M Sc

The study entitled “ Standardization of growing medium and
growth retardants for compact growth of potted African marigold” was carried out
in the Department of Floriculture and Landscape Architecture, College of
Agriculture, Vellanikkara during 2020-2021. The objective of the study was
standardization of growing medium and growth retardants for regulating growth of
potted African marigold for display purpose.
The experiment consisted of five different media viz; cocopeat
(60%) + vermicompost (20%) + vermiculite (10 %) + rice husk (10%) [M1],
cocopeat (60%) + FYM (20%) + vermiculite (10%) + rice husk (10%) [M2],
cocopeat (40%) + soil (20%) + vermicompost (20%) + vermiculite (10%) + rice
husk(10%) [M3], cocopeat (40%) + soil (20%) + FYM (20%) + vermiculite (10%)
+ rice husk (10%) [M4] and soil: FYM: sand (1:1:1) [M5] and two growth
retardants in three different levels viz; cycocel [750 ppm (GR1), 1000 ppm (GR2)
and 1500 ppm (GR3)] and paclobutrazol [30 ppm (GR4), 60 ppm (GR5) and 90
ppm (GR6)] along with a control group of each media without application of growth
retardants. Four week old seedling of marigold variety ‘Double Orange’ was used
for the study. Observations on vegetative characters, Floral characters as well as the
nutrient status of growing media were recorded.
With regard to vegetative characters, growing media, growth
retardants and interaction between growing media and growth retardants had
significant influence. Shortest plants were observed in M1 [cocopeat (60%) +
vermicompost (20%) + vermiculite (10 %) + rice husk (10%)] and among the
growth retardants, paclobutrazol at 90 ppm [GR6] was found to produce short
plants. The same treatment were also found superior with respect to plant spread,
number of branches and number of leaves. Regarding interaction effect an
improvement in all vegetative parameters was observed in M4 [cocopeat (40%) +
soil (20%) +FYM (20%) + vermiculite (10%) + rice husk (10%)] x GR6
[paclobutrazol 90 ppm]. Significant effects of growing media could be observed
in floral characters and M4 was found superior with respect to floral characters
Viz; number of flowers per plant (10.14), flower diameter (4.61 cm)and field life of
individual flowers (9.21 days). M2 was found superior in terms of other floral
ABSTRACT
characters viz; days taken for first flower bud emergence and days taken from
flower bud initiation to flower opening.
With respect to the influence of growth retardants on floral
characters, a greater number of flowers per plant (9.50), flower diameter (4.22),
flowering duration (96 days) and field life of individual flowers were observed by
the application of paclobutrazol at 90 ppm. Growing medium and growth retardant
interaction had significant influence on floral characters. Lowest days for first
flower bud emergence and from flower bud initiation to flower opening were
observed in M2 [cocopeat (60%) + FYM (20%) + vermiculite (10%) + rice husk
(10%)] x GR1 [cycocel 750 ppm]. Number of flowers per plant was highest in M4 x
GR6, M5 x GR6 and M4 x GR5 [paclobutrazol 60 ppm]. Treatment combination
M4 x GR6, M5 x GR6 and M4 x GR4 [paclobutrazol 30 ppm] were superior with
respect to flower diameter and field life of individual flowers.
Analysis of growing media before and after the experiment for
differentphysio- chemical properties revealed that M1 had the lowest bulk density
(g/cm3
) highest porosity (%) and water holding capacity (%).The chemical
properties pH and EC of all the media were found in the favourable range [pH - 5.8-
6.2; EC<1.5dS/m] both before and after the experiment. Available N, P, K before
and after the experiment was found highest in M4 .Plant nutrient content (NPK),
Total chlorophyll content and uptake of nitrogen and potassium by plants were also
found higher in M4.
From the overall performance, it could be noted that the vegetative
parameters viz; plant spread, number of branches and number of leaves as well as
floral parameters such as number of flowers, size of flowers and field life of
individual flowers were in desirable range in treatment combination M4 x GR6.
Hence the medium M4 [cocopeat (40%) + soil (20%) + FYM (20%) + vermiculite
(10%) + rice husk (10%)] along with application of paclobutrazol 90 ppm [GR6] 20
and 35 days after pinching can be recommended for compact growth of potted
Africanmarigold