
Conservation of Rice Genetic Resources
for Food Security
*Corresponding author: Roel C. Rabara
Citation
Rabara RC, Ferrer MC, Calayugan MIC, Duldulao MD, Jara-Rabara J. Conservation of rice genetic resources for food security. Adv Food Technol Nutr Sci Open J. 2015; SE(1): S51-S56.
Copyright
© 2015 Rabara RC. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Mini Review
In the Philippines, rice is a primary agricultural crop and major caloric food source of Filipinos. Rice is produced in all of this archipelagic country’s provinces, wherein total production (~18.4 million MT) is ranked eighth in the world. PhilRice was established as a dedicated research and development arm to propel sustained rice yield growth and stability toward selfsufficient production. Supporting its rice varietal improvement program is its Gene bank, a national repository of local- and foreign-sourced rice genetic materials. Currently, there are 14,388 rice accessions conserved at PhilRice Gene bank and 44% of which are landraces and traditional rice varieties. To date, 89% of the accessions have been Phenotypically characterized. To make these genetic materials desirable parent lines for rice breeding programs, a more comprehensive phenotypic characterization and evaluation of responses to various stresses remains to be done. A gene-bank’s capacity to explore genetic potential of its holdings using molecular technology advances could pinpoint important traits in potential parent lines that are valuable in developing better rice varieties. The bottom line among the challenges of rice gene banking is striking a balance between fund resource availability and undertaking the numerous core research activities, including collection, conservation, documentation, characterization, evaluation, distribution and dissemination of rice genetic materials.
Rice genetic resources; Genebank; Ex situ conservation; Landraces; Phenotypic diversity; Germplasm characterization; Rice farming practices.
GDP: Gross Domestic Product; NPT: New Plant Type; IRRI: International Rice Research Institute.
Rice is the primary agricultural crop in the Philippines. Its production of 18.4 million
MT places the Philippines eighth among the world’s rice producing countries.1 Rice production
is a major income source for 12 million Filipino farmers and their families2 and contributes
2.2% to the Philippines Gross Domestic Product (GDP).3 Aside from being a major caloric food
source for most Filipinos, rice is a culturally important crop in the Philippines, as showcased
in many traditional festivals and rituals in various parts of this archipelagic country.4,5 In 1985,
the importance of rice to the Philippine economy led to the creation of the Philippine Rice Research
Institute (PhilRice) enacted through Executive Order 1061. PhilRice is mandated to lead
the country’s rice research and development programs that fuel the rice sector’s growth through
breeding new or improved rice varieties, and developing and promoting yield-enhancing and
component technologies.2
Breeding new or improved rice varieties would benefit from readily available germplasm
with excellent traits. Similar to most agricultural crops, the continuing infusion of genetic resources in rice breeding results in yield stability and
growth. For instance, a yield plateau was observed 28 years later
from the successful release of the IR8, the first semi-dwarf rice
plant type that was introduced in 1966.6 As such, in 1993, rice
breeders proposed the development of a New Plant Type (NPT)
focused on morphological traits rather than physiological characteristics,
because the former were easily observable in breeding
activities.6-8
Furthermore, with current pressure to feed a burgeoning
population as well as the potential effect of climate change
on food production, breeding programs have recently included
physiological traits that address such issues.9 Thus, ensuring the
availability of rice germplasm with excellent morphological and
physiological traits remains very crucial toward successfully
breeding new rice varieties expressing desired traits.
This is one major contributory role of PhilRice’s Genetic
Resources Division to any rice varietal improvement program
in the Philippines. The division, among its other research
activities, maintains the PhilRice Gene bank, a national repository
of rice genetic materials consisting of traditional landraces,
improved rice varieties, research/breeding lines, materials generated
from molecular methods, interspecific hybrids, and foreign
accessions among others.
In this review, discussion focuses on the rice germplasm
conservation program of PhilRice Gene bank and how
these genetic resources are characterized and explored. This review
also provides information about the contribution of genetic
materials in rice varietal improvement, as well as limitations,
prospects and the future direction of rice germplasm conservation.
CONTRIBUTION OF RICE GENETIC RESOURCES IN CROP
IMPROVEMENT
Rice farmers have continually contributed to rice diversity
as they cultivated selected and nurtured thousands of
rice cultivars throughout time. These cultivars represent a vast
wealth of genetic material, composed of landraces and traditional
varieties, which are good sources of important morphological
and physiological traits crucial to breeding improved rice varieties.
These rice genetic resources are key components to breeding
programs and serve as sources of important traits in developing
better rice cultivars.
In rice breeding history, several studies have identified
rice landraces as parent lines of promising new varieties. Notable
of these reports are the development of IR8, and discovery
of genes for submergence tolerance, and increasing rice yield.
Tropical Japonica rice landrace Daringan expresses the NAL1
allele responsible for significantly increasing the yield of modern
rice varieties.10 Rice landrace FR13A is the source of submergence
tolerance SUB1 QTL.11
Dubbed as miracle rice, IR8
was released in 1966 and is a cross product of two landraces:
Dee-geo-woo-gen, a Chinese semi-dwarf rice variety and Peta, a
vigorous and tall rice from Indonesia.12 The rice variety IR8 is an
important part of rice breeding programs in the Philippines as it
serves as a parent line for breeding new varieties. One study reported
that 92% of the 67 Philippine rice varieties released from
1960 to 1994 were directly related to IR8, or to IR8 through the
variety Peta as a common ancestor.13,14 The study also showed
that 57 common donor parents made these Philippine rice varieties
related to each other. At the centre of this ancestry were 19
landraces that provided the basic template for rice varietal improvement14
which highlight the importance of these germplasm
in the breeding program.
STATUS OF RICE GERMPLASM CONSERVATION AND UTILIZATION
AT PHILRICE GENE BANK
Following PhilRice establishment in 1985, conservation
of rice genetic resources through its PhilRice Genebank was
initiated with an initial collection of around 300 varieties reacquired
from the International Rice Research Institute (IRRI).15
The germplasm holdings increased through donations and various
explorations conducted around the country. A collaborative
project between PhilRice, IRRI and the Swiss Agency for
Development and Cooperation conducted in the mid-1990’s to
safeguard rice genetic resources in the country resulted in the
acquisition of 458 traditional rice varieties. To improve the management
and operation of the Genebank, an operation manual
was published serving as a protocol to the daily activities of the
Genebank.16
To date, the PhilRice Genebank is conserving 14,388
rice germplasm both from local and foreign sources (Figure 1).
Nearly half of the collections (44%) are traditional rice varieties,
while the second largest portion of the collection (32%) represents
breeding lines and improved varieties donated by various
researchers and breeders.
To fill in the gaps in the collection with emphasis on
provinces in the country with limited representation in the germplasm
collections, a PhilRice-funded project to conduct and
ecogeographic survey and collection was implemented in 2008.
A total of 387 samples were collected during the conduct of
the project. Assessment of the collections phenotypic diversity
showed high diversity in the agronomic traits measured.17 Table
1 provides a glimpse of the phenotypic diversity in selected
grain traits of the 387 rice germplasm collection. Awn length is
the only grain trait that showed low diversity because most of
the collected germplasm had no awns. Presence of awns is one
of the peculiar traits in the Indonesian bulu or javanica group
within the tropical japonica varieties.18
Analysis of correlation
among the agronomic traits showed several traits to be highly
correlated. The size of the flag leaf width was shown to be highly
correlated with some grain traits, such as grain and caryopsis
width. Flag leaves are important in grain filling stage in rice as it
contributes to 80% of the total carbohydrates as well as being a
source of photo assimilates during water stress.19

Figure 1: Composition of rice germplasm holdings, and status of characterization and evaluation of materials conserved at PhilRice Genebank.

Table 1: Diversity analysis of selected grain traits in Philippine rice germplasm. Extents of diversity in the collection were calculated based on phenotypic frequency using standardized Shannon-Weaver Diversity index (H’).
Figure 2 illustrates the germplasm diversity (A) and
(B) some of the indigenous rice farming practices (B) that were
observed during the collection mission.17 These practices could
form part of the documentation process of germplasm acquisition.
The most interesting farming practice noted was the use of
coconut palm stalks in paddy fields, resembling snakes ready to
strike, and therefore acting as decoys to scare away rats. This
practice is common to provinces of the southern Luzon region of
the country.20
Germplasm characterization and evaluation are two
important components of an efficient utilization of germplasm
materials. Germplasm evaluation is more useful if the traits measured
are of interest to breeders.21 Phenotypic characterization
based on selected traits from the internationally agreed upon
standards has been carried out on much of the germplasm conserved
at PhilRice Genebank. To date, 89% of the accessions
conserved are fully characterized (Figure 1). What is lagging is
the comprehensive phenotypic evaluation of the whole collection
based on important traits that breeders need to breed for improved
varieties. Also, evaluation of germplasm based on their
response to various stresses has commenced, but so far only
12% and 3% of the total accessions conserved underwent evaluation
for biotic and abiotic stress, respectively. For grain quality
evaluation, 34% of the collection has been screened. Phenotypic
characterization at PhilRice Genebank is usually carried out
alongside regeneration of germplasm, which explains why most
of the collections had been characterized. Germplasm evaluation
on the other hand requires technical inputs from end users who
have variable traits of interest, so this activity was carried out in
collaboration with breeders and researchers at the Institute.
Chalenges and future directions in rice genetic
resources conservation
One of the challenges in a genetic resource conservation
program is access to actual field materials. Some areas remain
remote because of poor road networks. Researchers need
to walk or hike many kilometres during exploration trips to collect
germplasm. An example is the collection trip to Aurora, one
of the Philippine provinces that is highly engaged in rice production.
Researchers had difficulty in reaching farming areas be-

Figure 2A: Diversity of rice germplasm collections. 2B: Some Filipino farmers’practices in rice production: panicle drying (top), and use of coconut palm as rat deterrent (bottom).

Figure 3: Location map of Philippine traditional rice varieties collected in Aurora province.
cause of poor farm-to-market roads. Figure 3 shows the location
of the rice varieties collected in Aurora province. Notice that the
samples collected were close to road networks, while not much
collection was done in areas that lacked road infrastructure.
Collection bias due to infrastructure is common in collection
missions because collectors tend to follow roads that
connect to main towns for the reason of efficiency, logistics
and convenience.22 This bias has been observed in numerous
germplasm collections.22-24 Hermann23 reported that most of the
Andean tuber crop collection sites sampled in Ecuador were located
near the Pan-American Highway and other major roads.
The same observation was noted by Von Bothmer and wherein
the distribution map they constructed showed that most of the
collection sites for Elymus cordilleranus were located around
major cities like La Paz (Bolivia), Lima (Peru) as well as the
Pan-American Highway in Ecuador. The same observation can
be noted for the Bolivian collection of wild potatoes, wherein
68% of the total germplasm holdings were collected within 2
km of the nearest roads.22
Geographic distribution of Huperzia
also revealed that most of the collection sites were located near
roadways.25 To gain access to areas that are far from the main
road networks, collaboration with local government and nongovernment
organization (GO and NGO) personnel could facilitate
effective and efficient collection missions.
Another challenge in germplasm conservation is managing
the increasing amount of material. Ex situ conservation is
expensive, and maintenance of these materials for a long period
of time will require sustained funding. A cost analysis done on
major gene banks around the world showed that the annual cost
could range from US $0.6 million to US $1.2 million, depending
on the location and total germplasm holdings.26
In rice genetic conservation, IRRI holds the largest collection
of rice germplasm, with 126,601 accessions conserved.
IRRI requires an annual budget of US $797,553 to conserve and
disseminate its germplasm,26
of which 61% of the total cost is allocated for labour. Since gene banks do not have unlimited
resources at their disposal, gene banks should consider the size
and scope of their collections, while conserving as much of the
total crop gene pool as possible.27
To rationalize the number of
accessions for conservation, prioritization in material acquisition
must be practiced. Another option is to reduce redundancy
in the collection by developing a core collection that would represent
the genetic spectrum of the entire conserved genebankcollection.
28 This approach was taken by Ebana, et al.28 for Japanese
rice landrace, where a core collection composed of 50 accessions
was developed, based on an original collection of 236 accessions.
They were still able to retain 87.5% of the alleles that
had been detected in the original collection.
Another challenge to rice gene banking is the availability
of phenotypic evaluation data of germplasm collections for
potential traits that can be utilized in breeding programs. One
of the major reasons why germplasm may be under-utilized is
a lack of evaluation data that breeders can use for their parental
choices.29,30
This is a common challenge in most gene banks
around the world, and it has become a major priority activity for
the Global Plan of Action on the Conservation and Sustainable
Use of Plant Genetic Resources for Food and Agriculture.29
Unlike
characterization that can be carried out during the regeneration
of germplasm, phenotypic evaluation requires more technical
expertise, financial inputs and specialized facilities, and some
gene banks do not have the ability to implement this activity.29,31
One approach to address the issue of insufficient evaluation data
in the germplasm collection is to share the responsibilities with
researchers and other germplasm users. At PhilRice, we have
collaborated with researchers from various fields (plant breeding,
entomology, plant pathology and chemistry) to generate
phenotypic evaluation data that can be useful for breeders and
other stakeholders.
In the future, the availability of genotypic and phenotypic
data from the rice germplasm conserved in gene banks
could facilitate rice breeders to efficiently and rapidly incorporate
important traits in the development of new high-yielding
varieties with enhanced tolerance to biotic and abiotic stresses.
This assumption is based on the premise that the continuing infusion
of genetic resources in rice breeding programs will result in
yield stability and growth, as previous breeding breakthroughs
have demonstrated.
The authors declare that they have no conflicts of interest.
The person (appeared in Images) has provided written permission for publication of his/her details.
1. FAOSTAT (Classic Version, 2015). Food and agriculture
organization of the United Nations: Rome, Italy. Available at:
http://faostat.fao.org/site/339/default.aspx 2011; Accessed 2015.
2. Sebastian LS, Alviola PA, Francisco SR. Bridging the rice
yield gap in the Philippines. Bridging the rice yield gap in the
Asia-Pacific region. In: Papademetriou MK, Dent, FJ, Herath
EM, eds. FAO regional office for Asia and the Pacific: Bangkok,
Thailand, 2000.
3. Cororaton CB. Philippine rice and rural poverty: an impact
analysis of market reform using CGE. International Food Policy
Research Institute (IFPRI): Washington, DC, USA. 2006.
4. Reyes LC. Banking seeds. Rice Today. 2012; 11: 16-19.
5. Aguilar FV. Rice in the Filipino diet and culture. Philippine
institute for development studies: Makati, Philippines, 2005.
6. Peng S, Khush G, Cassman K. Evolution of the new plant
ideotype for increased yield potential. Breaking the yield barrier,
Proceedings of a workshop on rice yield potential in favourable
environments. International Rice Research Institute: Los Baños,
Philippines, 1994.
7. Peng S, Khush GS, Virk P, Tang Q, Zou Y. Progress in ideotype
breeding to increase rice yield potential. Field Crops Res.
2008; 108: 32-38. doi: 10.1016/j.fcr.2008.04.001
8. Tonini A, Cabrera E. Opportunities for global rice research
in a changing world. International Rice Research Institute: Los
Baños, Philippines, 2011.
9. Mohanty S, Wassmann R, Nelson A, Moya P, Jagadish SVK.
Rice and climate change: significance for food security and vulnerability.
IRRI Discussion Paper Series No. 49. International
Rice Research Institute: Los Baños, Philippines, 2013.
10. Fujita D, Trijatmiko KR, Tagle AG, et al. NAL1 allele from a
rice landrace greatly increases yield in modern Indica cultivars.
Proc Natl Acad Sci USA. 2013; 110: 20431-20436.
11. Bailey-Serres J, Fukao T, Ronald P, Ismail A, Heuer S, Mackill
D. Submergence tolerant rice: SUB1’s journey from landrace
to modern cultivar. Rice. 2010; 3: 138-147. doi: 10.1007/
s12284-010-9048-5
12. Ronald P. A case study of rice from traditional breeding to
genomics.In: Popp JS, Jahn MM, Matlock MD, Kemper NP, eds.
In the role of biotechnology in a sustainable food supply. New
York, NY, USA: Cambridge University Press; 2012: 10.
13. de Leon JC, Carpena AL. Pedigree-based genetic diversity analysis of improved rice (Oryza sativa L.) varieties in the Philippines.
Philipp J Crop Sci. 1995; 20(1): 1-12.
14. de Leon JC. Rice that Filipinos grow and eat. PIDS discussion
paper series no. 2005-11. Philippine institute for development
studies: Makati, Philippines. Available at: http://dirp3.pids.
gov.ph/ris/dps/pidsdps0511.pdf 2005; Accessed 2015.
15. Romero GO, Rabara RC, Gergon EB, et al. Development
and utilization of the PhilRice Genebank. Philippine Science
Letter. 2011; 4(1): 24-32.
16. Rabara RC, Gergon EB, Romero GO, Nazareno ES, Newingham
MCV, Diaz CL. Manual on rice genetic resources conservation
and management. Philippine Rice Research Institute:
Nueva Ecija, Philippines, 2011.
17. Rabara RC, Ferrer MC, Newingham MCV, Diaz CL, Romero
GO. Phenotypic diversity in farmers’traditional rice varieties
in the Philippines. Agronomy. 2014; 4(2): 217-241. doi: 10.3390/
agronomy4020217
18. Vaughan DA, Lu BR, Tomooka N. The evolving story of rice
evolution. Plant Science. 2008; 174: 394-408. doi: 10.1016/j.
plantsci.2008.01.016
19. Biswal A, Kohli A. Cereal flag leaf adaptations for grain
yield under drought: knowledge status and gaps. Molecular
Breeding. 2013; 31: 749-766. doi: 10.1007/s11032-013-9847-7
20. Villegas-Pangga G. Indigenous knowledge systems and
organic farming technologies: Farmers’access to community
technological learning. Available at: http://satnetasia.org/sites/
default/files/9_Indigenous_knowledge_systems%2Borganic_
farming_tech-University_Philippines_LosBanos_paper.pdf
2013; Accessed 2015.
21. Ferguson AR. The need for characterisation and evaluation
of germplasm: Kiwifruit as an example. Euphytica. 2007;
154(3): 371-382. doi: 10.1007/s10681-006-9188-2
22. Hijmans RJ, Garrett KA, Huamán Z, Zhang DP, Schreuder
M, Bonierbale M. Assessing the geographic representativeness
of genebank collections: the case of Bolivian wild potatoes.
Conservation Biology. 14(6): 1755-1765. Available at: http://
www.diva-gis.org/docs/bias.pdf 2000
23. Hermann M. Progress report of the IBPGR research project
on the genetic resources of Andean tuber crops. AGP-IBPGR
report 89/2. International Board for Plant Genetic Resources,
Rome, 1988.
24. Von Bothmer R, Seberg O. Strategies for the collecting of
wild species. Collecting plant genetic diversity, technical guidelines.
CAB International: Wallingford, United Kingdom. 1995:
93-111.
25. Ollgaard B, Churchill SP, Balslev H, Forero E, Luteyn JL.
Diversity of Huperzia (Lycopodiaceae) in Neotropical montane
forests. Biodiversity and conservation of neotropical montane
forests. Proceedings of a symposium, New York Botanical Garden,
21-26 June 1993. New York Botanical Garden. 1995; 349-
358.
26. Schreinemachers P, Ebert AW, Wu MH. Costing the ex situ
conservation of plant genetic resources at AVRDC-the world
vegetable center. Genetic Resources and Crop Evolution. 2014;
61(4): 757-773. doi: 10.1007/s10722-013-0070-5
27. McCouch SR., McNally KL, Wang W, Hamilton RS. Genomics
of gene banks: a case study in rice. Am Jour of Botany.
2012; 99(2): 407-423. doi: 10.3732/ajb.1100385
28. Ebana K, Kojima Y, Fukuoka S, Nagamine T, Kawase M.
Development of mini core collection of Japanese rice landrace.
Breeding Science. 2008; 58: 281-291. doi: 10.1270/jsbbs.58.281
29. FAO (Food and Agriculture Organization). The second report
on the state of the world’s plant genetic resources for food
and agriculture. FAO, Rome, Italy. 2010
30. Nelson PT, Goodman MM. Evaluation of elite exotic maize
inbreds for use in temperate breeding. Crop Sci. 2008; 48: 85-92.
31. Visser B, Engels J. Setting objectives for genebanks. A guide
to effective management of germplasm collections. In: Engels
JMM, Visser L, eds. IPGRI Handbooks for Genebanks No. 6.
IPGRI, Rome, Italy, 2003.
Top
FIGURES and TABLES
Figures

Figure 1: Composition of rice germplasm holdings, and status of characterization and evaluation of materials conserved at PhilRice Genebank.

Figure 2A: Diversity of rice germplasm collections. 2B: Some Filipino farmers’practices in rice production: panicle drying (top), and use of coconut palm as rat deterrent (bottom).

Figure 3: Location map of Philippine traditional rice varieties collected in Aurora province.
Tables

Table 1: Diversity analysis of selected grain traits in Philippine rice germplasm. Extents of diversity in the collection were calculated based on phenotypic frequency using standardized Shannon-Weaver Diversity index (H’).
Top
References
1. FAOSTAT (Classic Version, 2015). Food and agriculture
organization of the United Nations: Rome, Italy. Available at:
http://faostat.fao.org/site/339/default.aspx 2011; Accessed 2015.
2. Sebastian LS, Alviola PA, Francisco SR. Bridging the rice
yield gap in the Philippines. Bridging the rice yield gap in the
Asia-Pacific region. In: Papademetriou MK, Dent, FJ, Herath
EM, eds. FAO regional office for Asia and the Pacific: Bangkok,
Thailand, 2000.
3. Cororaton CB. Philippine rice and rural poverty: an impact
analysis of market reform using CGE. International Food Policy
Research Institute (IFPRI): Washington, DC, USA. 2006.
4. Reyes LC. Banking seeds. Rice Today. 2012; 11: 16-19.
5. Aguilar FV. Rice in the Filipino diet and culture. Philippine
institute for development studies: Makati, Philippines, 2005.
6. Peng S, Khush G, Cassman K. Evolution of the new plant
ideotype for increased yield potential. Breaking the yield barrier,
Proceedings of a workshop on rice yield potential in favourable
environments. International Rice Research Institute: Los Baños,
Philippines, 1994.
7. Peng S, Khush GS, Virk P, Tang Q, Zou Y. Progress in ideotype
breeding to increase rice yield potential. Field Crops Res.
2008; 108: 32-38. doi: 10.1016/j.fcr.2008.04.001
8. Tonini A, Cabrera E. Opportunities for global rice research
in a changing world. International Rice Research Institute: Los
Baños, Philippines, 2011.
9. Mohanty S, Wassmann R, Nelson A, Moya P, Jagadish SVK.
Rice and climate change: significance for food security and vulnerability.
IRRI Discussion Paper Series No. 49. International
Rice Research Institute: Los Baños, Philippines, 2013.
10. Fujita D, Trijatmiko KR, Tagle AG, et al. NAL1 allele from a
rice landrace greatly increases yield in modern Indica cultivars.
Proc Natl Acad Sci USA. 2013; 110: 20431-20436.
11. Bailey-Serres J, Fukao T, Ronald P, Ismail A, Heuer S, Mackill
D. Submergence tolerant rice: SUB1’s journey from landrace
to modern cultivar. Rice. 2010; 3: 138-147. doi: 10.1007/
s12284-010-9048-5
12. Ronald P. A case study of rice from traditional breeding to
genomics.In: Popp JS, Jahn MM, Matlock MD, Kemper NP, eds.
In the role of biotechnology in a sustainable food supply. New
York, NY, USA: Cambridge University Press; 2012: 10.
13. de Leon JC, Carpena AL. Pedigree-based genetic diversity analysis of improved rice (Oryza sativa L.) varieties in the Philippines.
Philipp J Crop Sci. 1995; 20(1): 1-12.
14. de Leon JC. Rice that Filipinos grow and eat. PIDS discussion
paper series no. 2005-11. Philippine institute for development
studies: Makati, Philippines. Available at: http://dirp3.pids.
gov.ph/ris/dps/pidsdps0511.pdf 2005; Accessed 2015.
15. Romero GO, Rabara RC, Gergon EB, et al. Development
and utilization of the PhilRice Genebank. Philippine Science
Letter. 2011; 4(1): 24-32.
16. Rabara RC, Gergon EB, Romero GO, Nazareno ES, Newingham
MCV, Diaz CL. Manual on rice genetic resources conservation
and management. Philippine Rice Research Institute:
Nueva Ecija, Philippines, 2011.
17. Rabara RC, Ferrer MC, Newingham MCV, Diaz CL, Romero
GO. Phenotypic diversity in farmers’traditional rice varieties
in the Philippines. Agronomy. 2014; 4(2): 217-241. doi: 10.3390/
agronomy4020217
18. Vaughan DA, Lu BR, Tomooka N. The evolving story of rice
evolution. Plant Science. 2008; 174: 394-408. doi: 10.1016/j.
plantsci.2008.01.016
19. Biswal A, Kohli A. Cereal flag leaf adaptations for grain
yield under drought: knowledge status and gaps. Molecular
Breeding. 2013; 31: 749-766. doi: 10.1007/s11032-013-9847-7
20. Villegas-Pangga G. Indigenous knowledge systems and
organic farming technologies: Farmers’access to community
technological learning. Available at: http://satnetasia.org/sites/
default/files/9_Indigenous_knowledge_systems%2Borganic_
farming_tech-University_Philippines_LosBanos_paper.pdf
2013; Accessed 2015.
21. Ferguson AR. The need for characterisation and evaluation
of germplasm: Kiwifruit as an example. Euphytica. 2007;
154(3): 371-382. doi: 10.1007/s10681-006-9188-2
22. Hijmans RJ, Garrett KA, Huamán Z, Zhang DP, Schreuder
M, Bonierbale M. Assessing the geographic representativeness
of genebank collections: the case of Bolivian wild potatoes.
Conservation Biology. 14(6): 1755-1765. Available at: http://
www.diva-gis.org/docs/bias.pdf 2000
23. Hermann M. Progress report of the IBPGR research project
on the genetic resources of Andean tuber crops. AGP-IBPGR
report 89/2. International Board for Plant Genetic Resources,
Rome, 1988.
24. Von Bothmer R, Seberg O. Strategies for the collecting of
wild species. Collecting plant genetic diversity, technical guidelines.
CAB International: Wallingford, United Kingdom. 1995:
93-111.
25. Ollgaard B, Churchill SP, Balslev H, Forero E, Luteyn JL.
Diversity of Huperzia (Lycopodiaceae) in Neotropical montane
forests. Biodiversity and conservation of neotropical montane
forests. Proceedings of a symposium, New York Botanical Garden,
21-26 June 1993. New York Botanical Garden. 1995; 349-
358.
26. Schreinemachers P, Ebert AW, Wu MH. Costing the ex situ
conservation of plant genetic resources at AVRDC-the world
vegetable center. Genetic Resources and Crop Evolution. 2014;
61(4): 757-773. doi: 10.1007/s10722-013-0070-5
27. McCouch SR., McNally KL, Wang W, Hamilton RS. Genomics
of gene banks: a case study in rice. Am Jour of Botany.
2012; 99(2): 407-423. doi: 10.3732/ajb.1100385
28. Ebana K, Kojima Y, Fukuoka S, Nagamine T, Kawase M.
Development of mini core collection of Japanese rice landrace.
Breeding Science. 2008; 58: 281-291. doi: 10.1270/jsbbs.58.281
29. FAO (Food and Agriculture Organization). The second report
on the state of the world’s plant genetic resources for food
and agriculture. FAO, Rome, Italy. 2010
30. Nelson PT, Goodman MM. Evaluation of elite exotic maize
inbreds for use in temperate breeding. Crop Sci. 2008; 48: 85-92.
31. Visser B, Engels J. Setting objectives for genebanks. A guide
to effective management of germplasm collections. In: Engels
JMM, Visser L, eds. IPGRI Handbooks for Genebanks No. 6.
IPGRI, Rome, Italy, 2003.
Top
» Introduction Free
» Figures and Tables Free
» References Free
» Full Text Free
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Article History
Received: August 21st, 2015
Accepted: October 7th, 2015
Published: October 8th, 2015

Editor-in-Chief
Michael J. Gonzalez, PhD, CNS, FACN
Professor of Nutrition Program
School of Public Health Medical Sciences Campus
University of Puerto Rico
Gobernador Pinero, San Juan, 00921, Puerto Rico

Associate Editor
Yaning Sun, PhD
Translational Gerontology Branch
NIH Biomedical Research Center
251 Bayview Blvd., Suite 100
Baltimore, MD, 21224, USA

Associate Editor
Zheng Li, PhD
Food Science and Human Nutrition
Institute of Food and Agricultural Sciences
University of Florida, Gainesville, FL 32611, USA

Associate Editor
Cheryl Reifer, PhD, RD, LD
Interim VP, Scientific Affairs Consultant at Sprim Advanced Life Science
President at Cheryl J. Reifer, LLC
4601 Cape Charles Dr. Plano, TX 75024, USA
