Horsegram

Abstract

Horse gram is a pulse and fodder crop native to Southeast Asia and tropical Africa. India is the only country cultivating horse gram on a large acreage, where it is being used for human food. It is a versatile crop and can be grown from near sea level to 1800. m. It is a drought-tolerant crop plant and can be grown successfully with low rainfall. Global efforts to conserve the horse gram germplasm are lacking, as the crop does not attract much notice. The US Department of Agriculture (USDA) Germplasm Resources Information Network (GRIN) conserved only 35 accessions of Macrotyloma uniflorum in its gene bank. Protabase (Plant Resources of Tropical Africa Database), responsible for germplasm conservation for African countries, has only 21 accessions in the National Gene Bank of Kenya. Australian Tropical Crops and Forages Genetic Resources Centre, Biloela, Queensland has 38 accessions of horse gram. In India, the National Bureau of Plant Genetic Resources (NBPGR), New Delhi, is a nodal agency for the collection, conservation and documentation of horse gram germplasm; a total of 1627 accessions of horse gram are conserved in its gene bank. About 1161 accessions were systematically characterized and evaluated during 1999-2004 in different research institutions in India. No information on genomic resources is available for horse gram. However, the genetic information available for much researched related legume species could be useful in linkage map construction and for tagging and mapping of useful genes.

Full text

Genetic and Genomic Resources of Grain Legume Improvement. DOI:
© 2013 Elsevier Inc. All rights reserved.2013
http://dx.doi.org/10.1016/B978-0-12-397935-3.00012-8
Horsegram
R.K. Chahota1, T.R. Sharma1, S.K. Sharma1,
Naresh Kumar1 and J.C. Rana2
1Department of Agricultural Biotechnology, CSK Himachal Pradesh
Agricultural University, Palampur, Himachal Pradesh, India, 2NBPGR,
Regional Research Station, Phagli, Shimla, India
12
12.1 Introduction
Horsegram (Macrotyloma uniflorum (Lam.) Verdcourt (Syn., Dolichos uniflorus
Lam., Dolichos biflorus auct. non L.)) is a pulse and fodder crop native to Southeast
Asia and tropical Africa, but the centre of origin of cultivated species is consid-
ered to be southern India (Vavilov, 1951; Zohary, 1970). The name Macrotyloma is
derived from the Greek words makros meaning large, tylos meaning knob and loma
meaning margin, in reference to knobby statures on the pods (Blumenthal & Staples,
1993). It is a true diploid having chromosome number 2n=2x=20. It is cultivated in
India, Myanmar, Nepal, Malaysia, Mauritius and Sri Lanka for food purposes and
in Australia and Africa primarily for fodder purposes (Asha etal., 2006). The lim-
ited use of dry seeds of horsegram is due to its poor cooking quality. However, it
is consumed as soups and sprouts in many parts of India (Sudha, Mushtari Begum,
Shambulingappa, & Babu, 1995). Owing to its medicinal importance and its capabil-
ity to thrive under drought-like conditions, the US National Academy of Sciences
has identified this legume as a potential food source for the future (National
Academy of Sciences, 1978). India is the only country cultivating horsegram on a
large acreage, where it is used as human food. However, horsegram is a versatile
crop and can be grown from near sea level to 1800 m. It is highly suitable for rain-
fed and marginal agriculture but does not tolerate frost and waterlogging. It is a
drought-tolerant plant and can be grown with rainfall as low as 380 mm. Leaf dis-
eases and root rot are major production constraints in high rainfall areas. Being a
leguminous crop, it adds nitrogen to the soils where it grows, thus improving the soil
fertility. The protein content in cultivated horsegram is reported to be 16.9–30.4%
(Patel, Dabas, Sapra, & Mandal, 1995). It also has high lysine content, an essen-
tial amino acid (Gopalan, Ramashastri, & Balasubramanyan, 1989). Horsegram is
also rich in phosphorus, iron and vitamins such as carotene, thiamine, riboflavin,
niacin and vitamin C (Sodani, Paliwal, & Jain, 2004). It is known to contain many
medicinal and therapeutic benefits, although many of them are yet to be proven

Genetic and Genomic Resources of Grain Legume Improvement294
scientifically. It can be an ayurvedic medicine, used to treat edema, piles, renal
stones, and so on. It has polyphenols that have high antioxidant properties, molyb-
denum that regulates calcium intake and iron that helps in transporting oxygen to
cells and forms part of haemoglobin in blood (Murthy, Devaraj, Anitha, & Tejavathi,
2012; Ramesh, Rehman, Prabhakar, Vijay Avin, & Aditya, 2011). Horsegram is rich
source of Haemagglutinin, which is an agent or substance responsible for red blood
cells and agglutinate. Chaitanya etal. (2010) proved that the seeds of M. uniflorum
are endowed with significant antiurolithiatic activity. Certain tests have proven that
lipids extracted from horsegram are known to heal rats with peptic ulcers (Jayaraj,
Tovey, Lewin, & Clark, 2000). With the continuously expanding need for suitable
cultivar development, there is an urgent need for systematic collection, evaluation
and utilization of genetic resources for both the present and posterity.
12.2 Origin, Distribution, Diversity and Taxonomy
The origin of horsegram is not clearly mentioned in the literature. Though wild mem-
bers of M. uniflorum exist in both Africa and India (Ve rd c o u r t , 1 9 71 ), its centre of ori-
gin as cultivated plant is regarded as India (Purseglove, 1974; Smartt, 1985; Vavilov,
1951; Zohary, 1970). Arora and Chandel (1972) have been more specific in arguing that
the primary centre of origin and use of M. uniflorum var. uniflorum as a cultivated plant
is southwestern India. Mehra and Magoon (1974), on the other hand, suggest that M.
uniflorum has both African and Indian gene centres. The other varieties, var. stenocar-
pum and var. verucosum, are basically of African origin, although a wild or long natu-
ralized form is found in northeastern Australia (Bailey, 1900). The region of maximum
genetic diversity is considered to be in the Old World tropics, especially the southern
part of India and the Himalayas (Zeven and de Wet, 1982). But some studies consider it
as a plant native to African countries. It was probably domesticated in India, where its
cultivation is known since prehistoric times and it is still an important cultivated crop.
Nowadays horsegram is cultivated as a low-grade pulse crop in many Southeast Asian
countries, such as India, Bangladesh, Myanmar, Sri Lanka and Bhutan. It is also grown
as a forage and green manure in many tropical countries, especially in Australia and
Africa, but it is unclear to what extent it is currently grown. The wild relatives of horse-
gram are reported mainly in Australia, Papua New Guinea, Africa and India. There is
no report that horsegram is cultivated as a pulse crop, in central, eastern and southern
Africa where it occurs wild. (Blumenthal, O’Rourke, Hidler & Williams, 1989).
Horsegram is a slender, twining annual herb with cylindrical tomentose stems. As
a pure crop it cannot stand due to its weak stem and forms a dense mat of 30–60 cm
height, but in association with cereals as a mixed crop it may climb on the com-
panion species to a height of 60–110 cm. It has trifoliate leaves, 7–10 mm long
persistent stipules and 3–7 cm long petiole. Leaflets are ovate, rounded at base, acute
or slightly acuminate, commonly 3.5–7.5 cm long, 2–4 cm broad, length and breadth
ratio of 1.5–2.5. Flowers are short, sessile or subsessile10–12 mm long, two- to four-
flowered axillary racemes, greenish yellow with a vinous spot on the standard. Calyx
is tomentose with 2–3 mm long tube, and the lobes are lanceolate setaceous, 3–8 mm

Horsegram 295
long. Standard is oblong, slightly emarginate at the summit, 9–10.5 mm long,
7–8 mm broad, with two linear appendages about 5 mm long, wings 8–9.5 mm long
as long as the keel. Ovary is appressed with dense white hairs, style attenuate and
stigma surrounded by a ring of short dense hairs. Pods are stipitate, slightly curved,
tomentose, 4.5–6 cm long and about 6 mm broad. Seeds are usually six or seven per
pod, 6–8 mm long, 4–5 mm broad, pale fawn, sometimes with faint mottles or with
small scattered black spots and hilum placed centrally (Purseglove, 1974).
Initially horsegram was included in the genus Dolichos by Linnaeus but Verdcourt
(1980) reorganized the different species formerly assigned to Dolichos and assigned
the genus Macrotyloma to horsegram. The style, standard and pollen characteristics
distinguish Macrotyloma from Dolichos (Verdcourt, 1970). Most of the wild species
of the genus are restricted to Africa but some wild species have also been reported
in Asia and Australia. M. uniflorum is the only cultivated species grown in the
Indian subcontinent. The horsegram plant belongs to the kingdom Plantae, subking-
dom Tracheobionta, division Magnoliophyta and class Magnoliopsida. The genus
Macrotyloma (Wight & Arn.) Verdc. – Macrotyloma of family Fabaceae – consists
of about 25 wild species having the chromosome numbers 2n=2x=20 and 2n=2x=22
(Allen, O.N. & Allen, E.K. 1981; Lackey, 1981).
Within M. uniflorum, four varieties have been distinguished:
1. var. uniflorum: pods 6–8 mm wide; wild in southern Asia and Namibia, widely cultivated in
the tropics as a cover and forage crop.
2. var. stenocarpum (Brenan) Verdc.: pods 4–5.5 mm wide; shortly stiped and with more or
less smooth margins, leaflets pubescent; occurring in central, eastern and southern Africa
and in India, up to 1700 m altitude in grassland, bushland and thicket, often on sandy soils
and in disturbed locations; cultivated in Australia and California (the United States).
3. var. verrucosum Verdc.: pods 4–5.5 mm wide; distinctly stiped and with obscurely to mark-
edly warted margins, leaflets pubescent; occurring in eastern and southern Africa up to
550 m altitude in grassland and thicket.
4. var. benadirianum (Chiov.) Verdc.: pods 4–5.5 mm wide; shortly stiped and with slightly
warted margins, leaflets densely velvety; occurring in East Africa (Somalia, Kenya) at sea
level on sand dunes and thin soils on coral rag.
The geographical distribution of different species is provided in Tab l e 1 2. 1. It effec-
tively nodulates with nitrogen-fixing bacteria of the Bradyrhizobium group (Brink, 2006).
12.3 Erosion of Genetic Diversity from the
Traditional Areas
The quest for increasing food production and the ensuing success achieved in major
crops has increased the thrust and expectations to repeat the success in other minor
crops. Variability refers to heterogeneity of alleles and genotypes with their atten-
dant morphotypes and phenotypes. Genetic erosion implies that disappearance of
genetic variability in a population is altered so that the net change in diversity is
negative. Considerable genetic erosion started in the early 1960s due to changes in

Genetic and Genomic Resources of Grain Legume Improvement296
cropping pattern and induction of new crops in the Indian farming system. However,
population growth, urbanization, developmental pressures on the land resources,
deforestation, changes in land use patterns and natural disasters are contributing to
considerable habitat fragmentation and destruction of the crops and their wild rela-
tives. Horsegram is a neglected crop cultivated by poor and marginal farmers in
tribal localities and drought-prone areas of India (Jansen, 1989). There are no con-
certed efforts for varietal developments reported from any part of the world, bar-
ring some isolated efforts in a few research institutions in India. Therefore, genetic
erosion is not attributable in this case to the diffusion of high-yielding varieties to
replace the landraces. Rather, the main cause of genetic is the cultivation of commer-
cial crops in the horsegram–growing areas.
12.4 Status of Germplasm Resources Conservation
Horsegram is an important pulse crop of Indian sub-continent; therefore, the efforts
to conserve the germplasm at global level are also lacking. Therefore, most of the
Table 12.1 Geographical Distribution of Macrotyloma Species
S. No. Species Name Area of Distribution
1Macrotyloma africanum (Wilczek) Verdc. Africa
2Macrotyloma axillare (E.Mey.) Verdc. Africa and Australia
3Macrotyloma bieense (Torre) Verdc. Africa
4Macrotyloma biflorum (Schum. & Thonn.) Hepper Africa
5Macrotyloma brevicaule (Baker) Verdc. Africa
6Macrotyloma ciliatum (Willd.) Verdc. Asia and Africa
7Macrotyloma coddii Verdc. Africa
8Macrotyloma daltonii (Webb) Verdc. Africa
9Macrotyloma decipiens Verdc. Africa
10 Macrotyloma densiflorum (Baker) Verdc. Africa
11 Macrotyloma dewildemanianum (Wilczek) Verdc. Africa
12 Macrotyloma ellipticum (R.E.Fr.) Verdc. Africa
13 Macrotyloma fimbriatum (Harms) Verdc. Africa
14 Macrotyloma geocarpum (Harms) Marechal &
Baudet
Africa
15 Macrotyloma hockii (De Wild.) Verdc. Africa
16 Macrotyloma kasaiense (R. Wilczek) Verdc. Africa
17 Macrotyloma maranguense (Taub.) Verdc. Africa
18 Macrotyloma oliganthum (Brenan) Verdc. Africa
19 Macrotyloma prostratum Verdc. Africa
20 Macrotyloma rupestre (Baker) Verdc. Africa
21 Macrotyloma schweinfurthii Verdc. Africa
22 Macrotyloma stenophyllum (Harms) Verdc. Africa
23 Macrotyloma stipulosum (Baker) Verdc. Africa
24 Macrotyloma tenuiflorum (Micheli) Verdc. Africa
25 Macrotyloma uniflorum (Lam.) Verdc. Asia, Africa and Australia

Horsegram 297
conservation work was undertaken by Indian Institutes. The Germplasm Resources
Information Network (GRIN) of the US Department of Agriculture (USDA) has
conserved only 35 accessions of horsegram in its gene bank. Protabase, responsible
for germplasm conservation for African countries, has 21 accessions at the National
Gene Bank of Kenya, Crop Plant Genetic Resources Centre, Kenya Agricultural
Research Institute (KARI), Kikuyu, Kenya. The Australian Tropical Crops and
Forages Genetic Resources Centre, Biloela, Queensland has 38 accessions of horseg-
ram germplasm (Brink, 2006). Only the National Bureau of Plant Genetic Resources
(NBPGR) in New Delhi has a systematic collection of this important legume.
The efforts to collect and conserve the horsegram germplasm started way back in
the 1970s with the inception of the PL480 scheme (a scheme under collaboration
between Indian Council of Agricultural Research (ICAR) and the USDA project on
food security in Haiti, using Public Law 480), and since then germplasm has been
collected from almost all the horsegram–growing areas. Under different exploration
and collection programmes, a total of 1627 accessions of horsegram have been col-
lected and maintained at different satellite stations of NBPGR.
12.5 Germplasm Evaluation and Maintenance
Horsegram is being treated as a orphan crop therefore much attention has not been
paid to the systematic evaluation of germplasm, except maintaining it in the gene
banks. There are only a limited number of accessions conserved in the gene banks
worldwide. Ex situ conservation by different countries is given in Table 12.2. In
India, a total of 1627 accessions of horsegram are conserved in the national gene
bank, and out of these 1161 accessions were characterized during 1999–2004.
Latha (2006) made some observations while studying on agro-morphological traits
in Indian Dolichos germplasm that yield and yield component traits in general
showed that all promising lines with higher seed yield are of long duration type.
The seed yield per plant ranged from 0.22 to 7.31 g in short duration type, from
0.27 to 7.07 g in medium duration and from 0.21 to 11.86 g in long duration type.
Rana (2010) also observed variability in qualitative characteristics and revealed
that growth habit ranged from semi-erect to vine types, leafiness between sparse
and abundant, leaf pubescence from puberulant to densely pubescent and stem
Table 12.2 Ex Situ Conservation at Different Gene Banks of the World
S. No. Country Name of the Organization Accessions
1. India National Bureau of Plant Genetic Resources,
New Delhi
1627
2 The United States Germplasm Resources Information Network
of US Department of Agriculture
35
3 Australia Tropical Crops and Forages Genetic
Resources Centre, Biloela, Queensland
38
4 Kenya National Gene Bank of Kenya, Crop Plant
Genetic Resources Centre, KARI, Kikuyu
21

Genetic and Genomic Resources of Grain Legume Improvement298
colour between green and purple. However, range in variability was maximum in
pod and seed colour. Mature pod colour varied from straw, tan, cream, light brown,
brown, dark brown to brownish black. The plant height ranged from 17 to 145 cm
and primary branches per plant varied from 1.0 to 9.8 in number. Other yield
component traits such as pods per plant (4–148), pod length (3.07–6.17 cm), 100-
seed weight (0.92–4.10 g) and biological yield (0.21–11.86 g) revealed variabil-
ity. NBPGR has published a catalogue with details of 11 economically important
traits of 1426 accessions. During the Kharif (autumn) of 1984–1990, about 506
accessions at New Delhi and 920 accessions at NBPGR satellite research station
Akola were characterized and documented on the basis of evaluation data for vari-
ous qualitative and quantitative traits (Patel etal., Dabas, Sapra & Mandal, 1995).
The Vivekanand Parvartiya Krishi Anusandhan Sansthan (VPKAS), Almora, has
evaluated 10 lines for agro-morphological traits (Mahajan etal., 2007). Chahota,
Sharma, Dhiman, and Kishore (2005) evaluated 63 horsegram accessions pro-
cured from NBPGR, Phagli, Shimla for 12 agro-morphologic characters at CSK
Himachal Pradesh Agricultural University, Palampur. Kulkarni and Mogle (2011)
and Kulkarni (2010) evaluated 22 germplasm lines for different agronomic traits
and identified five high-yielding genotypes. Sudha etal. (1995) and Subba Rao
and Sampath (1979) evaluated horsegram lines for various nutritional and anti-
nutritional factors (Table 12.3). An attempt was made by Prakash, Channayya
Hiremath, Devarnavdgi & Salimath (2010) to assess the genetic divergence among
100 lines collected from different parts of Karnataka, using Mahalanobis D2
statistics. D2 is the distance between the different clusters having lines. In addi-
tion, considerable numbers of studies have been conducted on various aspects of
the crop by several researchers (Dobhal & Rana, 1994a, 1994b; Jayan & Maya,
2001; Joshi, Chikkadevaiah, & Shashidhas, 1994; Lad, Chavan, & Dumbre, 1999;
Patil, Deshmukh, & Singh, 1994; Savithriamma, Shambulingappa, & Rao, 1990;
Nagaraja, Nehru, & Manjunath, 1999; Sharma, 1995; Tripathi, 1999).
Table 12.3 Evaluation of Germplasm by Different Institutes for Agro-Morphological Traits
S. No. Name of the Institute Number of
Germplasm
Accessions
Evaluated
Year of
Evaluation
References
1 National Bureau of Plant
Genetic Resources,
New Delhi, India
1426 1984–1990 Patel etal. (1995)
2 NBPGR, New Delhi, India 22 2005 and 2006 Latha, (2006)
3 Parvartiya Krishi Anusdhan
Kendra Almora, India
10 2007 Mahajan etal.
(2007)
4 Himachal Pradesh Agricultural
University, Palampur, India
63 2005 Chahota etal.
(2005)
5 Commerce and Science
College Jalna, India
22 2011 Kulkarni (2010)

Horsegram 299
12.6 Use of Germplasm in Crop Improvement
New plant resources need to be exploited in order to meet the growing needs of human
society, which incidentally has depended on only a small portion of plant wealth.
Accordingly, many of underutilized plants have the potential for improving agriculture
in various ways and have great potential for exploitation in view of the value of their
economic products (Bhag & Joshi, 1991). Although a lot of germplasm has been col-
lected from different parts of the world and conserved in the national gene banks of
different countries, very little effort has been made to improve this plant as a commer-
cial crop. The lack of efforts both at institutional and governmental levels has under-
mined the importance of this crop. The evaluation and documentation of germplasm
have not been updated in many countries, so the utilization of germplasm could not
be taken up by the concerned breeders. In India, there are about 1800 accessions of
horsegram germplasm, of which only 912 lines have been evaluated and documented.
The genetic improvement of horsegram has been undertaken at just a few institutions
in India, but no improvement programme is in place at the global level.
In India, the cultivars released for cultivation are region specific and do not hold
promise for commercial agriculture, as the plant types contain many weedy traits,
such as twining and indeterminate growth habit, asynchronous and delayed maturity
and photosensitivity. Sufficient diversity is available for different traits as revealed
by germplasm evaluation data, but effort are lacking to develop ideal cultivars or to
introgress desirable traits scattered in different genotypes. Hybridization studies con-
ducted between photosensitive and day neutral varieties with black and brown col-
oured seeds revealed that photoperiod response is a qualitative trait that is controlled
by at least two genes. In case of inheritance of seed colour, the black seed colour
was observed to be dominant over brown. Two genes in polymeric gene action were
found to control seed colour (Sreenivasan, 2003). Most of the horsegram varieties
released for cultivation in different states in India originated from the local germ-
plasm following their effective and specific evaluation. The varieties developed in
different states (Table 12.4) include BR 5, BR 10 and Madhu from Bihar; HPK-2
and HPK-4 from Himachal Pradesh; PDM 1 and VZM 1 from Andhra Pradesh;
Table 12.4 Improved Varieties Released by Different States in India for Cultivation
S. No. Variety Place of Release
1 BR 5, BR 10 and Madhu Bihar
2 HPK-4 and VLG 1 Himachal Pradesh
3 PDM 1 and VZM 1 Andhra Pradesh
4 K82 and Birsa Kulthi Jharkhand
5 S27, S8, S39 and S1264 Orissa
6 Co-1, 35-5-122 and 35-5-123 Tamil Nadu
7 Hebbal Hurali 2, PHG 9 and KBH 1 Karnataka
8 Maru Kulthi, KS 2, AK 21 and AK 42 Rajasthan
9 VLG 1 Uttarakhand

Genetic and Genomic Resources of Grain Legume Improvement300
K82 and Birsa Kulthi from Jharkhand; S27, S8, S39 and S1264 for Orissa; Co-1,
35-5-122 and 35-5-123 from Tamil Nadu; Hebbal Hurali 2, PHG 9 and KBH 1 from
Karnataka; Maru Kulthi, KS 2, AK 21 and AK 42 from Rajasthan and VLG 1 from
Uttarakhand. Some of the improved varieties developed through single plant selec-
tion from the bulk collected included Co-1. No 35-5-122 and 123. Hebbal Hurali 1
and 2 were developed by the single plant selection (Kumar, 2005).
The nonavailability of important traits in the germplasm has encouraged many
workers to induce desirable traits by using gamma radiation and chemical mutants.
Gupta, Sharma, and Rathore (1994) induced variability for seed yield per plant,
biological yield per plant, pods per plant, pod length, seeds per pods and 100-seed
weight. Jamadagani and Birari (1996) developed three photo-insensitive mutants
by irradiating a photosensitive variety Dapali-1 with 20 kR. Ramakanth, Setharama,
and Patil (1979) attempted to induce mutation following treatment with five doses
of gamma rays. Chahota (2009) treated HPKC-2, a promising line, with a 25-kR
dose of gamma radiation and succeeded in inducing important agronomic traits in
horsegram. Wild forms of horsegram have also been reported in the Western Ghats,
especially in the wildlife sanctuaries. Macrotyloma ciliatum (Willd.) Verdc. is found
in Tamil Nadu (Mathew, 1983; Nair & Henry, 1983) and Andhra Pradesh (Pullaiah
& Chennaiah, 1997). Macrotyloma sar-garhwalensis is a wild relative of horsegram
found in the Central Himalayas of India (Gaur & Dangwal, 1997). It is a non-twining
annual herb with a high protein content of 38.35%, which can be utilized in the
breeding programmes for the improvement of protein content (Negi, Yadav, Mandal
& Bhandari, 2002). Macrotyloma axillare and M. africanum, the two other species of
this genus, have also shown potential as forage plants.
12.7 Germplasm Enhancement Through Wide Crosses
Horsegram is cultivated as a pulse crop only in the Indian subcontinent, whereas in
rest of the world, it is cultivated as a feed and fodder crop for animals. In pastures and
grasslands broadcasting of seeds is done to improve the grass quality. The major bot-
tleneck in the improvement of this crop is the lack of variability at the morphological
as well as molecular level. Therefore, wide hybridization could be a useful tool to cre-
ate additional variability for broadening its base. Though the genus Macrotyloma con-
sists of more than 25 species, there is no report regarding the evaluation of these wild
species for desirable traits. Morris (2008) compared M. uniflorum with M. axillare
and described a set of descriptors to differentiate these species. Evaluation of few
wild species of Macrotyloma has been undertaken at the CSK, Himachal Pradesh
Agricultural University, Palampur, India, to initiate a systematic hybridization pro-
gramme involving cultivated and wild species to transfer desirable traits from M.
axillare and Macrotyloma sar-garhwalensis to cultivated background. M. axillare
has many desirable traits such as high number of pods per plant, high seed yield
per plant and tolerance to cold and drought conditions (Staples, 1966, 1982). The
cultivated species of M. uniflorum is infected by a number of diseases, particularly
in high rainfall areas, such as Anthracnose, Cercospora leaf spot, Fusarium wilt,

Horsegram 301
rust, Pellicularia root rot and Aschochyta blight. Though the M. axillare is reported
to have resistance against many diseases hybridization between M. uniflorum and
M. axilare resulted in juvenile flowering in the first year of F1 plant, hence prolong-
ing the breeding process.
12.8 Horsegram Genomic Resources
The horsegram plant is considered unsuitable for commercial cultivation due to
the presence of many undesirable traits, such as longer days to maturity accompa-
nied by asynchrony, photosensitivity and indeterminate growth habit. However,
some work on the development of suitable ideotype is being conducted at CSK,
Himachal Pradesh Agricultural University, Palampur since 1995. Various breeding
techniques are being used to improve the plant type. Furthermore, it was felt that
before embarking on a breeding programme, the information on genetics of different
traits of interest is also an important aspect to combine important characters in the
well-adapted genetic backgrounds. The lack of genomic information in M. uniflorum
in particular and Macrotyloma genus in general is another hurdle for its systematic
breeding.
The legume family has been divided into three subfamilies, namely Casalpinieae,
Mimosoideae and Papilionoideae. Most of the economically important legumes are
members of the monophylotic subfamily paplionoideae, which is further divided
into four clades; clade phaseoloids have important warm-season legumes such as
Glycine, Phaseolus, Vigna, Cajanus and Macrotyloma species (Doyle & Luckow,
2003; Gept etal., 2005). There is complete genomic information available for the
two model legumes, Medicago truncatum and Arabidopsis, but that may not be very
useful in horsegram due to its distance from the warm-season grain legumes, as they
are in another clade. The recently sequenced Cajanus cajan genome can act as the
model plant for these orphaned warm-season legume crops. Therefore, sequence
information available in C. cajan can be crucial in understanding comparative
genomics of horsegram. Marker resources can also be used for constructing link-
age maps and identifying genomic regions linked to traits of agronomic value. Such
cross-species genetic information may be very important for ‘orphan crops’ such
as horsegram that have limited or no genomic resources available. Intron-targeted
amplified polymorphism (ITAP) markers among various legumes have a very high
degree of transferability rate and have been used to prepare linkage maps of Lupinus
albus (Phan, Ellwood, Adhikari, Nelson, & Oliver, 2006). Similarly a consensus
genetic map of cowpea has been developed from the genetic information available in
Glycine and Phaseolus species (Wellington etal., 2009). Some preliminary work in
this direction has been initiated at CSK, Himachal Pradesh Agricultural University,
Palampur to study the transferability of genomic Simple Sequnce Repeats (SSR)
markers of related legume species to prepare a framework genetic linkage map of
horsegram. This map will help to initiate a scientific breeding programme or marker-
assisted selection to develop improved plant types of horsegram.

Genetic and Genomic Resources of Grain Legume Improvement302
12.9 Conclusions
Horsegram is an important pulse crop of the Indian subcontinent; therefore, collec-
tion and systematic evaluation work on the germplasm are confined to India only. A
total of 1721 accessions of horsegram are being conserved in different gene banks
around the world. Of these collections, about 95% are conserved in the NBPGR,
New Delhi, and its regional research station. Regional Reserch Station of NBPGR,
Thrissur, Kerala, has been designated as the active site for the conservation and eval-
uation of horsegram germplasm amassed in Indian gene banks. All these accessions
need proper characterization and evaluation to enable their exploitation in a horseg-
ram breeding programme. Molecular markers provide precise information on genetic
diversity and help in more rapid breeding gain when it used in Markers Assisted
Selection (MAS). But unfortunately, in spite of its medicinal importance and drought
tolerance, the potential of this crop has not been realized by the government, nor at
the institutional levels. Very few researchers have explored its phenotypic and bio-
chemical diversity, while diversity at the DNA level is totally lacking and no molecu-
lar markers has been developed in this crop to date.
References
Allen, O. N., & Allen, E. K. (1981). The Leguminosae. A source book of characteristics, uses
and nodulation. Madison, WI: The University of Wisconsin Press.
Arora, R. K., & Chandel, K. P. S. (1972). Botanical source areas of wild herbage legumes in
India. Tropical Grasslands, 6, 213–221.
Asha, K. I., Latha, M., Abraham, Z., Jayan, P. K., Nair, M. C., & Mishra, S. K. (2006).
Genetic resources. In D. Kumar (Ed.), Horsegram in India (pp. 11–28). Jodhpur, India:
Scientific Publisher.
Bailey, F. M. (1900). The Queensland flora. Part II. Brisbane: Government Printer.
Bhag, M., & Joshi, V. (1991). Under-utilised plant resources. In R. S. Paroda & R. K. Arora
(Eds.), Plant Genetic Resources-conservation and management (p. 211). New Delhi,
India: Malhotra Publishing House.
Blumenthal, M. J., O’Rourke, P. K., Hilder, T. B., & Williams, R. J. (1989). Classification of
the Australian collection of the legume Macrotyloma. Australian Journal of Agricultural
Research, 40, 591–604.
Blumenthal, M. J., & Staples, I. B. (1993). Origin, evaluation and use of Macrotyloma as
forage – a review. Tropical Grassland, 27, 16–29.
Brink, M. (2006). Macrotyloma uniflorum (Lam.) Verdc. In M. Brink & G. Belay (Eds.),
PROTA1: Cereals and pulses. Wageningen, the Netherlands: PROTA.
Chahota, R.K. (2009). Induction of early flowering and other important traits in horse gram
(Macrotyloma uniflorum) using gamma irradiation. Final project report submitted to
Bhabha Atomic Research Centre, Trombay, India.
Chahota, R. K., Sharma, T. R., Dhiman, K. C., & Kishore, N. (2005). Characterization and
evaluation of horse gram (Macrotyloma uniflorum Roxb.) germplasm from Himachal
Pradesh. Indian Journal of Plant Genetic Resources, 18, 221–223.
Chaitanya, D. A. K., Santosh Kumar, M, Reddy, A. M., Mukherjee, N. S. V., Sumanth, M. H.,
& Ramesh, D. A. (2010). Anti urolithiatic activity of Macrotyloma uniflorum seed extract

Horsegram 303
on ethylene glycol induced urolithiasis in albino rats. Journalof Innovative Trends in
Pharmaceutical Sciences, 1(5), 216–226.
Dobhal, V. K., & Rana, J. C. (1994a). Multivariate analysis in horsegram. Legume Research,
17(3-4), 157–161.
Dobhal, V. K., & Rana, J. C. (1994b). Genetic analysis for yield and its components in horseg-
ram (Macrotyloma uniflorum). Legume Research, 17(3-4), 179–182.
Doyle, J. J., & Luckow, M. A. (2003). The rest of the iceberg. Legume diversity and evolution
in a phylogenetic context. Plant Physiology (Rockville), 131, 900–910.
Gaur, R. D., & Dangwal, L. R. (1997). A new species of macrotyloma from Garhwal
Himalaya, U.P., India. Bombay Natural Historical Society, 94, 381–383.
Gept, P., Beavis, W. D., Brummer, E. C., Shoemaker, R. C., Stalker, H. T., Weeden, N. F., et al.
(2005). Legumes as a model plant family. Genomics for food and feed report of the cross-
legumes advances through genomics conference. Plant Physiology, 137, 1228–1235.
Gopalan, C., Ramashastri, B. V., & Balasubramanyan, S. C. (1989). Nutritive value of Indian
foods. Hyderabad, India: National Institute of Nutrition, ICMR.
Gupta, V. P., Sharma, S. K., & Rathore, P. K. (1994). Induced mutagenic response of gamma
irradiation on horsegram (Macrotyloma uniflorum). Indian Journal of Agricultural
Sciences, 64, 160–164.
Jamadagani, B. M., & Birari, S. P. (1996). Modification in photoperiodic response of flower-
ing by gamma-rays induced mutation in horsegram. Journal of Maharashtra Agricultural
University, 21, 384–386.
Jansen, P. C. M. (1989). Macrotyloma uniflorum (Lam.) Verdc.: Plant resources of South-East
Asia, pulses. (pp. 53–54). Wageningen, the Netherlands: Pudoc.
Jayan, P. K., & Maya, C. N. (2001). Studies on germplasm collections of horsegram. Indian
Journal of Plant Genetic Resources, 14, 443–447.
Jayaraj, A. P., Tovey, F. I., Lewin, M. R., & Clark, G. C. (2000). Duodenal ulcer prevalence:
experimental evidence for possible role of dietary lipids. Journal of Gastroenterology and
Hepatology, 15, 610–616.
Joshi, S. S., Chikkadevaiah, & Shashidhas, H. E. (1994). Classification of horse gram germ-
plasm. Crop Research, 7(3), 375–391.
Kulkarni, G. B. (2010). Evaluation of genetic diversity of horse gram (Macrotyloma uniflo-
rum) germplasm through phenotypic trait analysis. Green Farming, 1(6), 563–565.
Kulkarni, G. B., & Mogle, U. P. (2011). Characterization and evaluation of horse gram
(Macrotyloma uniflorum (Lam.) Verdcourt) genotypes. Science Research Reporter, 1(3),
122–125.
Kumar, D. (2005). Status and direction of arid legumes research in India. Indian Journal of
Agriculture Sciences, 75, 375–391.
Lackey, J. A. (1981). Phaseolus. In R. M. Polhill & P. H. Raven (Eds.), Advances in legume
systematic Part I (pp. 301–327). Kew, London: Royal Botanic Garden.
Lad, B. D., Chavan, S. A., & Dumbre, A. D. (1999). Genetic variability and correlation studies
in horsegram. Journal of Maharashtra Agricultural University, 23, 268–271.
Latha, M. (2006). Germplasm characterization and evaluation of horticultural crops. Annual
report of NBPGR report-2006, New Delhi.
Mahajan, V., Shukla, S. K., Gupta, N. S., Majumdera, D., Tiwari, V., & Piiasad, S. V. S.
(2007). Identifying phenotypically stable genotypes and developing strategy far yield
improvement in horsegram (Macrotyloma uniflorum) for mid-altitudes of Northwestern
Himalayas. Indian Journal of Agricultural Sciences, 3, 19–22.
Mathew, K. M. (1983). The flora of Tamil Nadu Carnatic. Part one Polypetalae.
Tiruchirapalli, India: The Rapinat Herbarium, St. Joseph’s College.

Genetic and Genomic Resources of Grain Legume Improvement304
Mehra, K.L. & Magoon, M.L., (1974). Gene centres of tropical and sub-tropical pastures leg-
umes and their significance in plant introduction. Proceedings of the XII International
Grassland Congress, (pp. 251–256) Moscow.
Morris, J. B. (2008). Macrotyloma axillare and M. uniflorum: descriptor analysis, anthocyanin
indexes, and potential uses. Genetic Resources Crop Evolution, 55, 5–8.
Murthy, S. M., Devaraj, V. R., Anitha, P., & Tejavathi, D. H. (2012). Studies on the activi-
ties of antioxidant enzymes under induced drought stress in vivo and in vitro plants of
Macrotyloma uniflorum (Lam.) Verdc. Recent Research in Science and Technology, 4,
34–37.
Nagaraja, N., Nehru, S. D., & Manjunath, A. (1999). Plant types for high yield in horse-
gram as evidenced by path coefficients and selection indices. Karnataka Journal of
Agricultural Sciences, 12(1-4), 32–37.
Nair, N. C., & Henry, A. N. (1983). Flora of Tamil Nadu. India Series I: Analysis: (Vol. 1).
(pp. 1–184). Coimbatore, India: Botanical Survey of India Southern Circle.
National Academy of Sciences, (1978). Mothbean in tropical legumes : Resources for the
future. Washington, DC: National Academy of Sciences.
Negi, K. S., Yadav, S., Mandal, S., & Bhandari, D. C. (2002). Registration of wild horsegram
germplasm (INGR No. 02007; IC2I2722). Indian Journal of Plant Genetic Resources,
15(3), 300–301.
Patel, D. P., Dabas, B. S., Sapra, R. S., & Mandal, S. (1995). Evaluation of horsegram
(Macrotyloma uniflorum) (Lam.) germplasm. New Delhi, India: National Bureau of Plant
Genetic Resources Publication.
Patil, J. V., Deshmukh, R. B., & Singh, S. (1994). Selection of genotypes in horsegram based
on genetic diversity. Journal of Maharashtra Agricultural University, 19, 412–414.
Phan, H. T. T., Ellwood, S. R., Adhikari, K., Nelson, M., & Oliver, R. P. (2006). The first
genetic and comparative map of white Lupin (Lupinus albus L.) identification of QTLs
for anthracnose resistance and flowering time, and a locus for alkaloid content. DNA
Research, 14, 59–70.
Prakash, B. G., Channayya Hiremath, P., Devarnavdgi, S. B., & Salimath, P. M. (2010).
Assessment of genetic diversity among germplasm lines of horsegram (Macrotyloma uni-
florum) at Bijapur. Electronic Journal of Plant Breeding, 1, 414–419.
Pullaiah, T., & Chennaiah, E. (1997). Flora of Andhra Pradesh (India), Rananculace-
Alangiaceae: Vol. 1. Jodhpur, India: Scientific Publishers.
Purseglove, J. W. (1974). Dolichos uniflorus. Tropical crops: Dicotyledons. (pp. 263–264).
London and New York: Longman.
Ramakanth, R. S., Setharama, A., & Patil, N. M. (1979). Induced mutations in dolichos lablab.
Mutation Breeding Newsletter, 14, 1–2.
Ramesh, C. K., Rehman, A., Prabhakar, B. T., Vijay Avin, B. R., & Aditya, S. J. (2011).
Antioxidant potential in sprouts vs. seeds of Vigna radiata and Macrotyloma uniflorum.
Journal of Applied Pharmaceutical Sciences, 1, 99–103.
Rana, J.C., (2010). Evaluation of horsegram germplasm. Annual progress report of the
NBPGR, Shimla, India.
Savithriamma, D. L., Shambulingappa, K. G., & Rao, M. G. (1990). Evaluation of horsegram
germplasm. Current Research, 19(9), 150–153.
Sharma, R. K. (1995). Nature of variation and association among grain yield and yield compo-
nents in horsegram. Crop Improvement, 22(1), 73–76.
Smartt, J. (1985). Evolution of grain legumes. II. Old and new world pulses of lesser eco-
nomic importance. Experimental Agriculture, 21, 1–18.

Horsegram 305
Sodani, S. N., Paliwal, R. V., & Jain, L. K. (2004). Phenotypic stability for seed yield in rain-
fed horse gram (Macrotyloma uniflorum (Lam.) Verdc.): Proceedings of the national
symposium on arid legumes for sustainable agriculture and trade. Jodhpur, India: Central
Arid Zone Research Institute. November 5–7.
Sreenivasan, E. (2003). Hybridization studies in horse gram. In A. Henry, D. Kumar, &
N. B. Singh (Eds.), Advances in arid legumes research (pp. 115–121). Jodhpur, India:
Scientific Publishers.
Staples, I. B. (1966). A promising new legume. Queensland Agricultural Journal, 92,
388–392.
Staples, I.B., (1982). Intra and interspecific crosses in Macrotyloma axillare. Proceedings of
the Second Australian Agronomy Conference, p. 340, Wagga.
Subba Rao, A., & Sampath, S. R. (1979). Chemical composition and nutritive value of
horsegram (Dolichos biflorus). Mysore Journal of Agricultural Sciences, 13, 198–205.
Sudha, N., Mushtari Begum, J., Shambulingappa, K. G., & Babu, C. K. (1995). Nutrients
and some anti-nutrients in horsegram (Macrotyloma uniflorum (Lam.) Verdc.) Food and
Nutrition Bulletin, 16, 81–83.
Tripathi, A. K. (1999). Variability in horsegram. Annals of Agricultural Research, 20,
382–383.
Vavilov, N. I. (1951). Phytogeographic basis of plant breeding. Chronica Botanica, 13, 13–54.
Verdcourt, B. (1970). Studies in the Leguminosae–Papilionoideae for the ‘Flora of Tropical
East Africa’, III. Kew Bulletin, 24, 379–447.
Verdcourt, B. (1971). Phaseoleae. In J. C. Gillet, R. M. Polhill, & V. Verdcourt (Eds.), Flora
of east tropical Africa. Leguminosae–subfamily Papilionoideae (Vol. 2, pp. 581–594).
Crown Agents.
Verdcourt, B. (1980). The classification of Dolichos L. emend. Verdc., Lablab Adans.,
Phaseolus L., Vigna Savi and their allies. In R. J. Summerfield & A. H. Bunting (Eds.),
Advances in legume science (pp. 45–48). London, Kew Royal Botanic Gardens.
Wellington, M., Diop, N. N., Bhat, P. R., Fenton, R. D., Wanamaker, S., Porrorff, M., et al.
(2009). A consensus genetic map of cowpea (Vigna unguiculata (L.) Walp.) and synteny
based on EST-derived SNPs. PNAS, 27, 18159–18164.
Zeven, A. C., & de Wet, J. M. J. (1982). Dictionary of cultivated plants and their regions
of diversity. Wageningen, the Netherlands: Centre for Agricultural Publishing and
Documentation.
Zohary, D. (1970). Centers of diversity and centers of origin. In O. H. Frankel &
F. Bennett (Eds.), Genetic resources in plants (pp. 33–42). Oxford: Blackwell Scientific
Publications.