to evaluate the new clones for Initial evaluation trial where plant and tuber characteristics are observed.
.

Initial Evaluation Trial (IET)

The best performing clones from PET are further tested as IET. It is first step of on station trial conducted in representative testing site of terai and mid hills. It is the testing of new clones for yield potentiality, adoptability in different agro-climatic zones and major diseases and pest response. Number of sweet potato genotypes in this trial varies from 20 to 40 depends on number of genotypes introduced or selected prior to conduct this experiment. This trial must be conducted at least two years at the same locations. During the year 2010/11( 2067/68), IET was conducted at RARS Tarahara, ARS, Pokhara and NPRP, Khumaltar.Trial was repeated in the year 2011/2011(2068/69) at same locations and one set was at RARS, Nepalgunj. Twenty five SP clones (SN 1-25 in Table 1) as evaluated in preliminary observation trial were tested in IET. Necessary observations like vine characters, leaf characters and tuber characteristics were taken during study.

Coordinated Varietal Trials (CVT)

Promising sweet potato clones based on the

performance of the tested clone on IET of two years

are tested under on stations conditions in different

locations of the country in coordinated way. The

number of sweet potato clones varies from 10 to 15 in

CVT. CVT must be conducted at least two years at the

same locations. NPRP had conducted CVT in ARS,

Pokhara, RARS,Tarahara, Parwanipur and ARS,

Surkhet during the year 2012/13 and 2013/14. Ten

outstanding orange-fleshed sweet potato along with

two check genotypes selected from IET were further

assessed for their vegetative and yield characteristics

under

CVT

(Table

2,3

&4)

66

Table 2

Yield of sweet potato clones under Coordinated Varietal Trial (CVT) at ARS (Horticulture), Pokhara, 2012/13

Clones

Foliage FW (t/ha)

Yield (t/ha)

Pest damage†

General evaluation‡

CIP 400039

3.98

1.09

7.0

1.0

CIP 440007

5.67

2.75

5.7

2.3

CIP 440012

4.81

9.36

4.3

6.3

CIP 440015

5.60

3.84

5.0

4.0

CIP 440021

2.74

3.75

4.7

2.7

CIP 440135

4.36

2.57

5.7

1.7

CIP 440185

2.32

4.08

4.7

3.3

CIP 440267

3.14

5.18

5.7

4.3

CIP 440328

6.92

2.96

7.0

2.0

CIP 441624

4.34

1.93

5.7

1.0

Japanese Red 9.64

2.50

5.0

1.3

Dhankuta-1

7.38

1.49

4.0

1.0

P

0.0116

LSD (0.05)

3.647

†: 0 = No damage, 3 = low damage, 5 = moderately damaged, 7 = highly damagesd, 9 = totally damaged

‡: 1 = very poor, 5 = average, 9 = Excellent

Source: [2]

Yield of sweet potato clones under Coordinated Varietal Trial (CVT) at RARS,

Tarahara and RARS, Parwanipur, 2012/13

Yield (t/ha)

Clones

RARS, Tarahara

RARS, Parwanipur

CIP 400039

1.3

8.74

CIP 440007

2.9

4.31

CIP 440012

4.6

5.33

CIP 440015

2.2

7.24

CIP 440021

2.9

5.67

CIP 440135

1.0

5.29

CIP 440185

2.1

8.12

CIP 440267

0.5

8.35

CIP 440328

3.3

7.82

CIP 441624

3.5

3.29

Japanese Red

2.7

3.17

Dhankuta-1

4.4

4.35

P

0.0016

0.7345

LSD (0.05)

1.773

ns

Table 3

Source: [2]

67

Table 4

Yield of sweet potato clones under Coordinated Varietal Trial (CVT) at different locations of Nepal, 2013/14

Locations† & (Yield t/ha)

Regression

Genotypes

ARSM ARSD RARST Genotype Mean bi

CIP 440015

12.6

11.3

13.5

12.5

CIP 440021

14.0

19.9

15.7

16.5

CIP 440012

10.0

15.4

18.9

14.8

CIP 440185

10.1

8.2

6.3

8.2

CIP 400039

12.6

3.3

8.9

8.3

CIP 440328

16.3

14.7

25.0

18.7

CIP 441624

2.7

6.5

7.2

5.5

0.14 0.72 2.36 -0.98 -1.37 1.92 1.25

CIP 440135

8.8

13.3

8.9

10.3

CIP 440007

6.4

6.5

6.6

6.5

CIP 440267

13.9

31.4

26.5

23.9

Japanese Red 10.9

12.3

10.5

11.2

Dhankuta-1

3.1

8.2

18.2

9.8

0.27 0.05 3.88 -0.01 3.77

Location Mean 10.1

12.6

13.9

12.2

Env. Index, Ij -2.1

0.4

1.7

† ARSM = Agriculture Research Station (Horticulture), Malepatan, Pokhara; ARSD = Agriculture

Research Station, Darhrathpur, Surkhet and RARST = Regional Agriculture Research Station, Tarahara,

Sunsari.

Source: [3]

It is on farm evaluation of the promising clones in on station trials. Researchers, farmers and extension workers are involved to select disired variety. CFFT is conducted with the collaboration of research stations and Outreach Research Division. Advanced clones selected from CVT are kept in CFFT. At least two variety; one farmer's prefer and other improved check are included as checks. Experiment should be repeated at least two years for further verification. Four outstanding sweet potato genotypes, namely CIP 440267, CIP 440328, CIP 440021 and CIP 440012, had been identified from 2nd year CVT evaluation in ARS (Hort), Malepatan, Pokhara; RARS, Tarahara and ARS, Surkhet. The combined analysis of two years CVT revealed an additional fifth genotype CIP 440015 as an outstanding one. So, altogether these five promising genotypes need to be promoted and compared in farmers' field under CFFT which was initiated in different outreach sites of the respective research station throughout the country since 2014/15.The highly preferred clones in CFFTs will be further verified under farmers' field condition as farmer's acceptance tests (FATs) prior to release the commercial varieties.

Problems and Constraints for Sweet Potato Research
Lack of high yielding commercial varieties



Lack of coordination between research and

extension



Neglected crop and not prioritized from the

government level



Insufficient research manpower



Difficult to convince farmers for CFFT and

field not available easily, they are not interested to

grow sweet potato, if they got potato or other vegetable



Only religious and cultural value in our

community



Lack of knowledge about it's nutritional

importance



Lack of seriousness in collaborative research

farm for planting trial, data recording and germplasm

conservations



Infestation of sweet potato weevil and rats



Lack of root/ tuber storage facility for longer

period



Lack of lab facilities for molecular and

nutritional characterization of sweet potato genotypes

Few stations of NARC have lost all CIP clones

conserved at field level due to improper care.

Major Achievements

Five outstanding sweet potato genotypes, namely CIP 440267, CIP 440328, CIP 440021, CIP 440015 and CIP 440012 had been identified from series of experiment held at station level and were promoted in farmer's field condition under CFFT. In addition to this, germplasm collection and maintenance of local as well as exotic genotypes is continued and altogether 79 different sweet potato genotypes have been maintained under field conditions in NPRP, Khumaltar,Lalitpur

68

Fig. 2. Promising genotypes of sweet potato

Suggested Future Work Plan



Introduction of high quality sweet potato

clones from abroad



Genetic diversity can be detected based on

morphological traits and DNA finger printing.

Morphological traits are highly influenced by

environment. So, DNA finger printing is an important

approach to identify duplicates in the germplasm

collections at gene level.



Molecular and nutritional characterization of

sweet potato clones



Studies on disease and insect management

sector



Develop suitable storage technique to

minimize storage loss

Initiate study for post harvest and processing products

References

1. Annual report (2009/10). National Potato Research

Programme, Nepal Agricultural Research Council

(NARC), Khumaltar, Lalitpur, p. 92-93

2. Annual report (2012/13). National Potato Research

Programme, Nepal agricultural Research Council

(NARC), Khumaltar, Lalitpur, 120 pp.

3. Annual report (2013/14). National Potato Research

Programme, Nepal agricultural Research Council

(NARC), Khumaltar, Lalitpur, 88 pp.

4. Annual report (2014/15). National Potato Research

Programme, Nepal agricultural Research Council

(NARC), Khumaltar, Lalitpur

5.

FAOSTAT.

2007.

June

2009.

.

6. Gautam, D. M. 1981. Effect of pre-harvest vine

removal on quality and post harvest behavior of sweet

potato. Nepalese Horticulture 2 (1):25-30.

7. Lohani, S. N. 1981. Sharkharkanda. In: Nepal Ko

Krishi Bali. Pub. D. Lohani, Kathmandu, p. 366-370.

69

8. Ndolo, P.J., Mcharo, T., Carey, E.E. Gichuki, S.T. C. Ndinya, C., Malinga’a, J., 2001. Participatory onfarm selection of sweet potato varieties in western Kenya. African Crop Science Journal 9 (1) 41-48. 9. Sah, B.B. 1991. Nepalma Shakarkhanda Khetiko parichaya. In: Krishi traimashik Patrika. CWDS, Nalaju. Kathmandu, Nepal year 2 No. 3 p. 23-26.

10. Sharma, B.P. 2014. Potato Research in Nepal:
Enhancing Productivity and food security. Proceedings
of the National Potato Research Workshop, 31 March2nd April, 2014, Khumaltar, Lalitpur, p.1-10.

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