PhD Thesis

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End date: 1989Subject: search.filters.subject.Banana

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    Studies on certain chemical constituents of banana leaves in relation to incidence of leaf spot diseases: A note on the fungi occurring on banana
    (Division of Plant Pathology ,Agricultural College and Research Institute ,Vellayani, Trivandrum, 1966) Chandrasekharan Nair, M K; Sam Raj, J
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    Intraclonal variations and nutritional studies in banana cv. Palayankodan
    (Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1985) Rajeevan, P K; Mohanakumaran, N
    The investigations were carried out at the Banana Research Station, Kannara, during 1981-84 in the banana cv. 'Palayankodan'. Twenty four accessions were subjected to detailed analysis with respect to growth, yield and quality. The plants of the accessions differed significantly with regard to height and girth of pseudostem during the later stages of growth , both in the plant crop and in ratoon 1. Significant differences observed in the number of functional leaves were not consistent. Area of the third leaf at shooting varied significantly in all the three crops. The trend in variation between the crops, however, was not consistent. Interval of leaf production, total number of leaves produced and the density of stomata in the upper surface of the leaf lamina showed significant differences. The duration from planting to shooting in ratoon 1 alone varied significantly. The plant crop took more time than ratoon 1 and ratoon 2 to come to harvest. The content of nutrient elements in the index leaf did not exhibit significant variations. The reactionof the accessions to the important pest (rhizome weevil) and diseases (bunchytop and Sigatoke) varied considerably.
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    Bio-ecology of the cyst nematode infecting banana
    (Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1989) Job Sathyakumar Charles; Venkitesan, T S
    Pathogenicity of the cyst nematode on banana cv. Nendran carried out revealed that the nematode can affect crop growth and yield at lowest initial inoculum of 100 cyst3 per plant. However, the threshold level of initial inoculum of 800 to 1,000 cysts per plant the growth, yield and quality of fruits were considerably reduced. An initial inoculum of 100 to 1,000 viable cysts per plant at planting time could reduce bunch weight by 20.5?£ to 56.6?4. The nematode Infection was observed to affect quality of fruits by increasing acidity and reducing total sugars. This nematode attacks the minute tertiary feeder roots and not observed to attack the fleshy roots and rhizome portions. The attacked feeder roots turn black in colour and detach easily. The final nematode population revealed that there was significant build up in the density of population. The increase ranged from 15*59 to 35.18 per gram root and from 1,168 to 3,188 in 100 gram soil. A significant negative correlation was found to exist with plant growth parameters, bunch characteristics and root weight with the initial inoculum levels of cyst nematode population.
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    Cytotaxonomical studies on banana cultivars
    (Department of Pomology and Floriculture and Landscaping, College of Horticulture, Vellanikkara, 1984) Valsalakumari, P K; Sivaraman Nair, P C
    Variability in banana are wide and complex with different degrees of expression of the characters of the parental species, Musa acuminata and Musa balbisiana. Commercial cultivars are many, ranging in levels of productivity and quality characters. Investigations were conducted at the College of Horticulture, Kerala Agricultural University, Vellanikkara, Trichur during 1981-83 on 100 cultivars of banana to study the cytotaxonomical aspects. Studies on morphological characters, taxonomic scoring and chromosome number revealed that many of the cultivars were identical and ultimately the cultivars were confined to 64 distinct ones. The taxonomic scoring did not indicate the ploidy. Eight cultivars with the scores of triploids, were identified as diploids. The quantitative, quality and pollen characters showed a significant variation among the cultivars. The characters were influenced by the ploidy and the genomic constitution. The presence of ‘B’ genome increased plant height and girth, leaves per plant, leaf area per plant and petiole length. Musa balbisiana (BB) recorded the highest values for all the above characters. The triploids were more vigorous than the diploids and the tetraploids as indicated by their higher growth rates. The triploids were also better than the other groups for bunch and finger characters. Among them, the triploids of hybrid origin were better for bunch characters while the Musa acuminata triploid group (AAA) was superior to the other groups for finger characters. Longer pedicel was a characteristic feature of Musa balbisiana( BB). The genomic constitution of the cultivars influenced the contents of total soluble solids, sugars and acids in fruits, more than the ploidy. Musa acuminata group AAA, had the highest sugar/acid ratio. Studies on pollen viability, size and production in cultivars revealed the possibility of including a few of them as male parents in the banana hybridization programme. Forty of the cultivars studied were polleniferous. Pollen viability and production were more in pure Musa acuminata and Musa balbisiana groups than in groups of hybrid origin. Musa acuminata cultivars had larger pollen grains than cultivars belonging to the other genomic groups.Estimates of genotypic and phenotypic coefficients of variation, heritability in the broad sense, genetic advance and genetic gain for the 26 characters indicated the scope for selection among the cultivars. Petiole length, pulp/peel ratio on volume basis, weight and volume of fruit showed higher heritability values combined with high genetic gain. Estimation of genetic divergence among the cultivars showed that the cultivars ‘Mannan’ and ‘Pacha chingan’, belonging to the genomic group AAB, were the closest and a Musa acuminata cultivar, ‘Harichal’ (AAA) and Musa balbisiana (BB) were the farthest. The 62 cultivars were grouped into eight homogeneous clusters. Similar clustering pattern was obtained in the canonical analysis also. The study revealed the predominance of the cultivars of the hybrid origin, with different degrees of expression of the characters of the parental species, in the South Indian bananas. The taxonomic scoring system was not always appropriate to find out the ploidy of the cultivars. The study also indicated the scope for selection among the cultivars and the possibility of inclusion of the cultivars with viable pollen as male parents in the hybridization programme.
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    Production potential of cassava-based cropping systems
    (Department of Agronomy, College of Horticulture, Vellanikkara, 1986) Ashokan, P K; Sreedharan, C
    A series of field experiments were conducted during the years 1983-84 and 1984-85 at College of Horticulture, Kerala Agricultural University, Trichur, to evaluate some of the cassava based intercropping systems and to investigate the interspecific interactions. There were three field trials and two micro plot trials. In the first field trial, the treatments were factorial combinations of two planing geometries of cassava viz., paired row and square cluster planting geometries of cassava viz., paired row and square cluster planting and four intercropping practices viz., intercropping with colocasia, elephant foot yam, banana and no intercropping. In the second field trial, there wer 12 treatments derived from the factorial combinations of three geometries of planting (paired row, square cluster and triangular cluster) and four intercropping practices (growing a floor crop of cowpea, groundnut, elephant foot yam and not growing any floor crop) in a cassava + banana intercropping system. In the third field trial, the possibility of growing two crops of groundnut in sequence ( Kharif and cowpea and/or Rabi) and the fertilizer requirements of intercrops were studied. All the three field trials were laid out in randomised Block Design and replicated thrice. In one of the micro-plot trials, 32P absorption by the component species in a cassava + banana + elephant foot yam cassava planted in square cluster was studied. polyculture with In the other micro plot trial 32P absorption by cassava and groundnut under the situations of cassava planted in paired row-ridge, mound and flat bed methods were studied. These two microplot trials were laid out in Completely Randomized Design with three replications. Paired row and square clustered planting of cassava gave similar yields as that of normal method when the plant population was the same. Intercropping cassava in square cluster with elephant foot yam resulted in maximum yield of cassava (20.1 t/ha) and elephant foot yam (10.6 t/ha). Banana and colocasia were also found to be successful as intercrops in cassava planted in paired row or square cluster. Intercropping with elephant foot yam and banana resulted in higher yield of cassava. The intercrops colocasia and elephant foot yam recorded lesser yields than the sole crops whereas in intercrop banana such difference was not observed. The maximum LER of 1.81 was obtained in cassava + banana cropping system. The cassava + elephant foot yam intercropping removed 133, 11, 107, 46, 12 and 18 kg/ha of N, P, K, Ca, Mg and S respectively wheras in the cassava + banana combination the corresponding figures were 227, 14, 236, 70, 16 and 11 kg/ha. From the two year trials, the cassava + banana + elephant foot yam cropping system with cassava planted in square cluster (9070 plants/ha) / triangular cluster (6800 plants/ha) was found to be the most productive and economical cropping system. Elephant foot yam was found to be shade tolerant and the yield reduction in intercropped situation was only marginal. The floor crops of cowpea and groundnut were successful in the first year. The land equivalent ratio in cassava + banana + elephant foot yam intercropping was 1.7 and this cropping system gave a net profit of Rs. 13300 per hectare. The N, P, K, Ca, Mg and S removal in a cassava + banana + elephant foot yam cropping system was found to be 198, 24, 200, 166, 34 and 19 kg/ha respectively. Sequential intercropping in paired row planted cassava was not successful, but growing groundnut and red gram simultaneously in the interspace was found to be successful; groundnut was harvested after four months, red gram after eight months and cassava after nine months. The fertilizer requirements of intercrop cowpea and groundnut were found to be only about 60-90 per cent of the sole crop recommendation and the optimum doses of N, P and K worked out were 6, 18 and 18 kg/ha for cowpea and 4, 30 and 30 kg/ha for groundnut. The main crop of cassava also was benefited by the application of fertilizers to the intercrops. The organic carbon and total nitrogen content of soil were reduced in two or three component intercropping systems by the two year cropping practices. The exchangeable P, K, Ca, Mg and SO 4 increased in situations where legmues alone were intercopped and decreased when banana and a floor crop of cowpea, groundnut or elephant foot yam were intercropped. The micronutrient status of the soil was not remarkably changed by the two season cropping. The intercrop and sole crop systems were not different in their influence on the post crop nutrient status of the soil. The radiophosphorus applied to the root zone of any of the components in the mixed cropping system cassava + banana + elephant foot yam with cassava in square cluster planting was absorbed not only by the treated plants but also by the surrounding species. Banana was the most dominant component in this polyculture. In the cassava + groundnut cropping system, cassava was the most dominant component, accumulating about 90 to 98 per cent of the 32P applied to cassava on mounds/ridges and about 50 percent of that applied to the groundnut root zone in the interspaces. Groundnut root system was small and less active and was able to derive only about 2 to 5 per cent of the 32P applied to cassava mounds. It was also deduced that the root interactions were stronger when all the components of the intercropping systems were a longer duration and it would be mild with legume intercrops of short duration.