M.Sc.

Quality seeds of okra, a popular vegetable crop in Kerala, are in great
demand. An experiment was conducted during the period from January to April 2019
at the Centre for High-tech Horticulture and Precision Farming, Vellanikkara, to
study the effect of precision farming techniques on growth, fruit and seed yield of
okra. The field experiment was laid out in a Randomized Block Design (RBD) with 7
treatments which included two levels of irrigation viz., I1- Drip irrigation at 75%
evapo-transpiration (EP) and I2- Drip irrigation at 100% EP and three levels of
Fertigation viz., F1: 75% RDF (recommended dose of fertilizer), F2:100% RDF and
F3:125% RDF. Fertilizer doses as per POP recommendation for the crop i.e.,
110:35:70 kg NPK/ ha was adjusted based on soil test data. Drip irrigation was given
daily based on PAN evaporation data while fertigation was administered twice a
week. All the drip fertigation plots were mulched with 30 μ silver polythene film. A
plot that was administered flood irrigation along with soil application of fertilizer as
per POP fixed, vide soil test data, served as the control.
The growth parameters of the crop in all the drip fertigation treatments were
significantly superior to control. I1F1 exhibited significant superiority over other
treatments with respect to plant height (84.40 cm), height of the first bearing node
(17.55 cm), LAI (1.19) and fruit set (73.00%). Early flowering (47.33days) was also
observed in this treatment. Between the different levels of irrigation, I1 (irrigation at
75% EP) showed significant increase in plant height (79.23 cm), height of the first
bearing node (14.40 cm), LAI (1.01) and fruit set (70.33%) when compared to I2
(100% EP). I1 also registered earlier flowering (48.89 days) when compared to I2
(53.33 days). However, LAI was not influenced by different levels of irrigation. No
significant difference was exerted by different levels of fertigation on characters like
plant height, LAI, days to 50% flowering and fruit set. However, in the case of first
bearing node, F1 (15.21 cm) followed by F3 (13.90 cm) was superior to F2 (12.95 cm).
Significant interaction effect of irrigation and fertigation levels was evident with
respect to LAI and fruit set.
Fruit characters like length, girth, weight, mature fruit yield per plant and
number of mature fruits per plant were significantly superior in drip fertigation
treatments compared to control. Except I2F3, all other fertigation treatment produced
significantly thicker fruits than the control (1.90 cm). Mature fruit weight was
significantly high in treatments 11F1 (9.10 g) and I1F2 (8.59 g), followed by I2F2
(7.60g). However, mature fruit yield (154.85 g) and number of mature fruits (30.91)
were significantly high in I1F1. Fruit characters like fruit length and girth were not
influenced by different levels of irrigation and fertigation as well as their interaction
effect. However, I1 showed significant increase in fruit weight (8.09 g), mature fruit
yield (116.49 g) and number of fruits (25.67g) when compared to I2. Mature fruit
weight (8.20 g & 8.09 g) and number of fruits (24.19 & 22.98) were on par in F1 and
F2. Among the interactions, I1F1 showed superior performance in fruit weight, mature
fruit yield/plant and number of fruits/plant.
With respect to seed characters like number of seeds per fruit, seed weight
/fruit, seed yield per plant, 100 seed weight, seed germination and seedling vigour
index, the drip fertigation treatments were significantly superior to control. Between
the irrigation levels, I1 significantly increased number of seeds/fruit, seed yield/plant
and seedling root length when compared to I2. But seedling vigour index was
significantly higher in I2 (2504) compared to I1 (2424). However, characters like seed
weight/fruit, 100 seed weight, 100 seed volume, germination, moisture content, hard
seed content and seedling shoot length were not affected by irrigation levels. Among
the fertigation levels, seed germination and seedling vigour index was highest in F1
(93.33 % and 2914) while F2 showed increased number of seeds/fruit (42.87) whereas
F3 showed increased 100 seed weight (6.70g), seedling shoot length (22.68 cm) and
low hard seed content (8.48%). Seed weight and seed yield were not influence by
fertigation levels. Significant interaction effect of irrigation and fertigation levels
were evident in number of seeds/fruit, 100 seed weight, seed germination and
seedling root length. I1F1 was found to be significantly superior for most seed traits
studied. But seedling vigour index was significantly higher in I2F1 (2947).
Storage studies were conducted with seeds of okra variety, Arka Anamika
procured from Centre for High-tech Horticulture and Precision Farming,
Vellanikkara. The seeds were treated with polykote (synthetic polymer) @ 5 and 10
ml per kg of seed along with plant protection chemicals viz., carbendazim-mancozeb
(Saaf- 2g/kg of seed) and bifenthrin (0.1%) or biocontrol agent- Trichoderma viridae
(4g/kg of seed). Untreated seeds served as control. The seeds were packed in 700
gauge polyethylene bags and stored under both cold (refrigerated) and ambient
conditions and seed quality parameters assessed at bimonthly intervals.
With the advancement of storage period, germination declined irrespective of
the treatments in both the storage conditions. Throughout the storage period,
performance of treated seeds was found to be significantly superior over control. At
the end of twelve months of storage, higher seed germination was recorded in seeds
treated with polykote (10ml) + carbendazim- mancozeb (2g) + bifenthrin (0.1%) both
under cold (75.33%) and ambient (71.33%) conditions. Lower values were recorded
in untreated control (60.33 per cent under cold storage and 56.33 under ambient
storage). Both seedling shoot length and root length were significantly higher in
treatment with polykote (10ml) + carbendazim- mancozeb (2g) + bifenthrin (0.1%)
both under cold and ambient conditions. Seedling dry weight was also significantly
higher in the same treatment in the cold storage while in the ambient condition, there
was no significant difference among the treatments. The EC of seed leachate and seed
microflora also showed the same trend with very low value for polykote (10ml)
+carbendazim- mancozeb (2g) + bifenthrin (0.1%) in both cold and ambient
conditions.
From the study it can be concluded that drip irrigation at 75% EP and 75% of
RDF along with mulch, is best for seed production in okra. Storage of seeds treated
with polykote (10ml) + carbendazim- mancozeb (2g) + bifenthrin (0.1%) in cold is
recommended to ensure minimum seed certification standards.