Journal
Journal of Applied Horticulture, 21(1): 81-84, 2019
Appl
Seed development and maturation in African marigold (Tagetes
erecta L.)
C.N. Murali*1, S.K. Jain1, M.A. Joshi1 and Anjula Pandey2
ICAR-Indian Agricultural Research Institute, New Delhi-110012. 2ICAR-National Bureau of Plant Genetic Resources,
New Delhi-110012. *E-mail: muralicnagri@gmail.com
1
Abstract
Marigold is an annual flower crop and it is mainly cultivated and propagated through seeds. Seed quality is the key issue in flower
seed industry. Indeterminate flowering in marigold leads to differential maturity of seeds resulting in wide differences in the seed
quality, major constraints in marigold seed production are optimum stage of physiological maturity and stage of seed harvest. Hence,
a study was undertaken to identify the optimum stages of seed maturity in African marigold varieties. The experimental results showed
that, on-set of germination starts at 8-10 DFA; and quality seeds in marigold can be harvested between 46-48 DFA. Besides, total oil
content in seeds recorded of about 35 % during physiological maturity and of about 33% at harvest maturity; its content also varied
with genotype as well as stage of seed maturity.
Key words: Seed development, Tagetes seeds, on-set of germination, physiological maturity, harvest maturity and total oil in seeds.
Introduction
Marigold (Tagetes spp L.), a member of Asteraceae family, is an
important annual flower crop native to Central America (Nehr,
1968). African marigold (Tagetes erecta) and French marigold
(Tagetes patula), the two commonly found species in marigold,
African type is noted for large flower heads and French types
are well known for their smaller flowers. Marigold is mainly
cultivated and propagated through seeds hence the seed quality
is the issue in the seed industry to meet the desired standards and
to compete with the global seed trade. It becomes imperative
to evolve a strategy to produce quality seeds and make them
available in time at a reasonable price to the farming community.
The improvement of flower seed industries in developed
countries like India requires high quality seeds. In India, the
mass production of the flowers is limited due to poor seed quality
(Gornik and Grzesik, 2005), which is majorly due to improper
seed development and maturation under unfavourable weather
conditions, as well as by short period of day light (Gornik and
Grzesik, 2002; Janakiram, 2004).
Indeterminate flowering of marigold leads to differential maturity
of seeds resulting in wide difference in seed quality (Pramila,
2010). Major constraints in marigold quality seed production
are optimum stage of physiological maturity and stage of harvest
(Mathad et al, 2005). Physiological maturity is the stage at which
the quality of the seed is at its maximum; early harvested seeds
results in immature seeds with low vigour, whereas late harvest
ends in seed deterioration and seed loss (Still and Bradford,
1998). It is needless to emphasize that good quality seed is a
pre-requisite for optimum returns from the seed crop. Hence, a
detailed study is the needed to determine the optimum stage of
physiological maturity and stage of harvesting so as to obtain
the quality seeds with maximum germination and vigour. Hence,
the present study was undertaken with an objective to study the
pattern of seed development and maturation in selected varieties
of African marigold.
Materials and methods
To study the seed development and maturation, the African
marigold cultivars Pusa Basanti Gainda (PBG) and Pusa Narangi
Gainda (PNG) were raised during rabi 2015-16 and 2016-17
in 60 cm (row) x 45 cm (plant) spacing, following RBD with
standard agronomic practices. The flower buds were tagged in
each genotype everyday throughout the flowering period. The
developing seeds were harvested at seven days interval i.e. 0 to 49
days from anthesis (DFA) and tested for seed quality parameters
like, fresh weight, dry weight, seed moisture content and seed
germination in the first year of crop growth. Subsequently, during
second year of crop growth, the flower buds were harvested at
periodic intervals of one day to confirm the on-set of germination
(0-14 days), and physiological and harvest maturity (35-49 days).
For determining seed moisture content, the fresh and dry weight
of flower buds were estimated following ISTA rules (ISTA, 2015)
in each genotype using three replicates, ten flower buds in each
replicate were weighed a fresh and dried at 80 °C for 24 hrs in
an electric hot air oven.
a. Seed germination (%): The seed germination was tested using
four replicates of 50 seeds each, which were placed on pre-soaked
filter paper in a Petri-plates and were kept at 200~30 0C. The final
count was taken on 14 day from seed incubation (ISTA, 2015).
b. Seedling growth (cm): To determine the seedling growth,
ten normal seedlings on 14th day from standard germination test
in each replicate were taken randomly; and the seedling growth
was measured from the tip of the primary root to the tip of the
primary leaf.
c. Seedling dry weight (mg): Estimation of seedling dry weight
was done using ten normal seedlings, randomly drawn from
Journal of Applied Horticulture (www.horticultureresearch.net)
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Seed development and maturation in African marigold
standard germination test, on 14 day in each replicate, which
were dried using hot air oven at 80o ± 2 °C for 24 hrs, cooled over
silica gel and weighed to assess the biomass.
d. Seedling vigour index: Seedling vigour indices (SVI-I and
SVI-II) were calculated following Abdul-Baki and Anderson
(1973).
e. Estimation of total oil in seeds (%): The total oil in seeds
was estimated during seed maturity (at physiological and harvest
maturity) using Soxhelt method as described by AOAC (2016), A
known quantity (5g) of seed sample was grinded into fine powder
using sodium sulphate (Na2SO4) and subjected it into the Soxhelt
apparatus; in which sample was boiled with a petroleum ether (80
0
C) up to 14 hrs. At the end, distilled the solvent completely and
repeatedly heated the sample until constant weight was recorded.
The obtained oil content (g/g) was expressed in percentage (%).
Results and discussion
The results on fresh weight, dry weight, seed moisture content,
and seed quality parameters during 2015-16 are presented in table
1. The flower buds harvested at periodic intervals of seven days
and tested for fresh weight, dry weight and seed quality. During
2015-16 fresh weight among the genotypes is increased from
0.69 g to a maximum of 3.48 g at 42 DFA; followed a decrease
in it up to 2.26 g at final interval (49 DFA), and dry weight
increased from 0.11 g and reached up to 2.18 g and reaches its
minimum and constant at harvest maturity. At the initial stage of
seed development, seed moisture content among the genotypes
was very high (83.51 to 86.61 %) which declined to about 18 %
at seed maturity. During in the first year of seed development,
seed germination was witnessed during 14 DFP and gradually
germination quality in in seeds increased and it reached up to
88 % during 35 DFA at which seed quality attains its maximum
since seeds accumulated with all the available reserves required
for germination.
During the subsequent year of seed crop growth (2016-17),
developing seeds were harvested at a periodic interval of one
day (0-14 & 35-49 days, respectively) and similar observations
were made (table 2 and 3) to confirm on-set of germination,
and physiological and harvest maturity, respectively. On-set of
germination started during 8-9 DFA and seed moisture content
during on-set of germination was recorded about 82 % in both
varieties. Physiological maturity was noticed with higher seed
germination 86 to 88 % during 42-44 DFA and it associated
with higher fresh weight of 3.21 to 3.47 and dry weights of 1.98
to 2.18 g. Harvest maturity started noticing after 46 DFA and it
was confirmed with negligible decline in dry weight; and when
dry weight was about to coincide with dry weight in a few days.
Physiological maturity in seeds is to recapture a high reproducing
capacity and it usually coincides with attainment of maximum dry
weight (Natarajan and Srimathi, 2008), during which the flow of
nutrients from mother plant to the seed freezes. Seed maturation
is a period from fertilization to harvest during which the seed
Table 1. Fresh weight (g), dry weight (g), moisture content (%) of flower buds and seed quality during seed development (2015-16)
Parameter*
Days from anthesis
Genotype
0
7
14
21
28
35
42
49
Fresh weight* (g)
PBG
0.69
1.77
2.18
2.47
2.86
3.12
3.21
2.26
PNG
0.78
1.82
2.86
3.21
3.37
3.43
3.48
2.68
Dry weight* (g)
PBG
0.11
0.35
0.53
0.79
1.24
1.67
1.98
1.86
PNG
0.10
0.24
0.81
1.01
1.43
1.87
2.18
2.18
Moisture content (%) PBG
83.51
80.04
75.53
68.18
56.60
46.42
38.21
17.54
PNG
86.61
86.67
71.68
68.49
57.42
45.33
37.31
18.86
Seed germination1
PBG
0.00
0.00
21.00
36.00
74.00
80.00
86.00
78.00
(%)
PNG
0.00
0.00
17.00
34.00
57.00
78.00
88.00
79.00
Seedling growth2
PBG
0.00
0.00
4.18
6.21
9.81
10.84
11.96
11.76
(cm)
PNG
0.00
0.00
4.26
6.58
10.54
12.19
13.48
12.69
Seedling dry weight2 PBG
0.00
0.00
14.21
17.53
21.77
23.06
23.95
22.16
(mg)
PNG
0.00
0.00
14.48
17.61
22.11
23.19
24.78
23.25
SVI-I
PBG
0.00
0.00
89.11
223.48
732.72
852.87
1019.53
909.08
PNG
0.00
0.00
73.61
219.05
588.79
958.75
1186.07
999.24
SVI-II
PBG
0.00
0.00
302.72
631.24
1626.27
1814.21
2044.31
1713.41
PNG
0.00
0.00
251.01
587.29
1237.43
1824.19
2179.17
1829.51
LSD
P=0.05
0.088
0.085
0.059
0.068
3.603
3.180
3.337
3.443
0.625
0.722
0.549
0.600
49.175
74.159
100.168
91.607
Where, PBG: Pusa Basanti Gainda; PNG: Pusa Narangi Gainda; *Average of three replicate of 10 flower buds in each replicate; 1Average of four
replicates from 50 seeds in each replicate; 2Average of four replicates from 10 seedlings in each replicate.
Table 2. Fresh weight (g), dry weight (g), moisture content (%) and seed germination during seed development (2016-17)
Parameter
Genotype
Days from anthesis (DFA)
0
1
2
3
4
5
6
7
8
9
10
11
12
PBG 84.13 84.09 83.00 82.78 82.36 81.55 79.73 80.20 79.12 78.07 77.01 76.77 76.86
1
Moisture (%)
PNG 87.54 87.18 87.44 87.12 87.77 87.72 87.46 86.84 83.82 82.19 80.09 76.62 73.03
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.00 6.00 9.00 14.0 17.0
Seed germination2 PBG
(%)
PNG
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.00 5.00 7.00 10.0
13
76.16
72.77
20.0
12.0
14
75.58
71.56
21.0
17.0
LSD
P=0.05
4.189
2.532
1.952
2.130
Where, PBG: Pusa Basanti Gainda; PNG: Pusa Narangi Gainda; 1Average of three replicates from 10 flower buds in each replicate; 2Average of four
replicates from 50 seeds in each replicate
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Seed development and maturation in African marigold
83
Table 3. Fresh weight (g), dry weight (g), moisture content (%) and seed germination during seed maturation (2016-17)
Parameter
Genotype
Days from anthesis
Fresh weight1
(g)
Dry weight1
(g)
Moisture
content (%)
Seed
germination2
(%)
PBG
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
LSD
P=0.05
3.12
3.12
3.13
3.13
3.14
3.17
3.19
3.21
3.17
2.84
2.68
2.57
2.48
2.35
2.26
0.052
PNG
3.42
3.42
3.43
3.45
3.45
3.47
3.48
3.48
3.49
3.47
3.41
3.24
2.85
2.76
2.68
0.047
PBG
1.67
1.72
1.76
1.81
1.87
1.91
1.94
1.98
1.96
1.94
1.92
1.88
1.88
1.86
1.86
0.039
PNG
1.87
1.91
1.96
1.99
2.03
2.09
2.14
2.18
2.21
2.21
2.20
2.19
2.19
2.18
2.18
0.032
PBG
46.35 44.87 43.77 42.06 40.45 39.58 39.25 38.21 38.16 31.69 28.34 26.71 24.09 20.82 17.54 1.762
PNG
45.32 44.05 42.85 42.27 41.16 39.83 38.50 37.31 36.77 36.21 35.55 32.40 23.06 20.89 18.86 1.399
PBG
80.00 82.00 82.00 84.00 84.00 86.00 86.00 86.00 86.00 86.00 82.00 82.00 78.00 78.00 78.00 3.615
PNG
78.00 81.00 82.00 84.00 84.00 86.00 88.00 88.00 88.00 88.00 84.00 84.00 80.00 79.00 79.00 4.108
Where, PBG: Pusa Basanti Gainda; PNG: Pusa Narangi Gainda; 1Average of three replicates from 10 flower buds in each replicate; 2Average of four
replicates from 50 seeds in each replicate
Table 4. Total oil content (%) during seed maturation
Genotypes
Physiological Harvest maturity
maturity
Mean
PBG
35.47
31.26
33.37
PNG
36.83
33.10
34.97
Mean
36.15
32.18
SE(m) ±
CD @ 0.05
Genotype
0.407
1.231
Stage
0.288
0.870
Genotype x Stage
0.576
NS
Factors
Where, PBG: Pusa Basanti Gainda; PNG: Pusa Narangi Gainda
crop undergoes a physiological, biochemical and morphological
changes in seeds (Delouche, 1973). To reap the maximum quality
in seeds, understanding the optimum stage of seed harvest is
crucial. In our results, maximum germination was achieved
during 42-44 DFA in African marigold; but at this stage, seeds
possess a higher moisture content, which it is not advisable to
safe harvest. As the seed maturity advances, moisture content
in seeds decreases significantly in marigold (Shivakumar et al,
2003). Hence, matured seeds of marigold can be safely harvested
on 46 DFA in African types. Thus, our results are in conformity
with Pramila et al (2008), who reported that African marigold
seeds harvested between 120 to 125 days after transplanting, when
seeds exhibits higher seed quality parameters. Similar results were
reported by Hugar (1997) in Gaillardia; Natarajan and Srimathi
(2008) in petunia. The present results wrt harvest maturity are in
similar line with the results obtained by Shivakumar et al (2003)
in marigold, and Adetunji (1991) in Sunflower; Mathad et al
(2008) in china aster.
The total oil content in seeds varies significantly among genotypes
and also at different stages of seed maturity. Among genotypes,
PNG recorded highest oil content in seeds (36.83 % and 33.10
%) followed by PBG (35.47 and 31.26 %) during physiological
and harvest maturity accordingly. As the seed heads matures, the
oil content and its composition increases and it starts decreasing
as it proceeds to the harvest maturity (Baydar & Erbas, 2005).
Experimental results in total oil content is in conformity with
Martin et al, 2005 who reported that oil content increased
significantly and reached its maximum (about 45 %) during
45 DFA and after which it gradually decreased significantly in
sunflower seeds. In our study, oil content significantly differed
among the genotypes at two different stages of seed maturity.
Thus, it provides a biochemical basis for seed maturation in
marigold. However, total oil content in marigold seeds is reporting
here for the first time it may be further studied elaborately
particularly on seed oil content.
From the present study (over two years), it can be concluded that
on-set of germination starts between 8 to 10 DFA and matured
seeds of marigold can be safely harvested between 46-48 DFA
in African types. Further, total oil content in developing seeds
provided a biochemical basis for the seed maturation in marigold
and the oil quantity obtained was significantly high alike in
Asteraceae crops like sunflower and calendula.
Acknowledgement
The authors thank Dr. K. Ali, Division of Plant Bio-Chemistry,
ICAR-Indian Agricultural Research Institute, New Delhi for his
assistance during Soxhlet method of seed oil estimation.
References
Abdul-Baki, A.A. and J.D. Anderson, 1973. Vigour determination in
soybean seed by multiple criteria. Crop Sci., 13: 630-633.
Adetunji, I.D., 1991. Effect of harvest date on seed quality and viability
of sunflower in semi- arid tropics. Seed Sci. Technol., 19: 571-80.
Arunachalam, M., K. Sivasubramanian, K. Angamuthu and C.P.
Thiagarajan, 1995. Studies on fruit and seed maturation in balsam
genotypes. The Orissa J. Hort., 23(1 & 2): 54-58.
Baydar, H. and S. Erbas, 2005. Influence of seed development and seed
position on oil, fattyacids and total tocopherol contents in sunflower
(Helianthus annuus L). Turk J. Agric., 29: 179-86.
Bosma, T.L., K.E. Conway, J.M. Dole, N.O. Maness, 2003. Sowing
dates and priming influence African marigold emergence. Hort.
Technology, 13: 487-493.
Delouche, J.C. 1973. Seed maturation In: Seed Production Manual NSC
and Rockfeller foundation. p.162-165.
Gornik K and Grzesik M. 2005. China aster plant growth, seed yield and
quality as influenced by Asahi SL treatment. Folia Horticulturae,
17(2): 119-127.
Gornik, K. and Grzesik M. 2002. Effect of Asahi SL on China aster
‘Aleksandra’ seed yield germination and some metabolic events
Acta Physiol Plant, 5: 379-383.
Hugar, A.H. 1997. Influence of spacing, nitrogen and growth regulators
on growth, flower and seed yield in gaillardia cv Pictafouger.
Ph.D.Diss., UAS Dharwad, 1997. 339 pp.
ISTA, 2015. International Rules for Seed Testing. p. 306-308.
Journal of Applied Horticulture (www.horticultureresearch.net)
84
Seed development and maturation in African marigold
Janakiram, T. 2004. Heterosis and hybrid seed production in ornamental
crops In: Souvenir of National Symposium on Harnessing Heterosis
in Crop Plants, Varanasi. p.143-153.
Martin, R, S. Montgomery, S. Thompson, S. Phan and S. Im, 2015.
Sunflower Production. Bull., p.14-18. Australian Centre for
International Agricultural Research., Australia.
Mathad, R.C., B.S. Vyakaranahal and V.K. Deshpande, 2008. Influence
of planting dates and picking stages on seed yield and quality in
aster [Callistephus chinensis (L.) nees] genotypes. Indian J. Agric.
Res., 42(3): 224-227.
Mathad, R.C., D. Laximinarayana, R. Sathyanarayana, and M.
Raveendra. 2005. Correlation and path coefficient analysis in African
marigold (Tagetes erecta L.). The Karnataka J. Hort., 1(3): 22-27
Natarajan, K and P. Srimathi, 2008. Studies on seed development and
maturation in petunia. Res. J. Agric & Biol. Sci., 4(5): 585-590.
Neher, R.T. 1968.The ethnobotany of Tagetes. Econ. Bot., 22 (4): 317325.
Pramila, C.K. 2010. Studies on seed technological aspects in marigold
(Tagetes spp L.). Ph.D. Diss., UAS Bengaluru, 2010.327 pp.
Rakesh C, B.S. Mathad, Vyakaranahal and S.D. Raikar,2009. Influence
of maturity stages on seed yield and quality of China Aster
(Callistephus chinensis L. Nees) genotypes. Indian J. Agric. Res.,
43 (2): 95-100.
Shivakumar, C.M., B.M. Gowda, M. Shekhargouda, I.S. Kurdikeri and
Dharmatti, 2003. Effect of stage of harvesting on seed quality in
African marigold (Tagetes erecta L.), Seed Res., 31(1): 105-106.
Vijaykumar, A. 2005. Seed development and maturation in marigold, cv
African giant. The Orissa J. Hort., 33(1): 46-48.
Received: October, 2018; Revised: November, 2018; Accepted: November, 2018
Journal of Applied Horticulture (www.horticultureresearch.net)