The world collection is held by ICARDA; most of the other national collections hold some portion of subsets of this collection and vice versa (Table 7.2). ICARDA also holds the largest collection of the wild Lens accessions from 46 countries (Furman, Coyne, Redden, Sharma, & Vishnyakova, 2009; Table 7.3). It is difficult to determine exactly the overlap, duplication or redundancy due to the lack of consistent access to
databases, lack of cross-reference to other gene bank accession identification within databases (i.e. accession names/numbers) and lack of data per se (Potan, 2009; Tullu, Diederichsen, Suvorova, & Vandenberg, 2011). The Australian Temperate Field Crops Collection (ATFCC) database has made the most progress in cross-referencing by name/number identification across national gene banks including the world lentil col- lection at ICARDA and is available by request (Redden, personal communications at ATFCC). Fortunately, the world crop genetic resources community is addressing the database issue directly through efforts within the Consultative Group on International Agricultural Research (CGIAR) system, through Bioversity International, through conferences, particularly the conference series International Symposium on Genomics of Plant Genetic Resources and white papers under development by the Global Crop Diversity Trust (http://www.croptrust.org/). One white paper developed was the
Table 7.2 The World Ex Situ Lens Collection Held by the ICARDA with Significant Lens Germplasm with Other National Gene Bank Collections of 2000+ Accessions Institution Accessions Website
ICARDAa 10,822 http://www.icarda.org/
ECPGRb 4598 http://www.ecpgr.cgiar.org/germplasm_databases.html Indiac 7712 http://www.nbpgr.ernet.in/
ATFCCd 5254 http://www.dpi.vic.gov.au/ USDA ARSe 3187 http://www.ars-grin.gov/npgs/ Iranf 3000 http://en.spii.ir/seSPII/ Russian Federationg 2556 http://www.vir.nw.ru/
(modified from Tullu, Bett et al., 2011; Tullu, Diederichsen et al., 2011).
aInternational Center for Agricultural Research in the Dry Areas, Aleppo, Syria. bEuropean Cooperative Program for Plant Genetic Resources includes Russian Federation. cNational Bureau of Plant Genetic Resources (NBPGR), New Delhi, India.
dAustralian Temperate Field Crops Collection, Horsham, will be consolidated into the new Australian Grains Gene Bank,
Horsham, Victoria, Australia.
eUnited States Department of Agriculture, Agricultural Research Service, Pullman, WA, USA. fSeed and Plant Improvement Institute (SPII), Karaj, Iran.
gN.I. Vavilov All-Russian Scientific Research Institute of Plant Industry (VIR), St. Petersburg, Russia.
Table 7.3 Wild Lens Conserved Ex Situ with the World Collection Held by ICARDA and One National Gene Bank of USDA ARS NPGS
Taxon USDA ICARDA
Lens culinaris ssp. orientalis 92 268
Lens culinaris ssp. odemensis 8 65
Lens culinaris ssp. tomentosus 0 11
Lens ervoides 61 166
Lens lamottei 0 10
Lens nigricans 37 63
‘Global Strategy for the Ex Situ Conservation of Lentil (Lens Miller) (2008)’ which includes a goal to assemble passport data on major pulses, including lentil, from col- lections worldwide into a single database linked with geographical information sys- tem (GIS) data. While not the largest lentil collection by far, the USDA ARS stands out in the accessibility of its database and seed samples and will be used as an exam- ple of a national database in comparison with the world collection (Table 7.3). Recent collections include two plant explorations in Crimea and Ukraine. Diederichsen, Rozhkov, Korzhenevsky, and Boguslavsky (2012) collected genetic resources of crop wild relatives (CWR) including eight wild Lens species and Bockelman (1999) col- lected one each of L. ervoides and L. nigricans accessions.
7.4.2 In Situ Conservation
The number of accessions preserved ex situ from the regions of origin and diversity has been increasing. Seed has been collected from each taxon and used in further study to determine within-population diversity. This will help to establish the poten- tial of in situ conservation for wild Lens species (Ferguson & Robertson, 1996). Unfortunately, many areas of greatest interest for in situ conservation (e.g. Turkey and other Mediterranean countries) are suffering from rapid loss of invaluable genetic resources due to habitat destruction (Solh & Erskine, 1981). The relatively poor competitive ability and high palatability of Lens species, together with the fact that they occur in small disjunct populations, intensifies this threat (Ferguson et al., 1996). Important areas to target for in situ conservation include west Turkey for
L. nigricans, southeast Turkey, northwest Syria, south Syria and Jordan for L. culi-
naris ssp. orientalis, south Syria for L. culinaris ssp. odemensis and the coastal border region between Turkey and Syria stretching along the Syrian coast for
L. ervoides (Ferguson, Ford-Lloyd, Robertson, Maxted, & Newbury, 1998).
7.5 Germplasm Evaluation and Maintenance
Cultivated lentil experienced a genetic bottleneck with low amounts of molecular variation in the lentil germplasm collections (Alo et al., 2011; Alvarez, García, & Pérez de la Vega, 1997; Ferguson et al., 2000; Ford, Pang, & Taylor, 1997; Mayer & Soltis, 1994; Muench et al., 1991). Erskine, Sarker, and Ashraf (2011) used traits of flowering time and yield to reconstruct the genetic bottleneck of lentil into south Asia. Nonetheless, useful variation in cultivated lentil has led to significant breeding advances. Future genetic gains will be dependent on introgressing useful alleles from landraces and other wild Lens relatives for widening the genetic base of cultivated species. Lentil evaluation descriptors were published in 1985 by the International Board for Plant Genetic Resources (now Bioversity International) and ICARDA (IBPGR, 1985). Abiotic and biotic stress resistance screening are summarized in
Table 7.4. Several studies have been conducted and published on multilocational tri- als of landrace accessions for agronomic (descriptor) traits. Lentil core and compos- ite collections allow for the sampling of diverse lines and provide an efficient method
Table 7.4 Sources of Foreign Genes from the Landraces and Wild Relatives for Introgression into Lentil
Useful Trait(s) Wild Relative References Anthracnose
resistance
L. ervoides, L. lamottei,
L. nigricans
Tullu et al. (2006), Tullu, Banniza, Taran, Warkentin, and Vandenberg (2010),
Fiala, Tullu, Banniza, Séguin-Swartz, and Vandenberg (2009), Vail and Vandenberg (2011) and Vail, Strelioff, Tullu, and Vandenberg, (2012)
Ascochyta blight resistance
L. ervoides, L. culinaris ssp.
orientalis, L. odemensis,
L. nigricans, L. lamottei
Bayaa et al. (1994), Nguyen, Taylor, Brouwer, Pang, and Ford (2001) and
Tullu et al. (2006, 2010)
Colletotrichum truncatum
resistance
L. culinaris Buchwaldt, Anderson, Morrall, Gossen, and Bernier (2004) and Shaikh et al. (2012) Stemphylium blight L. ervoides, L. culinaris ssp. orientalis, L. tomentosus, L. nigricans, L. odemensis, L. lamottei
Podder, Banniza, and Vandenberg (2012)
Fusarium wilt resistance
L. culinaris ssp. orientalis,
L. ervoides
Bayaa et al. (1995), Gupta and Sharma (2006) and Mohammadi, Puralibaba, Goltapeh, Ahari, and Sardrood (2012)
Powdery mildew resistance
L. culinaris ssp. orientalis,
L. nigricans
Gupta and Sharma (2006)
Rust resistance L. culinaris ssp. orientalis,
L. ervoides, L. nigricans,
L. odemensis
Gupta and Sharma (2006)
Drought tolerance
L. odemensis, L. ervoides,
L. nigricans
Hamdi and Erskine (1996)
Cold tolerance L. culinaris ssp. orientalis Hamdi, Küsmenoĝlu, and Erskine (1996)
Heat tolerance L. culinaris Roy, Tarafdar, Das, and Kundagrami (2012)
Yield attributes L. culinaris ssp. orientalis Gupta and Sharma (2006)
Resistance to
Orobanche
L. culinaris, L. ervoides,
L. odemensis,
L. orientalis
Fernández-Aparicio, Sillero, Pérez- De-Luque, and Rubiales (2008) and
Fernández‐Aparicio, Sillero, and Rubiales (2009) Resistance to sitona weevils L. odemensis, L ervoides, L. nigricans, L. culinaris ssp. orientalis
El-Bouhssini, Sarker, Erskine, and Joubi (2008) Resistance to bruchid weevils L. culinaris ssp. orientalis, L. nigricans, L. lamottei Laserna-Ruiz, De-Los-Mozos-Pascual, Santana-Méridas, Sánchez-Vioque, and Rodríguez-Conde (2012)
for finding sources of new traits (Furman, 2006; Simon & Hannan, 1995). The USDA lentil core collection of 287 L. culinaris accessions was characterized for phe- nology, morphology, biomass and seed yields over two seasons (Tullu, Kusmenoglu, McPhee, & Muehlbauer, 2001). Thirty landraces of Pakistan were evaluated for flow- ering and yield components also over two seasons to determine diversity for breed- ing strategies (Tyagi & Khan, 2011). Morphological and phenological variation was also assessed in 310 accessions of the wild relatives of lentil (Ferguson & Robertson, 1999). ICARDA has established a composite collection of 1000 accessions to repre- sent genetic diversity and the agro-climatological range of lentil and this will be used for intensive phenotyping and genotyping purposes (Furman, 2006).
Lentil is a naturally self-pollinated species due to its cleistogamous flowers (Wilson, 1972) and usually has <0.8% natural cross pollination (Wilson & Law, 1972). Outcrossing in lentil depends on cultivar, location and year, and varies within cultivars (Horneburg, 2006). For regeneration and backup storage, bioversity recom- mends a base collection of accessions in long-term storage used for regeneration, an active collection in less stringent conditions accessible for distribution and a security backup collection at a different location (Engels & Visser, 2003). Similarly, a guide is published for regeneration guidelines of lentil (Sackville Hamilton & Chorlton, 1997). Lentil seed can be stored for relatively long periods of time at −18°C (Walters, Wheeler, & Grotenhuis, 2005). Seed handling conditions from harvest to storage temperature and relative humidity are critical components affecting seed lon- gevity (Walters, Wheeler, & Stanwood, 2004). Long-term storage temperatures are an important (neglected) factor given conventional seed bank temperatures (Li & Pritchard, 2009).