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F. J. MUEHLBAUER ET AL.
VIII. Hybridization Methods
B. Environmental Conditions
C. Equipment Needed
D. Emasculation of the Female Flower
F. Other Considerations for Crossing
A. Germ Plasm Collections
B. Collection and Utilization of Wild Species
A. Qualitatively Inherited Traits
B. Quantitative Inheritance
XI. Interspecific Hybridization
XII. Methods Used for Lentil Breeding
A. Pure Line Selection
B. Bulk Population
C. Pedigree Selection
D. Single Seed Descent
E. The Backcross Method
XIII. Breeding Objectives
A. Seed and Straw Yields
C. Root Rot/Wilt Complex
G. Adaption to Mechanical Harvesting
H. Other Objectives
Since domestication in the Near East, lentil (Lens culinaris Medikus) has held
a prominent place in cropping sequences in semiarid regions of the world and has
provided an important source of dietary protein. Despite the great importance of
the lentil crop to local populations, the crop has often been relegated to marginal
areas where it is grown without the benefit of fertilization, herbicides to control
weeds, pest control chemicals, or irrigation. The crop nevertheless has remained
popular in those areas possibly because of tradition but more importantly because
lentil may be one of only a few crops that can be grown.
Research on improvement of the lentil crop has been minimal until the recent
establishment of the international agricultural research centers and particularly
PRODUCTION AND BREEDING OF LENTIL
the establishment of the International Center for Agricultural Research in the
Dry Areas (ICARDA) in 1978 and their mandate for lentil crop improvement.
Landraces of lentil and related wild species have been collected and are being
maintained at ICARDA, at national research centers, and at the US.Department
of Agriculture, Western Regional Plant Introduction Station at Pullman, Washington. The availability of germ plasm has been instrumental in the development of
improved cultivars that have become of increasing importance in the production
of the crop.
Oram and Agcaoili (1994) have pointed out a significant increase of lentil production throughout the world during the 1980s because of yield increases and
increases of area sown. The area sown to lentil has continued to increase in Canada, Turkey, and Australia. The lentil crop, including production practices, germ
plasm constraints to production, breeding, genetics, and uses, is reviewed and
Lentil is one of the principal food crops cultivated in the semiarid regions of
the world, particularly in the Indian subcontinent and in the dry areas of the
Middle East. The crop is a dietary mainstay in those areas and is mostly consumed
by local populations. Of the countries that produce lentil, India is the largest producer followed by Turkey, Canada, and Syria. Ethiopia and Morocco are also
major producers of lentil. Other countries of the Middle East such as Egypt, Jordan, Iraq, and Lebanon are major consumers of lentil but not major producers.
World production in the areas of major use has declined in recent years as a result
of a dramatic shift toward the production of cereals, with legume crops being
relegated to more marginal areas with poorer soils and limited rainfall. Another
major factor in the decline of lentil production in the Middle East, except for
Turkey, has been the high cost of labor for harvesting the crop. In most of
the countries of the Middle East, the crop is harvested almost entirely by hand
(Khayrallah, 1981; Haddad and Arabiat, 1985). Turkey, on the other hand, has
increased its production through partial and, in some areas, complete mechanization. Crop residues from lentil are valuable as livestock feed in many regions
where grazing is limited. In dryland farming systems, the lentil crop offers farmers
an alternative to cereal grains and it contributes to the nitrogen budget of infertile
soil by fixing dinitrogen in symbiosis with Rhizobium.
World production of lentil increased by 72% during the 1980s (Oram and
Agcaoili, 1994), representing an increase of 95 1,000 tons. This dramatic increase
of lentil production resulted from a 4% increase in area sown and an overall increase of 4% in yield per hectare. Production in 1990 was estimated at nearly
F. J. MUEHLBAUER ET AL.
2.3 million tons. Major increases in production have been recorded from Canada
and Turkey. Significant shifts in lentil production have taken place throughout the
last 25 years. For example, the area sown has declined sharply in Syria, Jordan,
Iraq, and Ethiopia.
Production in India, Pakistan, and Bangladesh has remained relatively constant,
even though the crop is harvested almost entirely by hand; however, labor is
readily available in those countries.
Average lentil yields have varied widely from a low of 660 kg ha ' in India to
over 2100 kg ha - I in Egypt (Oram and Agcaoili, 1994) where the crop is grown
under irrigation. Yields have averaged over 1000 and 800 kg ha-' in the United
States and Canada, respectively.
Lentil production has increased to more than 600,000 tons annually in Turkey
(Oram and Agcaoili, 1994) and nearly doubled between 1984 and 1990 (FAO,
1991). Turkey is now the world's largest lentil exporter. The increased production
was brought about by fallow replacement in cereal production systems where sufficient rainfall is received to permit annual cropping (AGikgoz et al. 1994).
Of the lentils produced in the United States, over 85% are exported; however,
there is an aggressive marketing program underway which is designed to increase
domestic usage. Chile and Argentina are also major exporters in the western hemisphere. Canada has recently become a significant producer of lentil, and of the
nearly 230,000 tons produced annually in that country (FAO, 1991), nearly all
are exported. Canada has very quickly become the world's second largest lentil
Lentil has been produced on a commercial basis in the Palouse region of the
United States since 1937 (Youngman, 1968). The Palouse region, located in eastern Washington and northern Idaho and characterized by loess-rolling hills with
elevations of up to 900 m, is the major production area in the United States. In
that region, the crop is most often grown in rotation with cereals where lentil offers
a needed alternative to break cereal disease cycles, provides a crop where grassy
weeds can be adequately controlled, and, through nitrogen fixation, reduces the
demand for nitrogen fertilizers.
III. ORIGIN, TAXONOMY, CYTOLOGY,
AND PLANT DESCRIPTION
Cultivated lentils originated in the Near East arc and Asia Minor (Zohary, 1972;
Williams et al., 1974; Ladizinsky, 1979a, 1993; Zohary and Hopf, 1988). Lens
culinaris ssp. orientalis (Boiss) Handel-Mazzeti, which closely resembles the cul-
PRODUCTION AND BREEDING OF LENTIL
Figure 1. Typical habitat of wild L. orienrulis.
tivated species L. culinaris, is widely accepted as the progenitor species. L. culinaris ssp. orientalis has an extended range and can be found throughout the Near
East and as far east as Afganistan. The species is found in rocky and stony habitats
with very little soil (Fig. 1) and in association with other annual legumes, such as
the medics, and annual grasses. The conclusion that the cultivated lentil originated
in the Near East arc from L. culinaris ssp. orientalis is based on discoveries of
carbonized remains of apparent cultivated lentils in the same region over which
L. culinaris ssp. orientalis is distributed. Such carbonized remains have appeared
in early Neolithic settlements that date back to 7000-6000 BC (Helbaek, 1959).
Evidence for the center of origin and domestication of lentil has been reviewed by
Ladizinsky (1979a, 1993).
Cultivated lentil ( L . culinaris) belongs to the genus Lens which is associated
with other genera of the Vicieae tribe (Kupicha, 1981). The Vicieae tribe comprises Lens, Vicia L., Pisum L., Lathyrus L., and Vavilovia A. Fed. Cicer L. had