Wild Lentils: Treasure of Novel Diversity

The cultivated lentil (Lens culinaris ssp.
culinaris) is an annual herbaceous selfpollinating true diploid (2n=2x=14) species
with an estimated genome size of 4063
Mbp/C (Arumuganathan and Earle, 1991).
The crop is one of the first domesticated
species originated from the Near East
center of origin (Zohary, 1999), and is
most preferred grain legume of the old
world (Smartt, 1990). It is an important
winter season legume species grown in
Mediterranean and semi-arid climates. It
is a valuable source of protein (22-25%)
and emerged as nutritious substitute for
meat. Besides high protein, it also provides
minerals (K, P, Fe and Zn), carbohydrates,
crude fiber and vitamins (folic acid,
pantothenic acid and vitamin B6
) for human
nutrition (Bhatty, 1988; Kumar et al., 2018).
The lentil seeds are also rich in lysine and
tryptophan amino acids (Erskine et al.,
1990). Lentils high nutritional value with
a low level of anti-nutritional factors and a
shorter cooking time than most of other
pulses, make it highly suitable for human
consumption (Sahi et al., 2000).
The genus Lens belongs to family Fabaceae
and a total of seven taxa have been
recognized including domesticated species as lentil gene pool. The other wild lentil
taxa includes L. culinaris ssp. odemensis
Ladizinsky; L. culinaris ssp. orientalis
(Boiss) Ponert; L. ervoides (Brign) Granade;
L. lamottei Czefr; L. nigricans (Bieb)
Godron; and L. tomentosus Ladizinsky.
As far as compatibility relationships of
wild lentil taxa are concerned, L. culinaris
subsp. orientalis is readily crossable with
cultivated lentil (Robertson and Erskine,
1997) and considered as immediate
progenitor of domesticated species
(Barulina, 1930; Mayer and Soltis, 1994).
Globally, lentil stands in sixth position in
production among important pulses after
common bean, pea, chickpea, faba bean
and cowpea (FAO, 2018). However, the
world lentil production contributed 6% of
total dry pulse production during 2010-
2015 with an average productivity of 926
kg/ha. India is the largest lentil producer in
the world followed by Canada and Turkey,
which collectively contributed to 66% of
total world lentil production (FAO STAT,
2018). An average lentil grain yield in Asia
is 817 kg/ha, which is far below the world
average of 926 kg/ha. Lentil, despite its
significant role in human food, animal
feed and different cropping systems in the
Indian sub-continent, West Asia, Ethiopia,
North Africa and parts of Southern Europe,
Oceania and North America, has remained
under-exploited and researched crop until
recently. Further, modern lentil cultivars
have some eliteness over traditional ones in
terms of their good yielding ability, disease
and pests’ resistance, and high nutritional
value. If we look into the contribution of top
donors for developing high yielding varieties
of lentil, a small number of genotypes have
contributed significantly to the breeding
of majority of improved cultivars through
pure line and mass selection following
hybridization between lines adapted to
specific environmental conditions. Among
different accounts across lentil growing
regions of India, the pedigree analysis
of 35 released lentil cultivars has been
traced back to only 22 ancestors and the
top ten contributed 30% to the genetic
base of released cultivars (Kumar et al.,
2003). This narrow gene flow situation
could lead to the crop vulnerability to pest
and disease epidemics and unpredictable
climatic factors limiting progress towards
enhancing lentil production. Furthermore,
due to lentil cultivation on marginal lands
in most of developing countries including
India, its narrow genetic diversity makes
it more vulnerable to several biotic and
abiotic stresses leading to loss of yield
and nutritionally contributing traits of
interest. Being potential to be used as a
staple crop in many regions of world and
to meet the nutritious dietary requirements
of growing human population through
biofortification, it requires the consolidated
efforts to enhance the gene pool of
existing lentil varieties. Therefore, there is
an immediate need to widen the genetic
base of domesticated lentil cultivars by
introgression of diverse gene sources,
which are currently available in distantly
related wild Lens taxa. To synthesize the
new gene pool and maximize gains from the selection, it is therefore imperative to
accumulate favorable genes and alleles
from unadapted germplasm into the
backgrounds of cultivated germplasm.