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ThesisItem Open Access Genetic diversity of Dimocarpus longan Lour., in Southern Western Ghats(Department of Forest Biology and Tree Improvement,College of Forestry, Vellanikkara, 2022) Devika, P S; KAU; Manju Elizabeth, PLongan (Dimocarpus longan Lour.), is an important commercially cultivated fruit tree, belonging to the family Sapindaceae. It is commonly known as dragon-eye. In Kerala, it is known by the names chempoovam, mullai etc. It is widely cultivatedin many Asian countries like China, Thailand, and Taiwan etc. Recently many other countries including India, Sri Lanka etc. have started cultivating longan tree as a commercial fruit tree. Longan is used as a traditional medicine in China due to its high medicinal and nutraceutical value. The global demand for longan fruit has hiked rapidly due to its sweet taste and nutritional value. Fruit consist of a white edible juicy aril which is surrounded by a leathery pericarp. The fruit is rich in various bioactive polyphenols, vitamin C, volatile compounds, minerals, amino acids, proteins, fats, carbohydrates etc. Longan leaf, fruit pericarp, seed and pulp were used for extracting various polyphenols. Extracts from various parts of longan have shown pharmaceutical properties like antioxidance, anti-tyrosinase, anti-cancerous, anti-glycated, immunomodulatory activity, antihypertensive etc. Thus the importance of fruit can also be emphasized due to its richness in nutritional value. The longan tree is a subtropical fruit tree native to the southern regions of China and Indo-Burma. D. longan is indigenous to India's Western Ghats, ranging from Konkan to Tinnevelly. Other distributions in India include Eastern Bengal and Western Peninsular regions. In the Western Ghats region of Kerala, longan is a species widely distributed in evergreen forests. There is a small distribution in the semi-evergreen forests of Kerala as well. The diversity of indigenous longan populations in Western Ghats has never been studied before. In this study, morphological and genetic diversity of longan populations from six different locations in the Western Ghats regions of Kerala were selected. Among these six locations, three were located in the north of Palghat gap and three were in the South ii of Palghat gap. Morphological parameters like crown shape, branching pattern, tree height, tree girth, leaf length and leaf width was considered for studying the morphological diversity. Results from morphological traits revealed that the population from Meppadi region from north of Palghat gap stood different from other longan populations. Cluster analysis conducted using UGPMA method based on the morphological traits showed that population from Mankulam was closely related to the Meppadi population. The populations from six locations were divided into two major clusters. ISSR primers were used to investigate the genetic diversity existing among the six populations. 15 ISSR primers screened from total of 19 primers were used to amplify the DNA sample from different longan populations. Average polymorphism rate of 69.51% was observed. Matrix data was obtained and hierarchical dendrogram was produced using UGPMA method in NTsys pc 2.02 and DARwin software which clusters the populations into two major groups. Jaccard’s dissimilarity index was calculated using R software and the values ranged from 0.00 to 0.51. Genetic relation existing between the natural populations of longan in Kerala, cultivated longan cultivars and litchi were identified. Cluster analysis using UGPMA method pooled different populations into four major clusters and study proved that litchi is genetically more related to the cultivated longan variety rather than the wild populations. This is the first report on the molecular characterization of D. longan from Western Ghats regions in India. The results from this research study can provide valuable information to distinguish, classify and identify the origin of longan populations in India and can be applied for future breeding programs.ThesisItem Embargo Soil nutrient dynamics in a second rotation monocropped teak plantations(Department of Forest Biology and Tree Improvement, College of Forestry, Vellanikkara, 2022) Santhosh, D T; KAU; Santhoshkumar, A VTeak is considered the most valuable tropical timber species and is known as the "King of Timber". Kerala has 76,710 ha of pure teak plantation and 14,440 ha of teak plus softwood planting, accounting for 49.08 and 9.24 percent of the state's total plantation area, respectively. Kerala's teak plantations productivity has been declining and a large-scale drop in teak plantation productivity in the replanted teak regions, referred to as ‘Second rotation decline’ is being observed. In this context, a field study on “Soil nutrient dynamics in a second rotation monocropped teak plantations” was conducted in selected plantations from Thrissur and Chalakkudy Forest Divisions to investigate the quantity and intensity of soil nutrients among second rotation teak plantations. The study site was divided into five age classes (0-10, 10-20, 20-30, 30-40 and 40-50 years) and 6 replications (sample plots) were laid out in each age class forming a total of 30 sample plots (6 sample plots x 5 age classes). Sample plots of size 24m x 24m were laid randomly and total tree height and girth at breast height were measured in the field. Surface soil (0-30cm) samples were collected from each plot. Teak foliage sampling was done by collecting the index leaf (second fully opened leaf from the bud). Ground vegetation sampling was carried out by harvesting all vegetation from randomly laid out 1m x 1m plots from each sample unit. Soil sampling was also carried out from open barren lands from both the forest divisions. The collected soil was analysed for physical properties like particle size distribution/texture and chemical properties like soil pH, CEC, exchangeable bases, extractable acidity, organic carbon, quantity and intensity factors of N, P, K, Ca, Mg, S, Na, Fe, Zn, Cu, Mn, Al, Ni, Cd, Pb and also the critical limits with reference to teak. Quantity of C, N, P and K were estimated from teak foliage and ground vegetation following standard procedures. The results showed that among the plantations studied in Thrissur and Chalakudy divisions, there were differences in terms of soil chemical properties in 100 plantations of different age classes. However, definite pattern of concentration of elements with respect to the age of the plantations was lacking. The intensity factors of nutrients too showed no pattern or trend with reference to the age of the teak plantations. The variation in ion concentration in soil solution was not influenced by the quantity or labile pool of the element. The soils from teak plantations were observed to have more concentration of nutrients compared to barren land. All the observed soil parameters were well within the range required for the optimal growth of teak. However, there was also variation in terms of the concentration of the elements. Attempts to relate soil parameters to site productivity yielded no relevant associations, implying that the decline in productivity may be due to poor management rather than nutrient depletion. There was significant management inconsistency among the plantations, which significantly influenced the potential utilization of site resources for optimal teak development. Significant variation in the content of C, N, P and K were observed in teak foliage of various age classes. A decrease in N, P, and K content was observed in the foliage with an increase in age. The content of C, N, P and K in the ground vegetation samples of different age classes showed no pattern in trend with respect to the age of the teak plantations. Further extensive studies on the soils from teak plantations in the state in terms of ion activity to obtain better knowledge in terms of nutrient deficiency and toxicity with a particular focus on improving productivity of teak plantations is also required. The results of this study also point to an imperative necessity to study other factors apart from soil that affect teak productivity.ThesisItem Open Access Progeny testing and genetic diversity analysis in plus trees of Melia dubia Cav.(Department of Forest Biology and Tree Improvement, College of Forestry, Vellanikkara, 2022) Shifin S, Ravuther; KAU; Binu N, KamalolbhavanThe present study titled “Progeny testing and genetic diversity analysis in plus trees of Melia dubia Cav.” was carried out from 2020 to 2021 with the objective of progeny evaluation in 25 half sib plus trees identified from different part of Kerala, by studying the growth performance of its seed progeny planted at college of forestry germplasm field. The study also includes exploring the genetic diversity of these 25 plus tree seed progenies along with analysing the caryophyllene content, one of the economically important phytochemical compounds present in M. dubia. The plus tree seed progeny differed significantly in morphological traits like height, collar girth, volume and physiological parameters like photosynthetic and transpiration rate, stomatal conductance, chlorophyll content and relative water content. The progeny FCV-MD-03 of Tholpetty in Wayanad district performed better in growth parameters viz., height (5.61 m), collar girth (0.42 m) and tree volume of (0.017 m3 ). The variability study indicated that the morphological trait (volume) and physiological trait (stomatal conductance) exhibited higher PCV and GCV. From the heritability estimation it was observed that the most heritable morphological trait was collar girth followed by the plant height. For the physiological parameter, transpiration rate (0.91) was the most heritable trait followed by the chlorophyll content. These morphological and physiological traits were positively correlated implicating the significance of physiological parameters as source to identify better progeny. Path analysis on morphological trait has showed that the collar girth had the highest positive direct effect on the plant volume. Genetic variation study in 25 plus tree progenies using ISSR primer produced 164 amplicons which estimates viz., percentage of polymorphism (68%), polymorphism information content (0.70 to 0.83), Nei’s gene diversity (31%). The dendrogram obtained by using UPGMA classified the 25 accession of M. dubia into 2 distinct clusters. Cluster I constitute population from Wayanad and the rest of the 136 population in cluster II. Based on the genetic variation observed, superior seed sources can be identified and tree improvement programme could be developed for the conservation and further development of M. dubia. Standardization of HPLC for the quantification of caryophyllene phytochemical in M dubia was studied. Significant variation was observed for the total caryophyllene content for the different accession of M dubia seed progeny. The maximum quantity was observed in FCV-MD-08 (16.4 %) of Pothundy in Palghat district followed by FCV-MD-3 of Tholpetty in Wayanad.