African Journal of Plant Science - Academic Journals

African Journal of
Plant Science
Volume 6 Number 10 July 2012
ISSN 1996-0824

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Prof. Diaga Diouf
Laboratoire de Biotechnologies végétales,
Département de Biologie Végétale,
Faculté des Sciences et Techniques,
Université Cheikh Anta Diop, BP 5005,
Dakar, Sénégal.
Prof. Amarendra Narayan Misra
Center for Life Sciences, School of Natural Sciences,
Central University of Jharkhand,
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Ranchi, Jharkhand State,
India.
Associate Editors
Dr. Ömür Baysal
Mugla University
ASMK Vocational School
Technical Programs PB. 48300
Fethiye -Mugla
Turkey.
Dr. R. Siva
School of Bio Sciences and Technology
VIT University
Vellore 632 014.
Dr. Biswa Ranjan Acharya
Pennsylvania State University
Department of Biology
208 Mueller Lab
University Park, PA 16802.
USA
Dr. Ali Masoudi-Nejad
Assistant Professor of Bioinformatics
Institute of Biochemistry and Biophysics (IBB)
University of Tehran,Tehran,
Iran.
Prof. H. Özkan Sivritepe
Department of Horticulture Faculty of
Agriculture Uludag University Görükle
Campus Bursa 16059
Turkey.
Prof. Ahmad Kamel Hegazy
Department of Botany, Faculty of Science,
Cairo University, Giza 12613,
Egypt.
Dr. Annamalai Muthusamy
Department of Biotechnology
Manipal Life Science Centre,
Manipal University,
Manipal – 576 104
Karnataka,
India.
Dr. Chandra Prakash Kala
Indian Institute of Forest Management
Nehru Nagar, P.B.No. 357
Bhopal, Madhya Pradesh
India – 462 003.

Editorial Board
Prof. Weimin Zhang
Guangdong Institute of Microbiology
100 Central Xian lie Road, Guangzhou, Guangdong 510070,
China
Specialization: Microbiology, biochemistry and molecular
biology, natural
product chemistry
China
Dr. Xu Suxia
Fujian Institute of Subtropical Botany
780-800, Jiahe Road, Xiamen, China361006
Specialization: Plant physiology and biochemistry
China
Dr. Adaku Vivien Iwueke
Federal University of Technology, Owerri
Department of Biochemistry, Federal University of
Technology, Owerri
Specialization: Pharmacological/Nutritional Biochemistry
Nigeria
Ass. Prof. Turgay CELIK
Gulhane Military Medical Academy,
School of Medicine,
Department of Cardiology
Specialization: Interventional cardiology, clinical
cardiology, intensive care
Turkey
Dr.Topik Hidayat
Department of Biology Education
Indonesia University of Education (UPI)
Jalan Dr. Setiabudhi 229 Bandung 40154 Indonesia
Specialization: Botany
Indonesia
Dr.Tariq Mahmood
Quaid-i-Azam University,
Department of Plant Sciences, Quaid-i-Azam University,
Islamabad, Pakistan
Specialization: Biochemistry, Molecular Biology,
Bioinformatics, Biotechnology
Pakistan
Dr.Neveen B. Talaat
Department of Plant Physiology, Faculty of Agriculture,
Cairo University, Egypt
Specialization: Plant Physiology
Plant Molecular Biology: Plant Transformation
Plant nutrition
Egypt
Dr. Sudhamoy Mandal
Central Horticultural Experiment Station (ICAR)
Aiginia, Bhubaneswar, PIN-751019
Specialization: Induced resistance (SAR, ISR) in plants,
Oxidative burst, Biocontrol of plant diseases, Defense
signaling in plants
India
Asso. Prof. Chankova Stephka Georgieva
Central Laboratory of General Ecology, Bulg Acad Sci
1113 Sofia, 2 Gagarin str, Bulgaria
Specialization: Genetics - environmental mutagenesis;
molecular eco-toxicology, stress response
Bulgaria
Shijie Han
Center of Forestry, Institute of Applied Ecology, Chinese
Academy of Sciences,
72 Wenhua Road, Shenyang City, Liaoning Province 110016,
PR China
Specialization: Global change biology, Plant ecology, Soil
ecology
PR China
Szu-Chuan Shen
Department of Medical Nutrition,
I-Shou University
Yanchao Township,
Kaohsiung County 824,Taiwan
Specialization: Food Nutrition
Taiwan
Seddik Khennouf
Dept of BIOLOGY, Faculty of Science
University Ferhat Abbas, SETIF, 19000, ALGERIA
Specialization: Pharmacology of phenolic compounds,
medicinal plants
ALGERIA
Saranyu Khammuang
Mahasarakham University
Department of Chemistry, Faculty of Science
Specialization: Plant biotechnology, Protein and peptide
chemistry, Enzymology
Thailand
Samir Ranjan Sikdar
Bose Institute
P-1/12, C.I.T. Scheme VII M, Kolkata 700 054, India
Specialization: Genetics, Plant Breeding, Tissue culture,
protoplast culture and somatic hybridization with special
reference to Brassica and edible mushrooms.
India
Dr. M. Abdul Salam
Department of Agronomy, College of Agriculture
Kerala Agricultural University, Vellayani 695 522,
Trivandrum, Kerala
Specialization: Agronomy of tropical crops, Plant nutrition,
Cashew nut Production and Processing, Organic production
of tropical vegetables and fruits, Irrigation water

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International Journal of Medicine and Medical Sciences
African Journal of Plant Science
Table of Contents: Volume 6 Number 10 July, 2012
nces
Review
ARTICLES
Allelopathy in aquatic macrophytes: Effects on growth and physiology of
phytoplanktons 270
Yalew Addisie and Andrea Calderon Medellin
Research Articles
Propagation and growth from cultured single node explants of rosa (Rosa
miniature) 277
Farah Farahani and Soodeh Shaker
Effect of time of harvest on physiological maturity and kenaf
(Hibiscus canabinus) seed quality 282
Olasoji J.O., A.O. Aluko, O.N. Adeniyan, S.O. Olanipekun ,
A.A. Olosunde and Okoh J.O.

African Journal of Plant Science Vol. 6(10), pp. 270-276, July 2012
Available online at http://www.academicjournals.org/AJPS
DOI: 10.5897/AJPS12.008
ISSN 1996-0824 ©2012 Academic Journals
Review
Allelopathy in aquatic macrophytes: Effects on growth
and physiology of phytoplanktons
Yalew Addisie 1 * and Andrea Calderon Medellin 2
1 Department of Biology, College of Natural and Computational Sciences, Mekelle University, P. O. Box 231, Mekelle,
Ethiopia.
2 Universidad Militar Nueva Granada, Bogota, Bolivar, Colombia.
Accepted 17 May, 2012
The present review discussed allelophatic effects of aquatic macrophytes on phytoplankton with
emphasis on growth and physiology; and also indicates implication for control of invasive aquatic
macrophyte and phytoplankton species. In view of the fact, inhibition of phytoplankton by
allelochemicals released by macrophytes is supposed to be one of the mechanisms that contribute to
stabilisation of clear-water states in shallow lakes. This is achieved through the effects of
allelochemicals on growth, photosynthesis and enzymatic activities of the phytoplanktons. The
reciprocal/counter act mechanisms of target phytoplankton to allelochemicals are still ill defined.
Reciprocal allelopathic responses between macrophytes and other phytoplankton species would have
implications for management of eutrophic waters. Therefore, understanding the molecular mechanisms
and the genetic bases of such effect is important. In addition to these, the molecular and genetic bases
of allelopathy of invasive species of aquatic macrophytes are not well studied and utilizing the outputs
to develop potential control is done through engineering.
Key words: Allelopathy, enzymatic activity, macrophytes, phytoplanktons.
INTRODUCTION
The phenomenon of chemical interactions among plants,
fungi, bacteria, and animals has gained great attention by
researchers from all over the world. Ever since, biological
interactions have survival values to keep ecosystem
integrations. Such chemically mediated interaction
between plants or microorganisms is termed allelopathy
(Rice, 1984). This mainly occurs in organisms releasing
or secreting their own chemical substances named
allelochemicals into a surrounding medium and eliciting
either positive or deleterious response in target organism
(Rice, 1984). Aquatic macrophytes (AM) including
macroalgae from the long shore, floating as well as deep-
water zone in the freshwater environment have
*Corresponding author. E-mail: albertu2009@gmail.com.
widespread allelopathy on phytoplankton (Gopal and
Goel, 1993; Inderjit and Dakshini, 1994). Different
investigations have shown the existence of diverse
allelochemicals identified from AM and well documented
their inhibition and stimulating effect (Gross, 2003; Hilt et
al., 2006; Mulderij, 2006; Gross et al., 2007;
Abdulrahman, 2010). Allelochemicals can interfere with
many processes of target organisms (Einhellig, 2001).
Allelopathically active compounds from AMs are often
directed at numerous physiological processes such as
photosynthesis and enzyme activities and growth and
development of phytoplanktons. Therefore, the present
review attempts to discuss allelophatic effects of some
AMs on phytoplankton with emphasis on growth and
physiology. Moreover, it tries to indicate implications for
the control/management of invasive AM and
phytoplankton species.

Figure 1. Schematic representation of allelopathic interactions between aquatic macrophytes and
phytoplanktons.
Allelopathy: An ecological overview
Eutrophication and algal blooms are the most serious
environmental problems. Search for allelopathic effects of
AMs on phytoplanktons’ growth and development
has receiving world-wide attention in order to develop
biological tools which are environmentally friendly to
mitigate such challenges. This is due to the reason that
inhibition of phytoplankton by allelochemicals released by
submerged macrophytes is supposed to be one of the
mechanisms that contribute to the stabilisation of clearwater
states in shallow lakes. Since allelopathy of AMs is
of significance on composition of communities in fresh
water ecosystems and ecological rehabilitation of
eutrophic lakes (Korner and Nicklisch, 2002). This is
achieved through allelopathic growth inhibition of
phytoplankton by AMs which might confer an advantage
to macrophytes in the competition for light, carbon, and
nutrients (Gross, 2003) and change the succession of
phytoplankton. However, understanding the factors which
regulate or control the extent of allelopathic effects such
as light and nutrient limitation of both the donor and the
target organisms is vital. In view of the fact, production of
Addisie and Medellín 271
secondary metabolites for plant defense related to light
and nutrient availability (Cronin and Lodge, 2003),
temperature (Albert et al., 2009) and biotic factors such
as herbivory (Lemoine et al., 2009). Thus, allelopathy and
other processes for plant defense cannot always be
separated. Only few studies relate allelochemical
production of AMs to abiotic and biotic influences.
Although allelopathy also includes positive (stimulating)
interactions, majority of the studies describe the inhibitory
activity of allelopathically active compounds. Such
inhibitory and simulative interactions are explained with
tremendous growth, physiological and biochemical
mechanisms which are discussed subsequently. Six
prerequisites have to be met to show unequivocally the
occurrence of allelopathy: (1) a pattern of inhibition of
target plant(s) or alga(e), (2) allelopathical compound(s)
produced by donor plants, (3) release of these
compounds by the producing plant, (4) transport and/or
accumulation in the environment, (5) uptake by the target
organism(s), and (6) that the inhibition cannot be
explained solely by other physical or biotic factors,
especially competition; and it is summarized
schematically in Figure 1.

272 Afr. J. Plant Sci.
Cell density (×10 3 cells ml -1 )
Cell density (×10 6 cells ml -1 )
Figure 2. Growth-inhibition and cell lysis effects of the extract of U. lactuca dry powder on harmful algal
bloom species of (A) A. anophagefferens, (B) C. marina. Data points are means ± SD (n = 3) (Source:
Tang and Gobler, 2011).
Allelopathy and its effect on growth of phytoplankton
and macrophytes
Virtually various in situ and ex-situ experiments
conducted to confirm allelopathy in AMs have shown its
suppressing performance on phytoplankton growth. It is
quite possible that allelochemicals may produce more
than one effect on the cellular processes responsible to
reduce phytoplankton growth. However, the details of the
biochemical mechanism through which a particular
allelochemical exerts a toxic effect on growth are not well
known. The existing evidences suggest that the
mechanism of growth inhibition of allelochemicals from
macroalgae and macrophytes is dependent on the nature
of the chemical elicited and genotype and diverse in type.
For instance, the mechanism of growth inhibition of the
green macro alga Ulva lactuca on harmful algal bloom
species via allelopathy is achieved through cell lysing and
decreasing cell density (Jin et al., 2005) (Figure 2).
However, some macrophytes release allelochemicals
which induce high rate of photosynthesis that might draw
down CO2 and in turn increases pH level. Subsequently,
this would have influence on processes involved in
growth and developments of phytoplankton and other
aquatic macrophytes (Lundholm et al., 2005). In this
case, the presumption is that, high pH invoked
allelopathic effects through interfering biochemical
reactions and nutrient scavenging. Moreover, production
of allelochemicals such as polyunsaturated fatty acids in
Ulva (Alamsjah et al., 2005) and dithiolane and trithiane
compounds identified from Chara sp. cause allelopathic
effects on growth of epiphytic diatoms and other
phytoplanktons (Wium-Anderson et al., 1982). Such
influence of allelochemicals on growth of phytoplanktons
would have negative consequences on the biomass
production (Qiming et al., 2006).
Effects on physiological activities
Aquatic allelochemicals often target multiple physiological
processes. Allelochemicals have significant effect on cell
division, cell differentiation, respiration, photosynthesis,
enzyme function, signal transduction as well as gene
expression (Inderjit, 2003; Belz and Hurle, 2004) in both
autotrophs of aquatic and terrestrial ecosystems. The

Figure 3. Inhibition of photosynthetic O2 evolution of Anabaena sp. PCC 7120 by addition of
different fractions of the solid phase extcraction(SPE) of M. spicatum extract (1, water, 2,
25% (v/v) MeOH; 3, 50% (v/v) MeOH; 75 (v/v) MeOH; and 100% (v/v) MeOH). The amount of
exctract used in the experiment was equivalent to 19 µg TAE ml -1 . Error bars indicate SE; n =
3 to 7 measurements per treatment. Significance differences between treatment and control
are shown by asterisk (P

274 Afr. J. Plant Sci.
Figure 4. The z-scheme of electron transport chain (red arrows) of the thylakoid membrane the (grey bar)
in the chloroplasts with photosystem I and II (green ovals, PSI and PSII) and
the target site of tellimagrandium II (blue arrow) between the quinine electron acceptors QA and QB. Abbrevi
ations: Pheo: pheophytin; PQ: plastochinon; PQH2: reduced plastochinon; Fd: ferrodoxin and PC: phycocya
nin. (Source: http://www.fsbio hannover.de/oftheweek/120.htm).
the secondary quinine electron acceptors, QA and QB in
the PSII (Figure 4). These allelochemicals act on a
different site of action. The decline in rate of
photosynthesis might be ascribed to decrease in amount
of chlorophyll contents due to allelochemicals
(Abdulrahman, 2010). For example, experiment
conducted on the effect of allelochemicals from
Myriophyllum aquaticum on photosynthetic pigments of
Microcystis aeruginosa showed that relative content of
chlorophyll a, phycocyanin and allophycocyanin
decreased to 52.7, 15.3 and 7.6%, respectively (Wu et
al., 2008) and the decline rate of assimilation is to that
extent. The authors also reported that phycobiliprotein
decreased more than Chlorophyll a.
Inhibition of enzymes
Many aquatic organisms produce extracellular enzymes
that enable them to use complex substrates or are
involved in the colonization of surfaces (Wetzel, 1991).
However, several enzymatic processes are inhibited by
allelochemicals from AMs. Interference with these
enzymes can alter competitive interactions among
organisms, change settling of organisms, and interfere
with biofilm formation and/or epiphyte growth. For
example, polyphenolic extracts from freshwater
submersed angiosperms, M. spicatum and Stratiote
aloides inhibit the enzyme alkaline phosphatase (Gross
et al., 1996; Abdulrahman, 2010). But the inhibitory effect
is genotype dependent (Figure 5). These findings
suggested that inhibition of extracellular alkaline
phosphatase could be one mode of action of
allelopathically active compounds. This might have
growth inhibition effect as alkaline phosphatase activities
are concomitant with growth of phytoplanktons (Hilt,
2006). Enzyme inhibition can harm the whole organisms
such as decreased dehydrogenase activity (for example,
M. aeruginosa) and increased the level of reactive
oxygen species (ROS) (Hong et al., 2009). The favoured
production of ROS is as consequence of much lipid
peroxidation by allelochemicals in algal cells directs to
reduce algal cell proliferation (Wu et al., 2007). More to
the point, a study conducted to test the inhibitory effect of
the allelochemical, gramine, on cyanobacterium (Hong et
al., 2010) showed that gramine caused significant

(U mg -1 protein)
APA activities (U mg -1 protein)
(mg ml -1 Concentration of S. aloides extract (mg ml ) -1 )
Figure 5. Effect of aqueous acetone extract of Stratiotes aloides on alkaline phosphatase activity
of Scendesmus obliquus (After: Abdulrahman, 2010).
increase of ROS. These also lowered activities of
antioxidant enzymes, such as superoxide dismutase and
peroxidase, can lead to increased oxidative damage,
metal ion leakage and changes in plasma integrity (Li and
Hu, 2005). According to these authors also ethyl 2methylacetoacetate
from Phragmites communis showed
changes in plasma membrane integrity and leakage of
ions in the protoplast (Li and Hu, 2005). Furthermore,
other modes of action of allelochemicals among
phytoplankton are for example cellular paralysis reported
of Anabaena flos-aquae affecting motile green algae
(Kearns and Hunter, 2001) as well as the inhibition of
nucleic acid synthesis (Einhellig and Reigosa, 2002) or
RNA polymerase by alkaloids (Doan et al., 2000).
Future research areas and implication to invasive
species control
The research of the allelopathy of AMs on phytoplanktons
is developing very fast. With many findings on new
allelochemicals, it will become the most promising
method to control algal bloom and invasive species.
However, there still exist some important problems to be
solved before it can be used in practice. The existing
studies mainly focus on floating and submerged
macrophytes, less studies on the emergent macrophytes.
Addisie and Medellín 275
Investigation on allelopathic activities of the AMs with
abundant biomass is still extremely limited. Some
allelochemicals have been identified from macrophytes,
but the highly-effective allelochemicals are still very few.
So, it still will be an important issue to search for highlyeffective
allelochemicals from aquatic macrophytes. The
studies on modes of action of allelochemicals will help to
modify the structure of allelochemicals artificially and
adjust their activities to be much more efficient. Most of
the existing researches are carried out in lab scale. The
lab-scale system was too simple to reflect the actual
circumstances of field. Since, under lab-conditions, it
remains difficult to prove the influence of combination of
abiotic and biotic interactions’ on the allelochemicals in
the same way as the in situ conditions. Therefore, future
researches in analyzing the presence of allelopathic
substances should focus on studies with intact
macrophytes and experimental setups in which it is
possible to make a clear distinction between allelopathy
and other growth limiting factors.
Currently, majority of allelopathic studies focus on
negative effects exerted by one species on another,
however, understanding the stimulation effect of some
allelochemicals for the normal growth and development
of some groups would have great contribution in
developing mitigation mechanisms for harmful blooming
algae and invasive macrophytes. Also, elucidating the

276 Afr. J. Plant Sci.
reciprocal or counter act mechanisms of target
phytoplankton to allelochemicals are still ill-defined and it
could be possible future research areas. Reciprocal
allelopathic responses between macrophytes and other
phytoplankton species would have implications for the
management of eutrophic waters. Majority of reports
have indicated that allelochemicals negatively influence
the growth and physiological processes such as enzyme
activities and photosynthesis. Therefore, understanding
the molecular mechanisms and the genetic bases of such
effect is important. In addition to these, the molecular and
genetics bases of allelopathy of invasive species of AMs
are not well studied and utilizing the outputs to develop
potential control is done through engineering.
ACKNOWLEDGEMENT
We would like to express our sincere appreciation and
gratitude to Mr. Addisu Tegegne Jimma University,
Ethiopia for his encouragement and comment on the
work.
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Cronin G, Lodge DM (2003). Effects of light and nutrient availability on
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Doan NT, Rickards RW, Rothschild JM, Smith GD (2000). Allelopathic
actions of the alkaloid12-epi-hapalindole E isonitrile and calothrixin A
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African Journal of Plant Science Vol. 6(10), pp. 277-281, July 2012
Available online at http://www.academicjournals.org/AJPS
DOI: 10.5897/AJPS12.037
ISSN 1996-0824 ©2012 Academic Journals
Full Length Research Paper
Propagation and growth from cultured single node
explants of rosa (Rosa miniature)
Farah Farahani 1 * and Soodeh Shaker 2
1 Department of Microbiology, Qom Branch, Islamic Azad University, Qom, Iran.
2 Plant Biotechnology Department, Karaj Center, Payame Noor university, Karaj, Iran.
Accepted 21 May, 2012
Roses are one of the world's most important ornamentals for a long time and are most often used for
ornamental, medicinal and aromatic purposes. A method for the proliferation and growth of rose (Rosa
miniature) was developed. First to seventh nodal explants from young healthy shoots were excised and
cultured on basal medium of Murashige and Skoog (1962, MS) containing several concentrations of
Benzyl amino purine (BAP) and indol butyric acid (IBA). Multiple shoot formation of up to 4 shoots from
a single node was obtained on MS medium supplemented with 2 mgl -1 BAP and 0.1 mgl -1 IBA. The mean
length of shoots were 38 mm. The mean number of leaves 13 and color of leaves red-green were
observed. The regenerated shoot readily rooted on as the same MS medium with growth regulators,
mean length of root were 33 mm. In vitro flowering will observe on rose plants cultured.
Key word: Proliferation, Rosa miniature, ornamental, rooting.
INTRODUCTION
Roses have been one of the world’s most popular
ornamental plants for a long time. They belong to the
Rosaceae and are grown worldwide as cut flowers and
potted plants and in home gardens. The flowers vary
greatly in size, shape and color. There are more than
20000 commercial cultivars of rose "the most important
commercial crops" which collectively are based on only
80 of the approximately 200 wild species in Rosa
(Razavizadeh and Ehsanpour, 2008).
Roses can be propagated by seeds, cutting, layering
and grafting. Seed propagation often results in variation
while other methods of rose propagation are low and time
consuming. So, there is need to introduce efficient
methods for faster propagation of roses (Shabbir et al.,
2009). Tissue culture system in roses has been
established (Hsia and Korban, 1996; Kintzios et al., 1999;
Ibrahim and Debergh, 2001; Kim et al., 2003; Rout et al.,
2006; Hameed et al., 2006; Drefahl et al., 2007; Previati
*Corresponding author. E-mail: farahfarahni2000@yahoo.com.
Tel: +989122778171. Fax: +982166551802.
Abbreviation: BAP, Benzyl amino purine; IBA, indol butyric
acid.
et al., 2008). Recently, in vitro flower induction in roses
was demonstrated (Wang et al., 2002; Vu et al., 2006).
The flowering process is one of the critical events in the
life of plant. This process involves the switch from
vegetative stage to reproductive stage of growth and is
believe to be regulated by both internal and external
factors (Kanchanapoom et al., 2010). To establish an in
vitro flowering research system, it is necessary to
develop a reliable and rapid shoot organogenesis
protocol. In this context, we describe an efficient tissue
culture technique to yield large number of shoots from
single node explants of rose. This study is part of a larger
program designed to investigate in vitro flowering of Rosa
species.
MATERIALS AND METHODS
Plant materials
The single node explants containing lateral buds of actively fieldgrown
‘Miniature’ rose were used for multiplication experiments.
They were cut in 5-6 cm length segments and surface-disinfested
using 70% ethanol for 20 s and then immersed in laundry bleach
(5.25% Hypochorite Sodium) solution of commercial containing 2
drops of Tween-20 emulsifier to aid wetting for 20 min (Nak-Udom
et al., 2009). The sterilized explants were washed 2-3 times with

278 Afr. J. Plant Sci.
Number of Leaves
Lenght of Root (mm)
Lenght of Shoot (mm)
Number of Shoot
50
40
30
20
10
0
6
5
4
3
2
1
0
40
30
20
10
0
25
20
15
10
5
0
a
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Treatments
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
b
Treatments
c
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Treatments
d
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Treatments
Figure 1. In vitro culture of Rosa miniature (a) Mean length of
shoot; (b) mean of number of shoot; (c) length of root; (d) number of
leaves in different treatments.
sterile distilled water to remove disinfecting solution. They were
trimmed down to 1 cm long prior to transferring to shoot
multiplication medium.
Proliferation and growth
The basal nutrient medium containing MS (Murashige and Skoog,
1962) salts and vitamins was used with IBA and BAP. In the
experiments, IBA at the concentrations of 0, 0.05 and 0.1 mgl -1 was
combined with BAP at the concentrations of 0, 0.5, 1, 1.5 and 2 mgl -
1 . Explants were subcultured to fresh medium every 6 weeks.
In vitro conditions
All media were supplemented with 3% sucrose and 7 gl -1 agar. The
pH of all media was adjusted to 5.7 with 1 N NaOH or 1 N HCl prior
to autoclaving at 1.05 kgcm -2 , 121°C for 20 min. Cultures were
maintained at 25±1°C air temperatures in a culture room with a 16 h
photoperiod under an illumination of 20 mmolm- 2 s- 1 photosynthetic
photon flux density provided by cool-white fluorescent light. Plant
materials were stored in glass-capped culture jars (125 ml capacity)
each containing 20 ml of medium.
Statistical analysis
Number of shoots and roots were evaluated after each culture
period. A culture cycle was 6 weeks. Three explants were implanted
per culture and 20 cultures were raised for each treatment unless
otherwise stated. All of experiments were repeated for 3 times for
each treatment used and morphological data were analyzed by
analysis of variance test (ANOVA) followed by least significant
difference test (LSD).
RESULTS AND DISCUSSION
After approximately one week, most explants turned
green and the node began to expand. Visible elongation
of the node on shoot induction medium was observed
within 10 days. New budding gradually occurred and
reached climax at 4 to 6 weeks (Figure 2a, b and c).
After 6 weeks of initial culture, nodal explants
containing lateral buds cultured on MS medium in the
experiments developed multiple shoots at a high
frequency of 100% with 4 ± 0.66 shoots on 2 mgl -1 BAP
and 0.1 mgl -1 IBA (Figure 1a, b and c). There was no
significant difference in shoot number per single node
explants; however, regeneration frequency differed
(Table 1). In the present study, multiplication occurred in
all BAP containing media this may be attributed to the
presence of IBA. Results revealed that highest level of
BAP (2 mgl -1 ) gave the highest number of 3.46 ± 0.6
shoots (P

Farahani and Shaker 279
Figure 2. In vitro culture of Rosa miniature. (a) Shoot initiation from single node explants (b) shoot multiplication
(c) shoot elongation (d) rooting, with long roots (e) with large number of small roots.

280 Afr. J. Plant Sci.
Table 1. Effect of different concentrations of BAP and IBA (Treatments) on adventitious shoot formation and rooting from single node
culture of Rosa miniature (This is grouping according to Duncan's test).
Treatment BAP (mg/l) IBA (mg/l)
Length of
shoot (mm)
Number of
branch
Length of
root (mm)
Number of
leaves
Colour of
leaves
T1 0 0 0 a 0 a 0 a 0 a _
T2 0.5 0.5 1 a 3.44 bc 0 a 5.22 ab Green
T3 1 1 22.22 b 3.66 c 0 a 8.55 b Green
T4 1.5 1.5 12.33 b 3.66 c 0 a 10.55 bc Green
T5 2 2 13.33 b 5.66 d 0 a 21.88 d Green
T6 0 0 15 b 2.77 bc 0 a 11.11 bc Green
T7 0.5 0.5 12.77 b 1.66 ab 0 a 6.66 ab Green
T8 1 1 20.55 b 2.33 bc 0 a 6.11 ab Green
T9 1.5 1.5 21.66 b 2.66 bc 0 a 10.22 bc Green
T10 2 2 22.22 b 2.22 b 0 a 10 bc Green
T11 0 0 20 b 2.33 bc 0 a 7.66 ab Green
T12 0.5 0.5 21.66 b 2.77 bc 0 a 12.33 bc Green
T13 1 1 20.55 b 1.77 bc 0 a 17.22 cd Green
T14 1.5 1.5 34.33 c 3.26 bc 21.66 b 18 cd Red-Green
T15 2 2 38.46 c 3.46 bc 33.07 c 13.38 bc Red-Green
The mean differences are significant at the 0.05 level.
stage. Previous research shows on other rose species
regarding development of multiple shoot on regeneration
media containing BA and IBA (Khosh-Khui and
Jabbarzadeh, 2007; Kumar et al., 2001) or BA and NAA
(Drefahl et al., 2007; Vu et al., 2006; Wang et al., 2002)
with intervening callus phase. These in vitro regenerated
shoots were further multiplied on this medium by
successive subculture, after every six weeks.
Telgen et al. (1992) studied effects of different growth
regulators and inhibitors on sprouting and outgrowth of
isolated buds of different rose cultivars and reported bud
growth stimulation by BAP. At all concentrations of BAP
and IBA tested, multiple shoots developed without the
intervening callus stage. BAP or NAA have been used for
most experiments on shoot multiplication of a number of
rose species (Wang et al., 2002; Vu et al., 2006; Drefahl
et al., 2007). These multiple shoots with green expanded
leaves and single main stem continued to proliferate after
several subcultures with an average of 4 shoots per
cycle. The mean of number leaves is significant in T3 and
T5 (Table 1). Clonal propagation of shoots was achieved
by repeating subculture at 6 weeks intervals. Each nodal
explant provided 16 shoots in 12 weeks, for a total
production of 55 plantlets per six months.
During investigation, it was also observed that 2 mgl -1
BAP was best for shoot whereas lower (0.5 to 1.5 mgl -1 )
and higher concentrations (> 2 mgl -1 ) inhibited it. This is
in accordance with the study conducted by Kim et al.
(2003) in which they reported that lower concentration of
BAP (0.5 to 1.5 mgl -1 ) stimulated the bud growth in six
rose cultivars (Rosa hybrida L. cv. "Sequoia Ruby", "Play
Boy") but higher concentration of BAP (2.5-4 mgl -1 )
inhibited shoot proliferation (Hameed et al., 2006). Roots
that developed on this medium were thick, long and
fibrous (Figure 2d and e). In vitro-derived plants did not
display any phenotypic variation during subsequent
vegetative development. Up to 75% rooting was achieved
on MS medium with growth regulators.
It is interesting to note that in vitro flowering was
observed after transferring regenerated shoot cultured on
MS medium containing 0.1 mgl -1 IBA and 2 mgl -1 BAP to
rooting medium BAP has been used for most
experiments on in vitro flowering of a number of plants
(Wang et al., 2002). In Rosa hybrida cultivar ‘Meirutral’
and cultivar ‘Fairy’ could flower in propagation medium
containing BAP (Dobres et al., 1998).
Xing et al. (2010) reported rooting of multiplied rose
cultivar rugosa shoots was achieved on medium with IBA
alone, but Razavizadeh and Ehsanpour (2008)
comprised, rooting of Rose hybrida with IBA and NAA
and they resulted NAA (0.1 to 0.5 mgl -1 ) were better.
In conclusion, a micropropagation system for Rosa
(miniature cultivar) has been worked out utilizing single
nodal explants. Micropropagated plants were rooted and
established in vitro successfully. The preliminary result in
this system enables in vitro flowering but requires further
improvement.
ACKNOWLEDGEMENT
This research was financially supported in parts by the
Zarrineh Rooz Tissue Culture Company, Tehran, Iran.
The authors wish to thank the Islamic Azad University of
Qom Laboratory for the use of their equipments.

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Drefahl A, Quoirin MG, Cuquel FL (2007). Micropropagation of Rosa ×
hybrida cv. Vegas via axillary buds. Acta Horticulturae, 751: 407-411.
Hameed N, Shabbir A, Ali A, Bajwa R (2006). In vitro micropropagation
of disease free rose (Rosa indica L.), Mycopath, 4: 35-38.
Hsia CN, Korban SS (1996). Organogenesis and somatic
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Ibrahim R, Debergh PC (2001). Factors controlling high efficiency of
adventitious bud formation and plant regeneration from in vitro leaf
explants of roses (Rosa hybrida). Scientia Horticulturae, 88: 41-57.
Kanchanapoom K, Sakpeth P, Kanchanapoom K (2010). In vitro
flowering of shoots regenerated from cultured nodal explants of Rosa
hybrida cv. 'Heirloom'. Sci. Asia, 36: 161-164.
Khosh-Khui M, Jabbarzadeh Z (2007). Effects of several variables on in
vitro culture of Damask Rose (Rosa damascena Mill.). Acta
Horticulturae. 751: 389-393.
Kim CK, Chung JD, Jee SO, Oh JY (2003). Somatic embryogenesis
from in vitro grown leaf explants of Rosa hybrida L. Afri. J. Plant
Biotechnol., 5(3): 169-172.
Kim SW, Oh SC, In DS, Liu JR (2003). Plant regeneration of rose (Rosa
hybrida) from embryogenic cell-derived protoplasts. Plant Cell Tissue
and Organ Culture, 73: 15-19.
Kintzios S, Manos C, Makri, O (1999). Somatic embryogenesis from
mature leaves of rose (Rosa sp.). Plant Cell. Reports, 18: 467-472.
Kumar A, Sood A, Plani UT, Gupta AK, Plani LMS (2001).
Micropropagation of Rosa damascene Mill. from mature bushes using
thidiazuron, J. Horticult. Sci., 76: 30-34.
Murashige T, Skoog F (1962). A revised medium for rapid growth and
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Rout GR, Mohapatra, A, Mohan Jain S (2006). Tissue culture of
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African Journal of Plant Science Vol. 6(10), pp. 282-289, July, 2012
Available online at http://www.academicjournals.org/ajps
DOI: 10.5897/AJPS12.083
ISSN 1996-0824 ©2012 Academic Journals
Full Length Research Paper
Effect of time of harvest on physiological maturity and
kenaf (Hibiscus canabinus) seed quality
Olasoji J. O. 1 *, A. O. Aluko 1 , O. N. Adeniyan 1 , S. O. Olanipekun 1 , A. A. Olosunde 2
and Okoh J. O. 3
1 Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria.
2 National Centre for Genetic Resources and Biotechnology, Moor Plantation, Ibadan, Nigeria.
3 Department of Plant Breeding and Seed Science, University of Agriculture, PMB 2373, Markurdi, Nigeria.
Accepted 15 May, 2012
Field experiments were carried out between July and December 2010 and 2011 at research station of
the Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation,
Ibadan, to determine the effects of time of harvesting on kenaf seed physiological maturity and quality.
Kenaf seed of 10 genotypes were collected at seven harvesting periods. Seeds were harvested at 5 day
interval from 15 to 45 days after flowering (DAF). Significant variation was observed in all the kenaf
genotypes for all the parameters studied. Maximum seed quality as measured by seed viability,
moisture content, seed mass and germination percentage were obtained at 35 DAF. However, seed
quality of kenaf genotypes reduced thereafter with age and pre-harvest sprouting on mother plant
occurred. Maximum seed weight (mass maturity) was achieved at 35DAF in both years when average
seed moisture contents were 20.58 and 19.28%, respectively. For high seed quality, kenaf is better
harvested at 35 DAF which could be regarded as the point of physiological maturity.
Key words: Kenaf, harvesting period, seed quality, mass maturity, physiological maturity.
INTRODUCTION
Seed development is the period between fertilization and
maximum fresh weight accumulation and seed
maturation begins at the end of seed development and
continues till harvest (Mehta et al., 1993). The seed
reaches its maximum dry weight at physiological maturity.
Studies on seed development and physiological maturity
become important because seeds should be harvested at
proper time to ensure their quality in terms of viability and
vigor. Seed quality can be limited by environmental
conditions both before and after physiological maturity,
the stage of development at which the seed possesses
its maximum dry mass (Indira and Dharmalingam, 1996).
Seeds gradually attain viability and vigor during the
developmental process as seed dry weight is
accumulated. Maximum seed quality may be achieved at
the end of seed filling period (Harington, 1972; Browne,
1978; Tekrony and Hunter, 1995; Tekrony and Egli, 1997)
*Corresponding author. E-mail: juliusolasoji@yahoo.com.
or slightly after this phase (Pieta Filho and Ellis, 1991;
Ellis et al., 1993; Zanakis et al., 1994; Sanhewe and Ellis,
1996; Demir and Samit, 2001; Lehner et al., 2006;
Ghassemi-Golezani and Mazloomi-Oskooyi, 2008;
Ghassemi-Golezani and Hosseinzadeh-Mahootchy,
2009). The end of seed filling phase is described as
physiological maturity (Harington, 1972) or mass maturity
(Ellis and Pieta Filho, 1992). Viability, the least
discriminating measure of seed quality, is quickly gained
during seed development and strongly maintained after
maturity relative to germination ability.
Stage of maturity at harvest is one of the most important
factors that can influence the quality of seeds (Demir
et al., 2008). Harvesting too early may result in low yield
and quality, because of the partial development of
essential structures of seeds (Keller and Kollmann, 1999;
Elias and Copeland, 2001; Ekpong and Sukprakarn,
2008; Wang et al., 2008). Whereas, harvesting too late
may increase the risk of shattering and decrease the
quality of seeds due to ageing. Adverse environmental
conditions such as rainfall or precipitation may also result

in sprouting of seeds on mother plants (Ellis and Pieta
Filho, 1992; Elias and Copeland, 2001; Wang et al.,
2008). Therefore, successful seed production depends
on detection and prompt harvesting at this appropriate
time. This time is a pre-requisite for the production of
maximum number of high quality seeds (Demir and
Balkaya, 2005; Wang et al., 2008).
Physiological maturity is a genotypic character which is
influenced by environmental factors (Gupta and Kole,
1982; Mahesha et al., 2001a). At this point of plant
phenology, seeds attain maximum viability and vigor.
Environmental conditions during seed development and
maturity including temperature, water stress or excessive
rain, nutrients shortage, diseases infection, and pest
pressure influence seed quality (Delouche, 1980). One of
the major constraints facing kenaf productivity in Nigeria
is lack of high quality seeds. Inadequate seeds supply to
farmers as a result of rapid decline of kenaf seed causes
poor viability. Seeds are stored on kenaf plants in the
field after physiological maturity until the proper time of
harvest when suitable seed moisture content is attained.
Any adverse conditions during this period such as heavy
rainfall can affect seed viability. The need to determine
the appropriate harvesting period for kenaf to enhance
and ensure its quality and viability is imperative. Hence
the study tried to determine the time of physiological
maturity of kenaf seed and appropriate time of harvesting
in order to produce qualitative kenaf seed.
MATERIALS AND METHODS
The experiments were carried out at research station of the Institute
of Agricultural Research and Training, Obafemi Awolowo University,
Moor Plantation, Ibadan, in the late humid months of 2010 and
2011 to determine the effects of harvesting stages on physiological
maturity and kenaf seed quality. The trials set up in July both years
in random block design with three replicates. Conventional
cultivation practices were applied. The first harvest was performed
15 days after flowering. Subsequent harvests took place at 5 days
intervals till 45 days after flowering. A total of 7 harvests were
performed. Harvested capsules were carefully shelled and the
seeds extracted. Germination test, seed moisture content and seed
mass determination were performed on the extracted seeds
immediately after harvest. Seed moisture and seed mass were
determined by drying the seed at 105°C for 24 h. Seed viability was
determined using water soaked filter paper. Data were collected on
seed mass and viability. Meteorological data were received from
Institute’s meteorological station. Experimental data were
statistically processed by the analysis of variance and also by
regression analysis.
RESULTS AND DISCUSSION
Mean values for germination percentage at different
harvesting period for both years are shown in Table 1. It
can be seen that viability was lowest at 15 DAF in both
years, but it increased with progressing seed
development. This improvement continued until
maximum seed viability was obtained at 35 days after
Olasoji et al. 283
flowering for all the genotypes. The freshly harvested
kenaf seeds are capable of germinating during the period
between 15 and 30 DAF but the germination capacity is
low. Highest germination percentage was realized in 35
DAF (days after flowering) across all the tested kenaf
genotypes in both years. Mehta et al. (1993) reported that
seeds harvested at 37 days after anthesis recorded
higher germination percentage while seeds harvested at
33DAA showed the lowest germination percentage. From
the study, kenaf seeds reach highest viability values in
both years (PM) at 35 days after flowering, a period when
developing seed reaches its maximum dry weight and the
quality declines thereafter. Seed maturation in kenaf is an
important process during which morphological (seed size
and colour), physiological (dry weight, moisture content
and germination), chemical (oil, protein and
carbohydrate) and functional (vigor and viability) change
from the time of fertilization until the seed are ready for
harvest (Demir and Balkaya, 2005).
Maximum seed quality as measured by seed viability,
moisture content, seed mass and germination percentage
was obtained at the point of mass maturity. These results
agreed with the suggestions that seed quality is at the
maximum at the end of seed filling phase (Harington,
1972; Browne, 1978; Tekrony and Hunter, 1995; Tekrony
and Egli, 1997). Low seed quality at the early stages of
seed development was due to immaturity while the
decline in quality parameter at later stages in both years
caused by seed ageing (Ghassemi-Golezani and
Mazloomi-Oskooyi, 2008) and pre-harvest sprouting
(Figure 3) on mother plant (Ellis and Pieta Filho, 1992;
Elias and Copeland, 2001; Wang et al., 2008). From the
analysis of variance in Table 1, genotype, year and
genotype x year interaction had significant (p < 0.05)
effects on viability at some of the harvesting period.
Throughout the course of development, kenaf seeds
undergo changes in dry weight (Table 2). Between 15
and 35 DAF, dry weight increase very rapidly. The
increase in seed dry weight is associated with the greater
accumulation of photosynthates in to the sink (capsule)
up to 35 DAF after which the growth remained static
which may be due to decrease in photosynthesis and
accumulation of photosynthates (Indira and
Dharmalingam, 1996). The seed dry weight increase to
its maximum at 35 days after flowering and the moisture
content of the seed decline from 70.39% in 2010 and
75.18% in 2011 at 15 days after flowering to a stable
values of about 20% at 35 days after flowering in both
years. There was an overall reduction in seed moisture
content from 15 to 35 DAF as reserve materials
accumulated. Seed moisture content dropped from 70.39
and 75.18% in both years at 15 DAF to 14.39 and
13.78%, respectively at 45 DAF (Table 3). Developing
seeds at early stages of formation have a relatively high
water content compared with the matured seeds. Mehta et
al. (1993) reported that seed harvested at 29 DAA
showed the highest moisture percentage while seed
harvested at 45 DAA showed the lowest moisture

284 Afr. J. Plant Sci.
Table 1. kenaf genotypes seed viability (%) at different harvest dates in 2010/2011.
Genotype Year
G-45
Ex-funtua
Tainung
Ex-Shika
S-72-78-10
A-60-282
Ifeken-100
A-60-284
Ifeken-400
Local line
Average
Days after flowering
15 20 25 30 35 40 45
2010 18.67 18.00 26.67 58.67 94.67 88.00 48.00
2011 0.00 5.00 5.00 33.33 70.00 56.67 38.33
2010 18.67 11.33 32.00 60.00 90.67 78.66 53.33
2011 0.00 11.67 21.67 38.33 76.67 50.00 48.33
2010 17.33 14.00 22.67 62.67 90.67 68.00 50.67
2011 1.33 13.33 23.33 28.33 80.00 45.00 63.33
2010 17.33 22.00 8.00 46.67 86.67 80.00 34.67
2011 0.00 15.00 15.00 36.67 65.00 63.33 60.00
2010 13.33 12.67 37.33 64.00 93.33 88.00 40.00
2011 0.00 10.00 15.00 38.33 71.67 68.33 51.67
2010 12.00 20.00 32.00 48.00 93.33 90.67 48.00
2011 0.00 15.00 25.00 40.00 76.67 61.67 60.00
2010 10.67 19.33 30.67 56.00 92.00 80.00 56.00
2011 0.00 18.33 28.33 50.00 83.33 71.67 40.00
2010 6.67 30.00 24.00 53.33 96.00 78.66 40.00
2011 0.00 8.33 18.33 30.00 65.00 38.33 53.33
2010 4.00 8.00 36.00 53.33 89.33 90.67 38.66
2011 0.00 10.67 16.67 45.00 68.33 55.00 58.33
2010 1.33 9.33 16.00 69.33 96.00 76.00 69.33
2011 0.00 13.33 23.33 51.66 71.67 60.00 65.00
2010 12.00 16.45 26.53 62.37 92.27 81.87 47.87
2011 0.13 12.07 19.17 39.17 72.83 57.00 53.83
F-test
Genotype * * ns ** ns ** **
Year *** ns ** *** *** *** *
G x Y * * ns * ns ns **
***, ** and * significant at 0.001, 0.01 and 0.5% level of probability, respectively. Ns- not significant.
percentage. Moisture content was the highest in H1
stage, that is, seed collected at 30 days after flowering
(DAF) and the lowest moisture content in H3 stage, that
is, at 40 DAF (Mahesha et al., 2001a). The obtained
results (Table 3) indicated that marked reduction in
moisture occurred in the seeds of all the kenaf genotypes
tested after 25 days of observation and moisture dropped
abruptly 35 days after flowering. A drastic reduction in
seed moisture (about 60%) is observed between 30 and
35 DAF. This is exactly the natural desiccation period for
kenaf seed. The results showed that physiological
maturity of field grown kenaf seeds was attained at 35
days after flowering in both years. Local line recorded low
percent reduction in viability after physiological maturity in
both years as compared to other genotypes. At 40 DAF
and thereafter, germination percentage declined in both
years with the exception of Ifeken-400 that recorded an
increase in germination percentage in 2010. Thus,
variation in germination percentage in the kenaf seeds
obtained in two different seasons seems mainly due to

Table 2. Seed mass (g/50 seeds) of kenaf genotypes in 2010 and 2011.
Genotype Year
G-45
Ex-funtua
Tainung
Ex-Shika
S-72-78-10
A-60-282
Ifeken-100
A-60-28
Ifeken-400
Local line
Average
Days after flowering
15 20 25 30 35 40 45
2010 0.61 0.90 1.20 1.23 1.30 1.19 1.29
2011 0.68 0.86 0.98 1.14 1.18 1.17 1.17
2010 0.64 0.97 1.17 1.23 1.34 1.34 1.30
2011 0.71 1.06 1.11 1.23 1.32 1.30 1.33
2010 0.71 0.89 1.17 1.24 1.21 1.23 1.22
2011 0.68 0.94 1.01 1.11 1.27 1.13 1.19
2010 0.76 0.94 1.18 1.36 1.28 1.16 1.20
2011 0.69 0.97 1.26 1.46 1.45 1.26 1.30
2010 0.83 1.01 1.19 1.28 1.31 1.29 1.21
2011 0.69 0.82 0.99 1.31 1.21 1.15 1.27
2010 0.72 0.92 1.15 1.29 1.37 1.25 1.21
2011 0.73 0.89 1.12 1.20 1.32 1.28 1.24
2010 0.73 0.96 1.26 1.30 1.23 1.33 1.28
2011 0.71 0.87 1.06 1.37 1.23 1.37 1.34
2010 0.66 0.93 1.25 1.31 1.37 1.31 1.24
2011 0.61 0.87 1.16 1.30 1.41 1.20 1.26
2010 0.56 0.92 1.22 1.31 1.32 1.35 1.24
2011 0.66 0.81 1.10 1.20 1.28 1.24 1.26
2010 0.71 0.91 1.05 1.23 1.28 1.24 1.22
2011 0.71 1.03 1.01 1.20 1.32 1.24 1.24
2010 0.69 0.94 1.18 1.28 1.30 1.27 1.24
2011 0.69 0.91 1.08 1.25 1.30 1.23 1.26
F-test
Genotype *** * ** *** ** *** *
Year ns ns *** ns ns ns ns
G × Y ** ** * * * ** ns
***, ** and * significant at 0.001, 0.01 and 0.5 % level of probability, respectively. Ns - not significant.
Table 3. Kenaf seed moisture (%) in 2010 and 2011.
Genotype Year
G-45
Ex-funtua
Tainung
Days after flowering
15 20 25 30 35 40 45
2010 74.03 65.13 52.20 46.99 24.55 26.29 13.43
2011 75.33 63.06 56.62 43.44 20.50 12.46 13.77
2010 71.77 64.74 58.74 50.62 16.09 22.29 19.11
2011 74.72 55.37 55.28 52.03 16.00 14.29 15.07
2010 66.21 65.29 56.02 47.91 20.99 25.90 12.67
2011 75.55 60.01 56.00 59.01 22.47 16.13 12.85
Olasoji et al. 285

286 Afr. J. Plant Sci.
Table 3. Contd.
Ex-Shika
S-72-78-10
A-60-282
Ifeken-100
A-60-284
Ifeken-400
Local line
2010 69.92 60.64 57.02 44.41 20.35 14.88 11.94
2011 75.61 59.61 52.62 48.77 16.35 15.95 14.56
2010 68.12 62.46 57.69 49.61 19.02 21.23 18.08
2011 75.86 66.27 55.79 49.60 15.73 19.35 12.04
2010 68.76 58.43 56.16 44.93 15.99 15.31 11.26
2011 73.89 62.12 53.91 55.75 18.07 12.87 10.89
2010 69.26 65.87 55.10 47.67 19.86 17.93 11.91
2011 74.67 61.20 50.58 48.21 23.16 13.64 12.72
2010 72.90 64.51 56.45 50.25 24.89 21.98 21.33
2011 76.57 64.53 53.44 46.03 18.27 13.58 16.17
2010 76.87 62.63 55.62 52.49 28.44 22.30 11.95
2011 76.29 66.42 56.68 49.48 17.27 16.35 16.98
2010 66.08 61.23 55.90 46.29 15.61 19.96 12.26
2011 73.27 56.06 55.09 47.67 24.97 16.29 12.70
Average
F-test
2010
2011
70.39
75.18
63.09
61.47
56.09
54.60
48.11
50.00
20.58
19.28
20.81
15.09
14.39
13.74
Genotype *** ** ns *** *** *** ***
Year *** * ** ** ns *** **
G × Y *** ** ns *** *** *** ns
***, ** and * significant at 0.001, 0.01 and 0.5% level of probability, respectively. Ns - not significant.
Figure 1. Rainfall data during planting.
the variation in environment during seed development
(Figures 1 and 2). Pre-harvest sprouting of seeds on the
mother plants occurred after 35 DAF till the point of
harvest in year 2010 due to high rainfall before the

Temperature (°C)
Figure 2. Maximum and minimum temperature during planting.
Figure 3. Seed germination on kenaf plant.
attainment of harvesting maturity (Figure 3).
The regression analysis showed that the theoretical
maximum viability in all the kenaf genotypes tested was
achieved at seed mass and moisture content of about 1.3
g/50 seeds and 20.00% in both years 2010 and 2011
(Figures 4 and 5). Coefficient of determination (0.715)
was highest between moisture content and seed viability
in 2011.
Conclusion
2010 Min Temp (°C)
2010 Max Temp (°C)
2011 Min Temp (°C)
2011 Max Temp (°C)
Olasoji et al. 287
Highest values of average seed viability were registered
in the genotypes A-60 284 and Local line in 2010 and
Ifeken 400 in 2011. Highest values of average seed
viability were registered in the seed harvested at 35 days
after flowering in both years. Average seed mass was at
the maximum 35 DAF in both years and this could be

288 Afr. J. Plant Sci.
Figure 4. Relationship between seed mass and moisture content on seed viability in 2010.
Figure 5. Relationship between seed mass and moisture content at harvest on seed viability in 2011.
regarded as the point of physiological maturity. For high
seed quality, kenaf is better harvested 35 DAF. After
physiological maturity, local line recorded lowest seed
viability loss in both years. Therefore, this genotype can
be used for future breeding program in kenaf.
ACKNOWLEDGEMENT
This research was supported by research grant from the
Institute of Agricultural Research and Training, Obafemi
Awolowo University, Moor Plantation, Ibadan, Nigeria.
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