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ThesisItem Open Access Refinement of in vitro propagation technique in pineapple var. mauritius and mass multiplication of elite clones(Department of pomology and floriculture, College of horticulture,Vellanikkara, 1996) Jo Jose C; Radha TThe studies on refinement of in vitro propagation technique in pineapple var. Mauritius and mass multiplication of elite clones were conducted at Kerala Horticulture Development Programme, Kerala Agricultural University, Vellanikkara during 1993 – ’95. Based on the survey conducted at the major pineapple growing areas, namely, Vazhakulam – Muvattupuzha regions of Ernakulam district, five elite clones of Mauritius variety with higher yield and other desirable fruit characters were selected propagules from the selected clones were planted at Vellanikkara for taking explants for their mass multiplication through refined in vitro propagation techniques. For shoot tip explants, treatment with emisan 0.1 per cent for 35 minutes followed with mercuric chloride 0.1 per cent for 10 minutes and for lateral bud explants treatment with emisan 0.1 per cent for 10 minutes followed by 0.1 per cent mercuric chloride for three minutes was found to be the ideal surface sterilization treatment. Culture establishment and growth initiation of shoot tip explants from different sources (suckers, crowns and slips) and lateral bud explants were better in MS medium supplemented with BAP 3 and 4 mg 1-1. Explants from shoot tips were found to be better than those from lateral buds for achieving faster culture establishment and growth initiation. Enhanced release of axillary buds was the maximum in Ms medium containing BAP 4.0 mg 1-1. Among the different subculture stages, multiple axillary bud production was higher in second suculture stage. Addition of casein hydrolysate 100.0 mg 1-1 in to the medium with BAP 4.0 mg 1-1 favoured the production of axillary buds. Adventitious bud initiation from sucker shoot tips was fastest in MS medium supplemented with BAP 5.0 mg 1-1 + NAA 1.0 or 0.5 mg 1-1. For adventitious bud production from lateral buds, treatment with BAP 7.5 mg 1-1 + NAA 1.0 mg 1-1 was the best. Proliferation rate of adventitious buds was maximum in MS medium supplemented with BAP 4.0 mg 1-1 + NAA 0.5 or 1.0 mg 1-1. Rate of multiplication of adventitious buds was higher in liquid medium under shake culture condition, than in solid medium. Faster shoot regeneration and increased vigour of the shoots were resulted in growth regulator free MS medium. However, highest number of shoots were produced in MS medium supplemented with BAP 1.0 mg 1-1. Liquid medium under shake culture condition was found superior of solid media with respect to initiation of shoots and mean number of shoots, however, the latter resulted in longer shoots. In vitro rooting was fastest in MS medium, without any growth regulator, which produced longer and normal roots with secondaries and root hairs. Though addition of NAA (3 mg 1-1) resulted in increased number of roots, they were very short and hair like. Stationary liquid medium was found superior to solidThesisItem Open Access Vegetative, Floral and fruit characters in mangosteen (Garcinia mangostana L.)(Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, 1996) Ajay Alex; KAU; Sarah, T GeorgeThe present investigations on the growth habit, phases of growth, flowering and floral biology, fruit development, seed viability and storage life of mangosteen were carried out in the Department of Pomology and Floriculture, College of Horticulture, during the period 1994-96. The studies indicated that shoot growth in mangosteen coincided with the main flushing season from June to August and with a second one from January to February. Maximum shoot growth was observed during July. The growth of the tree was slow, with an extension growth of 6.91 cm in an year. The tree had a monopodial orthotropic trunk meristem which showed continuous growth. Laterals exhibited plagiotropy, sympodial growth and sylleptic branching habit. Leaf arrangement was spiral in the seedling stage but distichous on the branches of mature tree. Emerging leaves which were purplish red, later changed to dark green. The flowering season was from December to January. But development was completed in 28 days. Flowers were female and borne terminally on branchlets either singly or in groups of two to four. Flower drop was meager. Peak anthesis period was between 17.30 and 18.00 hours. Flowers had four scarlet red sepals and four yellow petals each having imbricate aestivation. Androecium consisted of 18-20 staminodes. Gynoecium was syncarpous with five to seven carpels having single ovule in each locule on axile placentation. Style was short and had a five to seven fid capitate stigma at its end. Anthers failed to dehisce until flower opening but a few showed signs of dehiscence after anthesis. Stigma showed no signs of receptivity. Anthers produced numerous non viable pollen grains which failed to germinate in vitro. Different methods of pollination had no effect on fruit set. Initial set was high but a fruit drop of 41 per cent occurred during first month. Though fruit development was parthenocarpic and seed development parthenogenetic, seeds produced were viable. Therefore, mangosteen can be considered as an obligate agamosperm where proembryos developing from integuments of embryosac mature into embryos. Pulp development took place from 42nd day onwards. Average weight of ripened fruit was 100 g. The percentage contribution of pulp towards total fruit weight at ripening stage was 33.00 per cent as against 62.30 and 4.70 per cent in the case of rind and seed, respectively. Chemical composition of pulp showed a decreasing trend. Total sugars, reducing sugars, non reducing sugars and sugar : acid ratio increased upto harvest. Season of harvest coincided with South West monsoon. Stage of harvest was identified as 90 days after fruitset. Such fruits ripened normally in two days at ambient temperature and showed no difference in quality as compared to that of tree ripened fruit. At this stage, 25 per cent of the fruit skin developed a purple colour and scar formed at the stalk end was smooth, without any exudation of gum. Mechanical injury should be avoided during harvesting and handling to save fruits from Transluscent Flesh Disorder. Yield varied from 650 to 3350 fruits/tree. Number of segments, which was same as that of stigmatic lobes, ranged from four to seven. However, number of viable seeds ranged from zero to three. Fruits caught in the rain were severely affected with gamboges, a disorder, which accounted to about 33.82 per cent fruit loss. Exudation of yellow gum from the rind was the characteristic symptom. The fruit pulp also became yellow, gummy, corky, bitter in taste and inedible. Biochemical analysis showed that ripened fruit contained water 76.57, protein 0.5, citric acid 0.32, total sugars 17.02, reducing sugars 3.22, non reducing sugars 13.80, nitrogen 0.28, phosphorus 0.01, potassium 0.13, calcium 0.01 and magnesium 0.24 on percentage basis. Sugar : acid ratio, TSS and ascorbic acid content was 53.18, 27.00 0brix and 5 mg/100 g, respectively. β carotene was only in traces. Fruits stored under refrigerated conditions showed no quality deterioration and fruit loss even after one month of storage. Fruits kept in bamboo baskets lasted for a fortnight. Keeping quality of fruits even without any treatment was more than a week. During storage TSS, sugars and sugar: acid ratio decreased, whereas acidity increased with the storage period. Seeds varied in size and shape. Viability was very high when sown immediately after harvest. Storage reduced the viability and was completely lost by 35 days of storage. Seeds took 20 days for germination. Germination was hypogeal with single seedlings arising normally, but 10 per cent polyembryony with 2-4 seedlings/seed was also noticed.
