Crop Production
Agrotechniques
In Udhayam banana, the plants at wider spacing of 2.1 X 2.4m and with a fertilizer dose of 300:400g N&K plant-1 exhibited the earliest flowering (413.7 days), maturity (137.2 days) and the highest bunch weight (35.7 kg).

Uniform growth of tissue culture Udhayam banana plants at 2.1 X 2.4m spacing

Udhayam banana plants under wet land system of cultivation

Udhayam bunch weighing 36.5 kg with 18 hands and 296 fingers

  • In Robusta, paired row planting system (1.5x1.5x2.0m) recorded a total yield of 65.91 tonnes/ha that was 28.3% higher than the conventional planting system (47.24 tonnes/ha).
  • Fertigation with 75% RDF recorded significantly more bunch weight (18.5 kg) and yield (57.7 t/ha) and was on par with 100% RDF.

Ratoon crop of Robusta banana two suckers per pit at 1.8 X 3.6m spacing

Ratoon crop of Robusta banana three suckers per pit at 1.8 X 3.6m spacing

  • In Grand Naine (AAA), the plants grown under the paired row planting system recorded a total yield of 52.7 t/ha, which was 29.8% higher than conventional planting system.
  • In Grand Naine (AAA), the plants grown under the paired row planting system recorded a total yield of In Red Banana (AAA), significantly higher total yield of 28.5 t/ha was recorded in paired row planting system as against 20.8 t/ha obtained under conventional planting.
  • In Grand Naine (AAA), the plants grown under the paired row planting system recorded a total yield of In a trial on high density planting with fertigation in Grand Naine banana, the plants at 2m X 3m spacing and 75% RDF fertigation took significantly lesser time to the time taken for maturity (96.1 days) for maturity and the highest bunch weight (15.5 kg) among the plants under high density planting.
Soil Science
Increasing the nutrient use efficiency through the soil amendments
  • Under sodic soil conditions, application of 2 kg gypsum/plant + 15 kg FYM/plant + 120% recommended K, exhibited no salt injury symptoms, had highest bunch weight (10.3kg) and had maximized Potential Buffering Capacity (PBC) of K throughout the crop growth period, while the control plot recorded average bunch weight of 5.9kg.
Exploring alternate sources of potassium for banana cultivation
  • Application of cement kiln flue dust at 0.5 kg plant-1 and distillery effluent at 75 kL ha-1 with 60 per cent recommended K (as commercially available KCl) recorded the highest bunch weight (13.59 kg), which is 25 per cent more than that (10.85 kg) at 100 per cent recommended commercial K fertilizer alone.
Increasing the nutrient use efficiency through proper nutrient tailoring
  • Based on the soil initial test values, different fertilizer adjustment equations were developed at this centre for commercially important bananas like Nendran, Rasthali, Ney Poovan, Poovan and Karpuravalli to calculate the required quantities of different fertilizers by following the ‘Targeted yield concept’ of Ramamoorthy (1967).
Nendran
  • FN = (29.8 x T) – (0.97 x SN) – (0.62 x ON
  • FP = (5.45 x T) – (1.24 x SP) – (0.42 x OP)
  • FK = (57.92 x T) – (0.92 x SK) – (0.80 x OK)
Rasthali
  • FN = (18.34 x T) – (0.92 x SN) – (0.29 x ON)
  • FP = (2.77 x T) – (0.74 x SP) – (0.63 x OP)
  • FK = (39.85 x T) – (0.78 x SK) – (0.51 x OK)
Ney Poovan
  • FN = (19.0 x T) – (0.84 x SN) – (0.28 x ON)
  • FP = (2.41 x T) – (0.76 x SP) – (0.20 x OP)
  • FK = (33.10 x T) – (0.50 x SK) – (0.45 x OK)
Poovan
  • FN = (26.7 x T) – (0.76 x SN) – (0.29 x ON)
  • FP = (3.61 x T) – (0.73 x SP) – (0.38 x OP)
  • FK = (41.98 x T) – (0.96 x SK) – (0.49 x OK)
Karpuravalli
  • FN = (21.6 x T) – (0.83 x SN) – (0.29 x ON)
  • FP = (3.21 x T) – (0.76 x SP) – (0.22 x OP)
  • FK = (22.4 x T) – (0.59 x SK) – (0.32 x OK)
Here, FN, FP and FK are nitrogen (N), phosphorus (P2O5) and potassium (K2O) requirement (kg/ha) of banana cultivated in one hectare, respectively, through fertilizers. T is the target (tons/ha) of banana yield. SN, SP and SK are quantity (kg/ha) of nitrogen (N), phosphorus (P2O5) and potassium (K2O) already existing in the soil, before application of fertilizer. ON, OP and OK are quantity (kg/ha) of nitrogen (N), phosphorus (P2O5) and potassium (K2O) contributed from the recommended dose of organic manures applied to banana crop. Once the initial soil NPK contents are estimated through soil testing and the banana yield target is fixed, the NPK balance to be applied through fertilizers to achieve the fixed target can be calculated by using these equations.
Leaf nutrient analysis and remediation
  • A Diagnosis Recommendation Integrated System (DRIS) chart has been developed for monitoring the status of N, P and K in ‘Nendran’ banana by developing norms of DRIS.

DRIS chart for Nendran banana with respect to leaf concentrations of N, P and K

Effect of micronutrients with and without sulphur application on banana under high pH soil
  • In Ney Poovan banana under micronutrient trial in high pH soil, foliar application of 0.5% solution each of FeSO4, ZnSO4and Borax without sulphur recorded the highest bunch weight of 15.4 kg (36.3% more than control) with net additional profit of Rs.61750 per ha. Soil application of 5g FeSO4 along and foliar application of 0.5% solution each of ZnSO4 and Borax with sulphur recorded the highest bunch weight of 16.1 kg (41.2% more than control) with net additional profit of Rs.69750 per ha.
Utilization of human urine as liquid organic manure in integrated nutrient management in banana cultivation
  • The highest bunch (Poovan) weight of 23.9kg was recorded with the application of 50 litres of human urine per plant along with 75% recommended dose of K alone. Application of 100% recommended NPK alone (without urine) recorded a bunch weight of 21kg. Application of 50 litres of urine per plant along with 75% recommended dose of K alone could accrue an additional net profit of Rs. 45,175/- per hectare when compared to 100% recommended NPK alone, ie., normally grown Poovan banana without urine application.
Plant Physiology
Optimization of leaf number at flowering for normal fruit development
  • Keeping optimum number of leaves is desirable at flowering for normal fruit development without affecting quality. Thereby we can reduce the transpirational water loss and contain the spread of leaf spot disease through reduction of spore inoculums.
  • Robusta, Karpuravalli, Ney Poovan, Saba, Poovan, Nendran 8-10 leaves and for Rasthali 6 leaves are minimum number required at flowering for normal fruit development without affecting starch content and fruit quality. Lesser than these prescribed number of leaves affected the bunch weight.

De-leafing in Rasthali (AAB) at flowering did not affect the bunch development

Physiology diploid and triploid banana
  • Ney Poovan (AB), a diploid cultivar, recorded significantly higher carbon assimilation than the triploid cultivar Karpuravalli (ABB).The Ney Poovan’s leaf area, leaf area index, stomatal frequency, stomatal conductance and transpiration was maintained on par with Karpuravalli.
  • The physiological parameters, i.e. chlorophyll content, photosynthesis, stomatal conductance and transpiration recorded during vegetative stage in 2nd to 5th fully opened leaves from top to down were not significant.
  • The diploid variety, Ney Poovan, recorded higher Chl a, Chl b and total Chl than the triploid variety during vegetative stage.
Studies on influence of ploidy level on root characters of Banana:
  • The thickness and number of roots varies with ploidy level. The diploid cultivar, Ney Poovan (AB), produced more and thin roots than triploid varieties (Rasthali, (AAB), and Karpuravalli (ABB)
  • Root observations were recorded in the field grown banana at seventh month revealed that, the number of roots varied from 360-382 roots/plant & 490-502 roots / plant and the thickness varied from 0.3 to 0.6cm & 1.1 to 0.6 cm in Ney Poovan (AB) and Karpuravalli (ABB) respectively.
Source and sink relationship:
  • To analyse and work out the percentage of different sources for bunch development was analysed through, cloth wrapping and total leaf pruning in different cultivars. It was found that current photosynthesis (leaf photosynthesis) is very important as it contributes around 52 % for Rasthali and Ney Poovan, where as in Karpuravalli and Saba pre-flowering storage is very important as it contributes around 66%. The bunch photosynthesis contribution for finger development was around 3.14 – 7.07% in all the tested varieties.
  • There was genotypic difference among the banana cultivars in contribution of pre-anthesis corm starch to the developing fruit. The percentage starch mobilized from corm to developing fruit ranged from 73.81 % to 83.52%.
Genotypic difference in starch composition
  • The fresh green banana fruit pulp (90% maturity) contains 80-85% of starch on dry weight basis. The amylose content recorded more than 35% in Nendran (AAB) Saba (ABB) & Monthan (ABB) than other dessert cultivars (Robusta, Rasthali, Poovan, Neypoovan) recorded in the range of 25-29 %.
  • Nendran corm was analysed for N, P, K, Ca and Mg at 3rd, 5th, 7th, months, & at flowering and harvest. In all the phenological stages the nutrients content were higher in the inner core of the corm than outer core. The NPK and Mg content (%) were found to be higher at flowering, where as the Calcium content was higher at 7th month after planting.
Post Harvest Physiology
  • Rasthali, un-ripened green banana fruits (80% maturity) stored for a week at 10oC, became chilling injured. The chilling injured green fruits blackened and failed to ripen where as normal ripening was observed when it was stored at 13.5oC
  • In Poovan (AAB) green banana fruits was stored at 12oC and 10oC for three weeks. The TSS, titrable acidity (decreased) and pH (increased) of the pulp affected by the low temperature treatment and duration of the treatment.
  • When the fruits of Rasthali and Grand Nain subjected to cold storage at 10oC for 21 days, there was no significant reduction in polygalactuornase and cellulase activity and the activities were on par with 13.5o Cold stored fruits.
  • The beta amylase activity of green banana fruit mostly reduced under low temperature storage (10oC) condition in most of the cultivars. From the genomic DNA of Rasthali, Grand Nain and Nendran BMY 8 gene was amplified and the size of amplicon was 900 bp.
Drought Tolerance of Banana
  • Drought tolerant banana genotypes were identified based on Leaf Water Retention Capacity. Drought tolerant genotypes viz. Nattu Poovan (AB) Thella Chakarakeli (AAA) Teraben (Mysore AAB) Mannan (AAB) Musa Balbisiana (BB) Ladan (AAB) Erode Kai (ABB) Pisang Berlin (AA). The susceptible genotypes are Pisang Seribu (AAB),False Horn Plantain (AAB)Nendran (AAB).
  • The chlorophyll stability index, membrane stability index and epicuticular wax , rate of leaf emergence, leaf senescence, RWC, stomatal conductance can used for drought tolerance screening.
  • When water stress was imposed at flowering for one month, the yield was reduced drastically Among the cultivars tested, Robusta found was more sensitive. The fruit length (11-14%) and circumference (5.75-16%) also decreased among the tested cultivars.

Drought symptom : Down folding of leaves along the midrib and premature yellowing of leaves

Salt tolerance of Banana
  • In salt affected field (EC1:2.5 = 3.56, pH 8.1) Saba produced normal fruit and bunch development, where as in Robusta and Nendran, poor finger and bunch development recorded.

salt tolerant Saba

Salt susceptible cultivar Robusta: Salt stress affects finger development

  • Among all Ney Poovan, Nendran and Robusta accumulated more Na+ ions (0.25 to 0.625%) than Saba and Karpuravalli (0.001%). However, in all the varieties Na+ ions were found to more in leaf midribs. In corm Karpuravalli accumulated significantly less Na+ ions (0.001%) compared to all other varieties (0.375 to 1.875%). At harvest Na+ ions in the peel and pulp of middle hands of Saba Karpuravalli banana fingers recorded less ( 0.001 to 0.25%) than other varieties ( 0.375 to 0.5%). Mg and Ca were mobilized from banana corm .in salt tolerant varieties unlike susceptible cultivars.
  • Saba and Karpuravalli maintained higher K+/Na+ ratio in lamina and leaf midribs at flowering as well as at harvest. The tolerant varieties maintained higher K+/Na+ ratio in the lamina as well as in the midrib at flowering as well as at harvest..
Biochemistry
Biochemical Mechanism of Banana Resistance to Nematode
  • Pratylenchus coffeae (root lesion nematode) induced the activity of phenol-metabolizing (peroxidase and polyphenol oxidase), stress related (phenylalanine ammonia lyase) and lignin synthesizing (cinnamyl alcohol dehydrogenase) enzymes in roots of nematode-resistant banana varieties viz., Anaikomban and Yangambi km5 and susceptible cultivars viz., Robusta and Nendran to several folds with peaking of activity at 7 days after inoculation. The activities were many-times higher in resistant var. Anaikomban, Yangambi km5 than in susceptible cvs. Robusta and Nendran.
  • The nematode infection induced the accumulation of total phenolics, proanthocyanidins, tannins and lignins in the roots peaking at 7 days with accumulation of higher amounts in resistant var. Anaikomban, Yangambi km5 than in susceptible cvs. Robusta and Nendran. The accumulation of lignin was 380 μg/g in Anaikomban and Yangambi km5, whereas it was only 72 μg/g in Nendran and Robusta at 7 days after inoculation of the root lesion nematode.
  • Ten phenolic metabolites were found in both nematode-resistant (Anaikomban and Yangambi km5) and -susceptible (Robusta and Nendran) banana varieties and the contents of metabolites were higher in resistant cultivars than in susceptible bananas and were higher in roots of nematode-inoculated resistant and susceptible banana varieties.
  • Seven major proanthocyanidin compounds from the roots at seven days after inoculation of Pratylenchus coffeae were found in both resistant and susceptible bananas and the amounts of individual proanthocyanidins were higher in resistant banana varieties and in roots of inoculated bananas than in uninoculated control.
  • The total phenolics and individual phenolic metabolites showed difference in the nematode infected mature roots with many-times higher contents in cortex tissues than in vascular tissues.


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