Wild relatives of Okra (Abelmoschus spp.) - An overview

Abstract

Wild relatives of okra gives a wide diversity in okra germplasm. The number of species recognized varies from 6 to 15. The genus has generally high chromosome numbers, and includes several allopolyploids. There is considerable variation in chromosome counts from single species, and it is not clear whether this is the result of the difficulty in counting of chromosomes, polymorphism in chromosome count, or the presence of cryptic species. Total 12 species are mentioned in the description. Out of 12 species Abelmoschus angulosus showed resistance to YVMV and to powdery mildew consistently whereas, Abelmoschus tuberculatus is resistant to the spiny bollworm and some of them are found useful for commercial scale.

Full text

Eco. Env. & Cons. 21 (1) : 2015; pp. (301-306)
Copyright@ EM International
ISSN 0971–765X
*Corresponding author’s email: gopnarkhede@gmail.com
Wild relatives of Okra (Abelmoschus spp.) – An
Overview
G.W. Narkhede1*, S.B. Deshmukh2 and S.M. Shinde3
Department of Genetics and Plant Breeding, College of Agriculture, Latur, M.S., India
Marathwada Krishi Vidyapeeth, Parbhani, India
(Received 26 August, 2014; accepted 30 September, 2014)
ABSTRACT
Wild relatives of okra gives a wide diversity in okra germplasm. The number of species recognized varies
from 6 to 15. The genus has generally high chromosome numbers, and includes several allopolyploids.
There is considerable variation in chromosome counts from single species, and it is not clear whether this is
the result of the difficulty in counting of chromosomes, polymorphism in chromosome count, or the presence
of cryptic species. Total 12 species are mentioned in the description. Out of 12 species Abelmoschus angulosus
showed resistance to YVMV and to powdery mildew consistently whereas, Abelmoschus tuberculatus is
resistant to the spiny bollworm and some of them are found useful for commercial scale.
Key words : Okra, Abelmoschus spp.
Introduction
Abelmoschus is genus of annual, biennial or perennial
malvaceous herbs placed in sub family Malvoidae
and tribe Hibisceae of the angiosperm family
Malvaceae, it is the segregate of Hibiscus. It is distin-
guished from Hibiscus by the possession of a
deciduos circumscissile spathaceous calyx. Species
of Abelmoschus are annual or perennial herbs or
shrubs, often ==hispid or tomentose, with mostly
simple hairs. The foliage is alternate, stipulate and
petiolate. The stipules are linear or filiform, and
caduos (soon falling off) or persistent (Sources con-
tradictory). The leaf blades are in palmately lobed,
with crenate or dentate margins. The flowers are
born solitary in leaf axils, or in terminal raceames.
They possess an epicalyx of from 4 to 16, depending
on species, mostly caduceus, bracteoles. The calyx is
spathaceous, that is split to the base on one side as
the flower opens, and lobed or toothed at the apex.
It is deciduous, falling with corolla and stamina col-
umn. The corolla is funnel – shaped, yellow or red,
rarely white or pink, often with darker eye, and usu-
ally large. The stamina column bears anthers
throughout its length, and has a five toothed apex.
The anthers are unilocular.
The ovary is 5-locular, the locules pluriovulate,
and style single with 5 sessile or subsessile flattened
capitate stigmas. The capsule is elongate, often 5-
angled, beaked or mucronate, pubescent or hispid,
and dehiscent (5-valved). The seeds are numerous,
and are subreniform, and sometimes pubescent or
squamose. The number of species recognized varies
from 6 to 15. The genus has generally high chromo-
some numbers, and includes several allopolyploids.
There is considerable variation in chromosome
counts from single species, and it is not clear
whether this is the result of the difficulty in counting
of chromosomes, polymorphism in chromosome
count, or the presence of cryptic species. The list of
wild species available all over the world given be-
low:

302 Eco. Env. & Cons. 21 (1) : 2015
Description
The short information regarding the 12 wild rela-
tives of okra given as below:
1 Abelmoschus angulosus:
Abelmoschus angulosus is a wild species recorded
from Sri Lanka, India (Gujrat, Kerala, Maharshtra
and Tamil Nadu), Pakistan, Cambodia, Laos, Viet-
nam, Java and Sumatra. Hooker’s Flora of British
India describes two varities – var. grandiflorus, with
scabrous (not hispid) petioles, yellow petals, and
subpyriform seeds, and var. purpurens, with rigid
spreading hairs on the petiole, purple petals and
globose seeds. Abelmoschus angulosus showed resis-
tance to YVMV and powdery mildew consistently
under all experimental conditions. [Samrajeewa et
al. 2004]. The chromosome number of Abelmoschus
angulosus : 2n = 56 {Ford, 1938}.
with 5 arms, each with a flat stigma. The chromo-
some number of Abelmoschus crinitus is 2n=138
(Kerala Agriculture University, Mannuthy).
Abelmoschus tuberculatus
Abelmoschus tuberculatus is a wild species from India,
morphologically similar to, and long confused with
Abelmoschus esculentus. However it has a different
karyotype (2n=58 versus 2n=130), and hybrids be-
tween it and Abelmoschus esculentus are sterile. Mor-
phologically it can be distinguished by the tubercu-
late fruits, and by being smaller in most parts, espe-
Fig. 1 Flower and Fruit of Abelmoschus angulosus var.
grandiflorus
Fig. 2. Flower and Fruit of Abelmoschus angulosus var.
purpurens
Abelmoschus crinitus
Abelmoschus crinitus is a wild species from southern
china (Guangxi, Guizhou, Hainan, Yunnan), India,
Nepal, Myanmar, Thailand and Vietnam. It is a pe-
rennial herb, growing to between 0.5 to 2.0 m in
height. The root is fusiform. The plant has an
indumentums composed of 5-6 mm long yellow
hairs and a minute gray puberulence. The corolla is
around 10 to 13 cm diameter, and is yellow with a
purple center. The stamina column is around 2 cm
long, with scattered anthers. The style is branched,
Fig. 3. Flower of Abelmoschus crinitus
Fig. 4. Fruit of Abelmoschus crinitus
Fig. 6. Fruit of Abelmoschus tuberculatus
Fig. 5. Flower of Abelmoschus tuberculatus

NARKHEDE ET AL 303
cially the fruits. Abelmoschus tuberculatus is resistant
to the spiny bollworm Earias insulana and to Okra
yellow vein mosaic virus, and therefore is of interest
for the potential transfer of those traits to
Abelmoschus esculentus.
4. Abelmoschus tetraphyllus
Abelmoschus tetraphyllus is sometimes classified as a
subspecies of Abelmoschus manihot. However, it has
a different cytotype {2n=138 versus 2n=68}. There
are two subspecies of Abelmoschus manihot var.
tetraphyllus:
Abelmoscus manihot var. tetraphyllus:
Chromosome number: {2n=130}
Originated from Southern Asia (Including India,
Myanmar and Thialand) and southwest pacific (In-
cluding Philippines, Moluccas and papua New
Guinea.
Abelmoschus manihot ssp tetraphyllus var.
pungens:
Chromosome number: {2n=138}
Indonesia, Philippines, Christmas Islands, Japan,
Cina, India, Nepal, the indo-chinese peninsula and
Myanmar. Reddish tinge on fruit and ridges are not
prominenet.
white in color turning pink.
Chromosome number: {2n=72}
Fig. 7. Flower and fruit A. manihot
Fig. 8. Flower and Fruit of A. manihot var. tetraphyllus
ssp tetraphyllus var pungens
Abelmoschus ficulneus
Abelmoscus ficulneus is found in the India subconti-
nent, Australia, Madagascar, and in the sahel zone
of Africa, including Niger and northen Nigeria, but
may be native, rather than naturalized, only in the
first. Abelmoschus ficulneus is prickly annual herb,
with palmately 3-5-lobed glabrous leaves. Flowers
Fig. 9. Flower of Abelmoschus ficulneus
Fig. 10. Fruit of Abelmoschus ficulneus
Fig. 12. Fruit of Abelmoschus
manihot
Fig. 11. Flower of
Abelmoschus manihot
Abelmoschus manihot
Abelmoschus manihot is native to India, Nepal and
southern China. It is an annual or perennial herb
growing 1 to 2 m. The corolla is yellow with a purple
centre, and about 12 cm in diameter. Abelmoschus
manihot sometimes grown as an ornamental. Fruit is
with 8 ridges on it.
Chromosome number: {2n=68}
Abelmoschus moschatus
Abelmoschus moschatus is native to India,
continenetal south east Asia and southern China. It
is an annual or perennial herb growing 1 to 2 m. The
corolla is yellow with purple centre, and about 7 to
Fig. 13. Abelmoschus moschatus

304 Eco. Env. & Cons. 21 (1) : 2015
12 cm in diameter. Abemoschus moschatus is grown
commercially for its musk scented seeds. It also
sometimes grown as an ornamental.
Abelmoschus caillei
Abelmoschus caillei is cultivated species from West
Africa, where it is originated as an allopolyploid
hybrid between Abelmoschus manihot and
Abelmoschus esculentus. The same allopolyploid has
been produced experimentally in Japan, where it
was given the names Nori-Asa and Abelmoschus
glutino-textile.
Abelmoschus muliensis
Abelmoschus muliensis is endemic to southwest
Sichuan, where it occurs on grassy slopes between
1200 m to 2100 m altitude. It is a velutinous herb
reaching 1 m in height, with a stem about 0.5 cm in
diameter, and most parts with a dense covering of
yellow hairs. The foliage is alternate, stipulate and
shortly petiolate. The stipules are narrow, and 1 to
1.5 cm long. The petiole is 1 to 4 cm long. The blades
of the lower leaves are 6-9 cm in diameter, and have
a rounded cordate base, and obtuse or acute apex
and a broadly dentate margin. Those of the upper
leaves are ovate-sagittate, 7-10 cm long and 5-7 cm
wide, with a broadly dentate margin and an obtuse
apex. The flowers have not been observed, however
from the fruiting stage it is known that the flowers
are born singly or in clusters in the leaf axils, and
that the epicalyx is composed 12 filiform lobes
which are 2-3 mm wide and 1.5-3 cm long.
Abelmoschus sagittifolius
Abelmoschus sagittifolius is often classified as subspe-
cies (tubrosus) of Abelmoschus moschatus. However it
has different karyotype (2n=36 versus 2n=72}, and
therefore it is separate species. {Flora of China}. It is
found in southern China (Guangdong, Guangxi,
Guizhou, Hainan, Yunnan), mainland south east
Asia, extending to eastern India, and also in the
Kimberely and Arnhem Land areas of northen Aus-
tralia. In China it is found in pine forests, on grassy
slopes, and in other habitats. It is also grown as an
ornamental. It is perennial herb, growing to 40 to
100 cm, or rarely 200 cm, tall. Most vegetative parts
are densely pubescent, and are sometimes also se-
tose or stellate-hairy. It has fleshy, radish-shaped,
rootstock, reaching to 5 cm in thickness. The flowers
are white, pale yellow or pink, and 4 or 5 cm in di-
ameter. They are borne solitary in the laef axils, on
slender but densely scabrous, 4 to 7 cm long, peti-
oles. The epicalyx composed of 6 to 12 filiform,
sparsely hirsute, spreading or reflexed, bracteoles.
These are around 15 mm long, and 1 to 1.7 mm
wide. The petals are 3 to 4 cm long with an oblong
shape.
Abelmoschus enbeepeegearensis
Morphologically allied to Abelmoschus crinitus and
Abelmoschus moschatus, but not freely crossable. Re-
stricted ecogeographic distribution to pockets in
Fig. 14. Abelmoschus caillei

NARKHEDE ET AL 305
Western Ghat (Kerala, Karnataka and Tamil nadu).
It is a rare species with distinct features. The hybrid
with Abelmoschus moschatus was sterile.
Abelmoschus spp (Guinean type)
The new West African okra species with 2n=194
chromosome is higher polyploid form which might
derived from Abelmoschus esculentus and
Abelmoschus manihot (Siemonsma, 1981). It is also
often classified under subspecies of Abelmoschus
manihot. The fruits of guinean type okra are ridge
less, cone shaped with slight red tinge on it.
Crossability Status
The proposed crossability status of wild relatives of
okra in between wild species and in between wild
Fig. 15. Plant of Abelmoschus enbeepeegearensis
Fig. 16. Flower and Fruit of Abelmoschus manihot var.
guinea
Table 1. Proposed Crossability Status
Cross A. esculentus × Chromosome No. Reference Indicated Reciprocal
cross cross
A. tuberculatus 130 x 58 Pal et al; (1952); Joshi et al; (1974) Positive Positive
124 x 58 Kuwada (1966) Positive Positive
A. manihot 72 x 60 Teshima (1933) Positive Negative
126 x 60 Chizaki; (1934) Positive -
130 x 66 Skovsted (1935) Positive Positive
124 x 68 Kuwada (1957) Positive Positive
A. ficulneus 130 x 72 Pal et al; (1952) Negative Negative
Gadwal et al; (1968) Negative -
Joshi et al; (1974)
A. moschatus 130 x 72 Skovsted; (1935) Positive Negative
130 x 72 Gadwal et al; (1968) Negative
Joshi et al; (1974)
A. pungens 130 x 138 Gadwal (In : Joshi & Hardas; 1976) Positive
A. tetraphyllus 130 x 138 Gadwal (In : Joshi & Hardas; 1976) Positive
130 x 138 Suresh Babu (1987) Positive
72 x 130 Ugale et al; (1976) Positive
Guinean Type 130 x 194 Singh & Bhatnagar (1975) Positive
and spp esculentus mentioned in Table 1.
Hybrids
A several species of Abelmoschus are significant
crops there has been appreciable research on inter-
specific hybridization. Siemonsaa (1981) reports that
attempts to produce hybrids among Abelmoschus
manihot, moschatus and ficulneus were unsuccessful.
-Abelmoschus caillei x Abelmoschus esculentus:
can be crossed.
-Abelmoschus caillei x Abelmoschus manihot:

306 Eco. Env. & Cons. 21 (1) : 2015
This can be crossed. The cross is only successful
when Abelmoschus caillei is the seed parent.
-Abelmoschus esculentus x Abelmoschus
angulosus: This can be crossed.
-Abelmoschus esculentus x Abelmoschus
tuberculatus: Abelmoschus esculentus and tuberculatus
can be crossed without the need for any intervention
other than emasculation and hand pollination. The
hybrids show hybrid vigour, but are sterile. A fertile
allopolyploid, which retains hybrid vigour, has been
created by colchicines treatment.
-Abelmoschus esculentus x Abelmoschus
manihot: Abelmoschus esculentus and manihot can be
crossed. The hybrids shows hybrid vigour, but are
partial sterile. A fertile allopolyploid has been pro-
duced which can be inferred to be conspecific with
Abelmoschus caillei.
-Abelmoschus esculentus x Abelmoschus
tetraphyllus: Abelmoschus esculentus and tetraphyllus
can be crossed. An allopolyploid can be produced.
-Abelmoshus esculentus x Abelmoschus
moschatus: This can be crossed, with difficulty.
[Hamon & Koechlin, Euphytica 53:49-55(1991)]
-Abelmoschus sp. aff.esculentus x Abelmoschus
tetraphyllus: The 72 chromosome race of Abelmoscus
esculentus can be crossed with Abelmoschus
tetraphyllus.
-Abelmoschus ficulneus x Abelmoschus
tuberculatus: Abelmoschus ficulneus and tuberculatus
can be crossed. The resulting plants are sterile. An
experimental allopolyploid has been produced, and
is also sterile.
-Abelmoschus manihot x Abelmoschus
tuberculatus: Abelmoschus manihot and tuberculatus
can be crossed. The resulting plants are sterile.
References
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and its relation to Abelmoschus esculentus
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Wu, Z.Y., Raven, P.H. and Hong, D.Y. 2007. Flora of China
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Kubitzki and Bayer, Malvaceae, in Kubitzki and Bayer,
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