1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Variability of Mangosteen (Garcinia mangostana L.) in Kerala(Department of Fruit Science, College of Agriculture, Vellayani, 2023-01-13) Ananya P S.; Rafeekher MThe study entitled ‘Variability of mangosteen (Garcinia mangostana L.) in Kerala’ was conducted under Department of Fruit Science, College of Agriculture, Vellayani during the period of October 2020 to December 2021 with an objective of assessing the variability and identification of elite clones in mangosteen grown in Kerala. Since Wayanad and Thrissur districts represent the major mangosteen growing areas of Kerala, assessment of the variability of the crop was done in different agro ecological units (AEUs) of Wayanad (AEU 15 and AEU 20) and Thrissur districts (AEU 10). A total of 153 trees were selected for the study. Morphological and biochemical characters, abiotic stress (sun burn) susceptibility and incidence of pests, diseases and physiological disorders were recorded from each tree (accession). Variability was observed in qualitative characters like flower and fruit clustering habit, flowering season, fruit size and fruit skin thickness. Dendrogram based on these qualitative characters by UPGMA method grouped 153 accessions into 6 different clusters at a Euclidean similarity distance measure of 1.5. Clusters I, III and IV together consisted of accessions of Wayanad district (AEU 15 and 20) had small and medium sized fruits with medium fruit skin. Cluster I had accessions possessing a combination of flower/fruit clusters which have 1, 2 and 3 flowers/ fruits per cluster. Accessions which flower either during February to April period or April to May period were seen in this cluster. Accessions in cluster III had a combination of flower/fruit clusters posessing either 1 or 2 flowers/fruits per cluster. Flowering was from April to May and May to June. Cluster IV consisted of accessions which had one flower and fruit per flower/fruit cluster. Flowering seasons were same as that of cluster III. Cluster II, V and VI consisted of accessions from Thrissur (AEU 10) only and these accessions had small sized fruits with thin fruit skin. Accessions of cluster II had a combination of flower/fruit cluster with 1 or 2 flowers/fruits per cluster. Flowering season of this cluster was from February to April. Accessions of cluster V had flower/fruit 177 clusters which were similar to that of cluster II. Flowering season of this cluster was from March to April. Cluster VI consisted of two types of accessions; those which produce flower/fruit clusters of single flower/fruit only and those which produce a combination of flower/ fruit clusters of either 1, 2 or 3 flowers/fruits. The flowering season was the same as that of cluster V. Dendrogram based on twenty six quantitative characters, formed using UPGMA method, grouped the accessions into 8 different clusters at a Euclidean similarity distance measure of 30. Principal component analysis (PCA) based on tree and leaf characters revealed that PC1, PC2 and PC3 together contributed 70.95% of variance and had correlation with traits such as age, tree height and leaf petiole width. The loading plot revealed that tree age and tree height; leaf blade length and leaf blade width were the variables having strong positive correlation. PCA bi-plot indicated that Acc.013 to Acc.020, and Acc.077 to Acc 082 were highly diverse from other accessions and the characters contributing to their variance were mainly age of the tree and tree height. PCA based on inflorescence and fruit characters revealed that first six principal components accounted for 67.99% of the total variance among the accessions. Characters contributed mainly to the variance were number of aborted seeds, TSS/acidity ratio, number of mature seeds and acidity. Loading plot showed a strong positive correlation between fruit length and fruit diameter. A strong negative correlation was observed between four pairs of characters. They are number of matured seeds and number of aborted seeds, TSS-acidity ratio and acidity, fruit length and edible portion and fruit diameter and edible portion. PCA bi-plot showed that 30 accessions of Thrissur district i.e., from Acc.124 to Acc.153 were diverse from other accessions and maximum contribution to their variance was from characters like number of aborted seeds or matured seeds and TSS/acidity ratio. The above results indicated that considerable variability exists in qualitative and quantitative characters of mangosteen. Clustering of 62 identified elite clones based on fruit characters like fruit size, edible portion, TSS and acidity using PCA score plot gave 12 different clusters. 9 superior clones (Acc.004, Acc.042, Acc.057, Acc.104, Acc.005, 178 Acc.017, Acc.048, Acc. 121 and Acc.037.) were identified based on economical characters like fruit weight and edible portion. Seven accessions among the identified superior clones were located at RARS Ambalavayal (AEU 20) and two accessions were located at the farmer’s field in Meppadi (AEU 15) of Wayanad district. In future, these nine superior clones could be used for the multiplication of elite clones as well as for creating a germplasm of superior clones. Also, the accessions identified with variations should be subjected for molecular characterization for checking whether variability exists in genetic level. Mangosteen accessions under this study were not susceptible to sun burn. Mild incidence of minor pests and diseases like thrips, mealy bugs, algal spot and anthracnose were observed and were managed at the field itself. Physiological disorders found in mangosteen accessions were gamboge and translucent flesh disorder (TFD).Item Standardization of growth promoters for mangosteen (Garcinia mangostana L.) seedlings(Department of Fruit Science, College of Horticulture, Vellanikkara, 2019) Athira, A S; Sreelatha, UMangosteen (Garcinia mangostana L.) is a promising fruit crop for Kerala due to high price and consumer demand. Slow growth of the seedlings and prolonged pre bearing period are the major factors limiting large scale cultivation of mangosteen. In this context, the present study entitled ‟Standardization of growth promoters for mangosteen (Garcinia mangostana L.) seedlings” was carried out in the Department of Fruit Science, College of Horticulture, Vellanikkara during 2018 to 2019. The main objective of the study was to identify the ideal combination of plant growth promoters for enhancing the growth of mangosteen seedlings. The experiment was laid out in CRD with seventeen treatments replicated thrice. In each replication ten plants were maintained per treatment. Six month old seedlings planted in eight inch pots containing a medium composed of soil + sand + vermicompost in 2:1:1 ratio. Foliar application of NPK mixture (3:1:1) at 0.5 % and 1 % and growth promoters such as GA3 (300 ppm), thiamine (100 ppm), ascorbic acid (100 ppm) were given at monthly intervals during the entire study period (April 2018 to April 2019). Observations on growth characters, root characters, physiological parameters were recorded periodically at different stages of the study. Growth characters such as plant height, plant spread, number of leaves, length and breadth of leaves, total leaf area and internodal length, number of branches were recorded at quarterly intervals upto twelve months after planting. Significant difference was observed among the treatments with respect to plant height and taller seedlings (33.32 cm) with the longest internode (9.44 cm) were observed in T6 (NPK (3:1:1) 0. 5 % + GA3 300 ppm + ascorbic acid 100 ppm. Better plant spread (34.27 cm) was observed in seedlings sprayed with NPK (3:1:1) 0. 5 % (T1). Application of plant growth promoters had no effect on number of leaves produced by mangosteen seedlings. Control plants recorded the highest number of leaves (15.11), which was statistically on par with NPK (3:1:1) 0. 5 % (T1). Leaf length was found to be superior in T1 (NPK (3:1:1) 0. 5 %) at twelve months after planting. However, breadth and total leaf area and Leaf Area Index (LAI) were not influenced by foliar application of nutrients and growth promoters. In general, there was a reduction in all leaf parameters such as number of leaves, leaf length, breadth, total leaf area and LAI in treatments involving GA3. Application of growth promoters could not induce branching in mangosteen seedlings during the period of study. Total number of roots (85.67) was the highest in T1 (NPK (3:1:1) 0. 5 %). Length of the longest root did not show any significant difference among the treatments. However, root spread differed significantly. NPK (3:1:1) 0. 5 % (T1) and NPK (3:1:1) 0. 5 % + thiamine 100 ppm (T3) were the two superior treatments with respect to root spread. Treatments involving GA3 alone and in combination with other growth promoters had an inhibitory effect on root growth and development. Shoot: root ratio was found to be higher (4.64) in T6 (NPK (3:1:1) 0. 5 % + GA3 300 ppm + ascorbic acid 100 ppm) which was on par with control plants. Root hairs were absent in the plants even after twelve months of planting. Highest fresh weight (24.48 g/plant) and dry weight (9.83 g/plant) were noticed in T1 (NPK (3:1:1) 0. 5 %). Plants were analysed for major nutrients (N, P and K) twelve months after planting. Nitrogen, phosphorus and potassium content in the seedlings ranged from 1.4 % - 2.17 %, 0.03 % - 0.10 % and 1.01 % - 1.65 % respectively. Highest nitrogen uptake (190.10 mg/plant) was found in seedlings applied with NPK (3:1:1) 0. 5 % (T1). Higher uptake of phosphorus (5.01 mg/plant) and potassium (120.23 mg/plant) was recorded in T4 (NPK (3:1:1) 0. 5 % + ascorbic acid 100 ppm). The study clearly indicated that foliar application of NPK (3:1:1) 0.5 % (T1) at monthly intervals can be recommended for enhancing the growth of mangosteen seedlings, as superior growth parameters were observed in this treatment. No significant increase in seedling growth was noticed with the foliar spray of NPK 1%.