Ex Situ Conservation of Chili (Capsicum spp.)

TARUN HALDER and BISWAJIT GHOSH"

Plant Biotechnology Laboratory, Department of Botany, Ramakrishna Mission Vivekananda Centenary College, Rahara, Kolkata, India

'Corresponding author. E-mail: This email address is being protected from spam bots, you need Javascript enabled to view it

ABSTRACT

Plant genetic resources are essential to check the diminishing of genetic erosion and for development of improved high-yielding commercial varieties that are a better response against biotic and abiotic stresses as well as combat new climatic conditions. Chili is an important vegetable and cash crop around the world. The genus Capsicum is mainly cultivated for its nonpungent (sweet pepper), pungent, and ornamental values. It is rich in bioactive compounds, which contribute to the improvement of human health. For future agricultural development and improvement of the food security program, plant genetic resources must be conserved in the form of seeds, plants, tissues, etc. Biotechnology approach involving plant tissue culture is a powerful technique that can be an alternative to conventional breeding and advance germplasm improvement. Several teclmiques are applied for conservation of Capsicum that are more effective, like seed bank, greenhouse, tissue culture, in vitro conservation, cryopreservation, etc? For long-term ex situ conservation of disease-free materials, the only in vitro conservation method can be adopted, it reducing the growth rate of plant material and increasing subculture intervals. For prolonged conservation, ultralow temperature (cryopreservation) can be used in the contamination- free state of chili materials.

Some useful germplasm for continuous agricultural methods and diversity of breeding lines are lost due to the constant refinement activities, which are only focused on elite genotypes or germplasms and their proper conservation. This conservation method avoids the conservation of wild genotypes and wild crop-relatives that are veiy important for further improvement of crop cultivar. An effective and well-organized conservation system is required to support from different nations and a true continuation of this program needs an effective initiative for regular collection of plant genetic resource from wild and their good conservation management.

INTRODUCTION

Preservation of genetic diversity of a specific plant species or genetic stock is primarily required for germplasm conservation. Ex situ conservation is now an important mode for conservation of crop varieties and wild genetic resources because of its utility in future crop improvement. The words chili and chile basically come from people of Nahuatl, the Uto-Aztecan language family of central Mexico. Since 7500 BCE, the red peppers have been common in a part of the world populations’ diet. It is now assumed that chili was domesticated in Mexico more than 6000 years ago.

Bosland (1996) reported that chili was the first self-pollinating crop cultivated in Mexico and South America. Even at that time, the people of Central and South American countries believed the myth that capsicum plants acted as the god of war, used to counter magic and protection rituals. Sprinkled around the house, they were expected to clean the area of illegal demons and vampires; however, burning them laterally with garlic and other pungent spices were anticipated to fumigate and purify the house. Parenthetically this practice is also reputed to disperse vermin and insects.

The world center creates improved inbred and its germplasm accession lines resulting from its improvement breeding programs available for international use as global public crop materials (Keatinge et al., 2012). Globally, in most developing countries, chili researchers, in both public and private sectors, now use germplasms for better crop products. In Capsicum, a total of 8235 accessions have collected under AVRDC, which is the world’s largest accession center comprising about 11% of all crops and vegetable accessions maintained globally (Reddy et al., 2015). Out of the total collected accessions are 66% (C. annuum), 8% (C. frutescens), 6% (C. chinense), 5% (C. baccatum), and others (Lin et al., 2013).

BOX 17.1 Capsicum Genebank, Country and Collection

Genebank Institute code

Genebank Acronym

Country

Accessions No.

TWN001

AVRDC

Taiwan

7914

USA016

S9

USA

4698

MEX008

INIFAP

Mexico

4661

IND001

NBPGR

India

3835

BRA006

LAC

Brazil

2321

JPN003

NIAS

Japan

2271

PHL130

IPB-UPLB

Philippines

1880

TWN005

TSS-PDAF

Taiwan

1800

DEU146

IPK

Germany

1526

CHN004

BVRC

China

1394

Others (176)

Others

41,272

World

73,572

’Actual data (May 2011) from Asian Vegetable Genetic Resources Information System.

Capsicum is an important commercial vegetable and spice crop all over the world. Generally, 400 different capsicum varieties are found, but there are thought to be 38 species of Capsicum (Table 17.1), of which only 5-6 species are cultivated, major one is C. atmuum, C. frutescens, C. baccatum, and C. baccatum, etc. (Kothari et al., 2010; Ramchiary et al., 2014; Reddy et ah, 2015; Haque et al., 2016; Hegde et ah, 2017). Capsicum is rich in pharmaceutically high-valued bioactive compounds that contribute to the betterment of human health (McConnack, 2010) (Fig. 17.1).

Other than medicinal and nutritional reputation, breeders have improved agricultural practices of pepper, such as pungency, fruit shape, disease resistance, that is, biotic stress and abiotic stress tolerance, etc. (Lee et ah,

2016). For food security and sustainable agricultural development of the plant, genetic resources of wild genotypes and commercially less important cultivars are conserved in the form of plants, seeds, tissues, etc. (Babu et ah, 2012).

Due to the pressure of more and more production, all agricultural policymakers and scientists are concerned only on superior varieties that create a homogeneity, on the other hand, wild genotypes are gradually eroded due to lack of our interest but, at present, due to environmental problems, we try to collect genetically variant genotypes that are already missing. This standing action for the conservation of germplasm is essential at species, gene pool, or ecosystem level for successors (Frankel, 1975) It is a fact that a lot of useful genes in the landraces and genetic diversity of breeding lines have been lost due to the continuous breeding among high-yielding cultivars (Tang et al., 2010; Lee et al., 2016; Hedge et al., 2017). Ex- situ conservation is a safe and efficient approach to conserve chili genetic resources and to make the geimplasm readily available to breeders, plant biotechnologists, and other researchers. The duty of the plant breeder or genetic engineer is to create an improved variety with respect to their nutritional value, stress tolerance, as well as high-yielding cultivars. For ex situ conservation, different modes of preservation are adopted for chili from a traditional approach to modem methods (Fig. 17.2).

Medicinal importance of chili

FIGURE 17.1 Medicinal importance of chili.

FIELD GENE BANK

Physical facilities for maintaining collections of live plant materials under field conditions are called field gene bank. According to Plant Genetic Resources for Food and Agriculture, gene banks are assured in two activities (1) germplasm secure in the long term and (2) are made available for use by fanners, plant breeders, and researchers. Among all areas of plant genetic resources (PGR) activities, exchange of germplasm has become crucial for the formation of a legal framework to protect their biodiversity

S. No.

Species

Locality

1.

Capsicum, annuum L.

Southern USA. Mexico. Antilles, Belize. Panama. Costa Rica. Guatemala, Surinam. Venezuela. Colombia, Ecuador. Peru, northern and northeastern Brazil

2.

C. baccatum L.

Colombia. Peru, Bolivia, Paraguay, southern and southeastern Brazil, northern Argentina, Chile. Argentina. India

3.

C. buforum Hunz.

Brazil

4.

C. caballeroi M. Nee

Bolivia

5.

C. campylopodium Sendtn.

Brazil

6.

C. caidenasii Heiser & P. G. Sin.

Bolivia

7.

C. ceratocalyx M. Nee

Bolivia

8.

C. chacoense Hunz.

Southern Bolivia. Paraguay, northern and central Argentina

9.

C. chinense Jacq.

Cultivated in USA. Mexico. Central America. Ecuador. Peru, Bolivia, Brazil. Argentina, China. Japan. Thailand

10.

C. coccineum (Rusby) Hunz.

Peru. Bolivia

11.

C. coivutum (Hiern) Hunz.

Brazil

12.

C. dimorphum (Miers) Kuntze

Colombia. Ecuador

13.

C. dusend Bitter

South-East Brazil

14.

C. eximium Hunz.

Southern Bolivia, northern Argentina

15.

C. jlexuosum Sendtn.

Paraguay, southern and southeastern Brazil, northeastern Argentina

16.

C. fhburgense Bianch. & Barboza

Brazil

17.

C. fmtescens L.

USA, Mexico. Central and South America. Africa, India, China. Japan. Thailand

18.

C. galapagoense Hunz.

Ecuador

19.

C. geminifolium (Daumier) Hunz.

Colombia. Ecuador. Peru

S. No.

Species

Locality

20.

C. havanense Kuntli

Colombia

21.

C. hookehamtm (Miers) Kuntze

Southern Ecuador, northern Peru

22.

C. hunzikerianum Barboza & Biancli

Brazil

23.

C. lanceolatum (Greenm.) С. V. Morton & Standi

Mexico. Guatemala

24.

C. leptopodum (Dtmal) Kuntze

Brazil

25.

C. lycianthoides Bitter

Peru

26.

C. minutifloivm (Rusby) Hunz.

South America, Northern and Central America

27.

C. mirabile Mart, ex Sendtn.

Brazil

28.

C. panifolium Sendtn.

Colombia, Venezuela, northeastern Brazil

29.

C. pereirae Barboza & Biancli.

Brazil

30.

C. pubescens Ruiz & Pav.

Mexico, Central and South America

31.

C. ramosissimum Witasek

Africa. Madagascar, South Africa. Afghanistan

32.

C. recurvatum Witasek

Brazil

33.

C. rhomboideum (Dunal) Kuntze

Mexico. Guatemala. Honduras. Colombia. Venezuela. Ecuador. Peru

34.

C. schottianum Sendtn.

Brazil

35.

C. scolnikianum Hunz.

Ecuador

36.

C. spina-alba (Dunal) Kuntze

Africa

37,

C. stramoniifolium (Kuntli) Standi.

Peru

38.

C. villosum Sendtn.

Brazil

and interest of future needs for conservation of particular crop diversity and crop improvement (Nair et al., 2017).

Flowchart for documentation and conservation

FIGURE 17.2 Flowchart for documentation and conservation.

Diversity or variation of all biological species are essential and this biological diversity could be at three levels: Variation in genes and genotypes (genetic diversity), species richness (species diversity), and ecological diversity for communities of species. It must be recognized that only diversity can allow sustainability and can lead to development in several human activities, like social and economic systems to flourish, which can ensure to meet food security and avoiding the malnutritional problem in poorest communities of different countries (Shiva, 1994).

For more than two decades, there has been a growing awareness of the wholesome view of biodiversity, particularly agrodiversity, and conservation for sustainable use and development (Jacobsen et al., 2013). A very common but serious loss of plant genetic resources from natural disasters, such as floods, fires, snow, volcanoes, earthquakes, and hurricanes, is another important criterion for ensuring the physical safety of collections. Furthermore, physical security and potential of anthropogenic extortion, such as theft and vandalism, should be taken into consideration. The designing and location of a field gene bank should be considered to retain the characteristic feature of a particular genotype. Though conservation and utilization of genetic resources are well recognized, during the last decade, their importance has been further highlighted in two global conventions. The first CBD held at Rio (1992), Brazil, and second, at the International Technical Conference on the Conservation and Use of Plant Genetic Resources for Food and Agriculture (Iwanaga, 1994; FAO, 1996).

The 1992 and 1996 resolutions equally have recognized the authority of countries where the PGR accessible surrounded by their borders but the problem to conserve and use PGR rests with developing countries and stresses on the significance of impartial sharing of these resources and knowledge related to their proper exploitation. Among the 20 priority activities of the Global Plan of Action, network of PGR for food and agriculture is also included. Due to the highly specific nature of different environments, such domestication has resulted in many ‘ecospecific’ adaptations, which resulted in the formation of landraces, well-matched to local environments (Bennett et al., 1987).

Most of the chili cultivars grown are known to be susceptible to pest, insect, and some microbial disease. That is why there is a necessity to explore the possibility of relative tolerance and resistance of the cultivar’s cultures under restricted field conditions (Singh and Pandey, 2015, Samanta et al.,

2017). In a few cases, insect resistance and hybrid chili are also conserved in separate field places (Samanta et al., 2017).

 
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