Nutrient management for pineapple (Ananas cosmosus L.)C.V. Amritha
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Date
2019
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Department of Fruit Science, College of Horticulture Vellanikkara
Abstract
Amritha, is the pineapple hybrid released from the Pineapple Research Centre, Vellanikkara, under KAU. The present study entitled “Nutrient management for pineapple (Ananas comosus L.) cv. Amritha” was conducted for standardizing the optimum nutrient doses for ensuring high productivity. When grown under the existing POP recommendation of KAU the fruit weight was varying from 0.5 - 1 kg per plant. Therefore, there is a need to develop optimum nutrient doses for ensuring higher productivity of pineapple cv. Amritha. Experiment was conducted with six treatments viz., T1 - POP recommendation of KAU (8:4:8 N, P2O5, K2O g plant⁻¹), T2 - Modified based on soil test results (9.39:11.45:11.36 N, P2O5, K2O g plant⁻¹), T3 - 25 per cent higher than the modified POP based on soil test results (11.7:14.31:14.31 N, P2O5, K2O g plant⁻¹), T4 - 50 per cent higher than the modified POP based on soil test results (14.08: 17.17: 17.03 N, P2O5, K2O g plant⁻¹), T5 - 75 per cent higher than the modified POP based on soil test results (16.4:20.03:19.13 N, P2O5, K2O g plant⁻¹), and T6 - adhoc organic POP.
Length of ‘D’ leaf showed significant difference among the treatments after eight months of planting. T6 recorded the maximum length of ‘D’ leaf (44.3 cm) and was on par with T1 (41.1 cm) and T5 (40.9 cm). This was continued in ninth, tenth, eleventh and twelfth months after planting. Significant difference was observed in ‘D’ leaf area among the treatments after nine months of planting. T6 recorded the maximum ‘D’ leaf area at tenth (113.77 cm2), eleventh (128.70 cm2) and twelfth (155.20 cm2) months after planting and was significantly superior over other treatments. Application of different levels of nutrients had no significant effect on plant height, number of leaves per plant, breadth of ‘D’ leaf, leaf area index and leaf production rate.
Treatments, T5 and T6 took 6 ¹/₂ months after planting to attain physiological maturity whereas, other treatments attained physiological maturity at a period of seven months after planting. Days for initiation of flowering was minimum in T5 (39.2 days) and was significantly different from other treatments.
In case of days for 50 per cent flowering, T5 recorded the minimum value (47.2 days) and was on par with T4 (49.4 days).
Significant difference was observed among the treatments for fruit weight and was highest in T5 (0.985 kg). The maximum length, girth and breadth of fruit was recorded in T5 (14.15 cm), (30.79 cm) and (30.33 cm) respectively. In case of length/breadth ratio T5 (0.48) recorded the highest value which was on par with T6 (0.46). Higher taper ratio values were recorded by T3 (1.041) and T2 (1.040). With respect to the yield per hectare, maximum value (51.99 t/ha) was recorded by T5 which was significantly superior. T5 recorded the highest peel weight (105.74 g), pulp weight (0.402 kg) and crown weight (118.54 g). The minimum peel/pulp ratio was observed in T5 (0.26). There was no significant difference among treatments for days for fruit maturity, harvest index, root:shoot ratio, crop duration and shelf life.
On evaluating the quality parameters of fruits, TSS was found to be highest in T5 (15.30 ˚Brix) and was on par with T4 (14.60 ˚Brix). In case of other parameters like titratable acidity, total sugars, reducing sugars, non reducing sugars, sugar/acid ratio, fibre content and ascorbic acid content, the treatments were found to be non significant. The overall sensory score was found to be highest in T6 (69.18) and was followed by T5 (64.12). The highest B:C ratio was calculated for T5 (4.59).
Analysis of soil after the harvest of the crop revealed that the values for soil pH, soil EC, organic carbon, available N, P and K were found to be elevated. N, P and K content in the plant and fruit had no significant difference.
In the present study early flowering was observed in T5 (75 per cent higher than the modified POP based on soil test results) which in turn resulted in early fruit set and harvesting in the treatment. Highest fruit weight T5 (0.98 kg) and yield per hectare (51.99 t/ha) was also recorded in T5 (75 per cent higher than the modified POP based on soil test results). On sensory evaluation, Adhoc organic POP (T6) was found to be superior and was followed by T5.
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