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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem Open Access Standardization of production technology for African marigold(Tagetes erecta L.)(Department of Floriculture and Landscaping, College of Horticulture, Vellanikkara, 2020) Jeevan, U; KAU; Sreelatha, UMarigold (Tagetes spp.), one of the commercially grown flower crops in India, is of multipurpose uses in floriculture, pharmaceutical, cosmetic and dye industries. The present investigation entitled “Standardization of production technology for African marigold (Tagetes erecta L.) was undertaken in the Department of Floriculture and Landscaping, during the year 2018-2020. The research programme consisted of five experiments. The first experiment was ‘Performance evaluation of African marigold and evaluation of other Tagetes spp. against bacterial wilt’. Thirty two marigold genotypes from three different species of Tagetes viz., T. erecta, T. patula and T. tenuifolia were evaluated in a wilt sick plot, for assessing bacterial wilt incidence during rainy (June-September) and winter (October–January) seasons. Genotypes of T. erecta M-1 and M-2 did not show bacterial wilt incidence during both seasons and these genotypes were categorised as completely resistant to bacterial wilt. Wilt incidence in other genotypes ranged from 4.16 per cent to 87.50 per cent during rainy season while during winter, it ranged from 27.7 per cent to 100.00 per cent. Compared to rainy season (43.00%), bacterial wilt incidence was more severe during winter season (70.00%). Days to wilt was also very early during winter (26.00 days) than rainy season (71.00 days). Significant negative correlation was observed between flavonoid content (leaves and petals) and bacterial wilt incidence. The causal organism of marigold wilt was characterized and identified as Enterobacter cloacae and this is first report of the bacterium in marigold. The 16SrDNA sequence data were deposited in NCBI (MT649902 and MT649903). From the performance evaluation, it could be observed that the genotypes viz., Bhagwati, Royal Orange, Maria-91, Rupa and P-4 were superior with respect to morphological characters. These F1 hybrids also recorded greater flower weight as well as petal weight. Genotypes P-4, Maria 91 and Bhagwati recorded significantly greater number of flowers per plant (59.10, 52.07, 51.23, respectively), and yield per plant (476.80g, 355.17g, 319.73g respectively). The highest carotenoid content was recorded in the genotype Bhagwati (0.105 mg/g). In the second experiment, twelve genotypes which were categorized as resistant as well as moderately resistant during field evaluation, were subjected to artificial inoculation studies. The genotypes M-1 and M-2 were found to be completely wilt resistant in artificial screening. Among other genotypes, Bhagwati showed a lower bacterial wilt incidence of 26.00 per cent. The third experiment was conducted with the objective to evaluate rootstocks for T. erecta. Two resistant genotypes viz., M-1 and M-2 were used as rootstocks for grafting nine susceptible genotypes which consisted five F1 hybrids (Bhagwati, Maria 91, Sakuara 031, Suvarna Orange and Suvarna Yellow) and four varieties (Pusa Narangi Gainda, Pusa Basanti Gainda, Double orange and Double Yellow). F1 hybrids recorded better graft survival compared to varieties. Significantly greater graft survival was recorded in Bhagwati and Maria 91, grafted on M-1 rootstock (60% and 54%, respectively) and M-2 rootstock (54% and 50%, respectively). The fourth experiment was conducted during rainy, winter and summer seasons under precision farming system using two selected genotypes viz., Bhagwati and M-1. Irrigation was given @ 75 and 100 per cent Epan and fertigation was given at 75, 100 and 125 per cent of IIHR recommendation (90:90:75 kg/ha) for marigold. During rainy season, fertigation @ 75 per cent RDF (F1) recorded a yield of 35.00 t/ha for Bhagwati and 13.00 t/ha for M-1 which were double the yield in the control treatments of respective genotypes. During winter and summer seasons, irrigation @ 100 per cent Epan along with fertigation @ 125 per cent RDF (I2F3) recorded the greatest yield of 12.50 and 10.00 t/ha respectively in Bhagwati. WUE was the highest in the treatment I2F3 for Bhagwati and M-1 during winter (10.92 kg/ha mm-1, 10.11 kg/ha mm-1) and summer (6.79 kg/ha mm-1, 7.02 kg/ha mm-1) seasons. The fifth experiment was conducted to study the effect of growth regulators on plant growth and yield by using F1 hybrid Bhagwati during rainy and winter season. Spraying growth retardant CCC @ 1000 mg/L during rainy season at 30 and 45 days after transplanting (DAT), was proved to be the best treatment for reducing the plant height (24%) and improvement of yield (14%). CCC @ 1000 mg/L delayed flowering by 12 days compared to control. During winter, spraying growth promoter GA3 @ 300 mg/ L (30 and 45 DAT) was the best for enhancing vegetative growth and yield (28.00%) over control. The study could identify a new wilt causal organism of bacterial wilt in marigold and it was identified as Enterobacter cloacae. Among the thirty two genotypes evaluated, two genotypes viz., M-1 and M-2 were identified as bacterial wilt resistant types. With regard to Tagetes erecta, among the F1 hybrids, Bhagwati, Maria- 91, P-4, Sakura 031 showed better performance in terms of flower yield whereas among the varieties, Double Orange, and Arka Agni and Arka Bangara-2 showed better performance with respect to floral parameters and flower yield. F1 hybrids with good yield but highly susceptible to bacterial wilt can be grafted on resistant rootstock genotypes. F1 hybrids showed better graft survival compared to varieties. Greater graft survival (60%) was recorded for Bhagwati on M-1 rootstock. During rainy season 75 % RDF (90:90:75) was the best with respect to the yield and quality parameters. During winter and summer I2F3 (100% Epan along with 125% RDF) was performing best. Hybrid Bhagwati was performing well during all the seasons studied, with the highest B:C ratio. Genotype M-1 can be suggested as an alternate variety during winter season. During rainy season spraying CCC @ 1000 mg/L (30 and 45 DAT) was found the best treatment for reduction in plant height (24%) and increased yield (14%) over control. CCC @ 1000 mg/L can also be used for delaying flowering in marigold. During winter, spraying GA3 @ 300 mg/L or 200 mg/L (30 and 45 DAT) enhanced the plant height (15%, 11% respectively) and yield per plant (28%, 22% respectively) over control.ThesisItem Open Access Ecophysiology and Screening for climate change resilience in Mango (Mangifera indica L.) Genotypes(Department of Pomology and Floriculture College of Agriculture,Vellayani, 2019) Aswini, A; KAU; Jyothi BhaskarThe study on “Ecophysiology and screening for climate change resilience in mango (Mangifera indica L.) genotypes” was conducted with the objective of getting basic information on eco physiological responses among selected genotypes of mango on flushing, flowering and fruit development with a view to identify climate resilient genotypes that are suitable for future climate change scenario in Kerala. The study comprised of three experiments viz., evaluation of mango genotypes under normal planting system, evaluation of selected mango genotypes in high density planting system and development of a crop weather model for mango and screening of genotypes for climate resilience with developed crop weather models. Experiment on evaluation of mango genotypes under normal planting system was conducted with trees of same age group (23 years). Wide variation was observed among the morphological characters, physiological characters, biochemical characters and quality attributes of different mango genotypes. From the observations on tree characters, the plant height varied from 9.78 m (H 151) to 12.49 m (Chandrakaran), the trunk circumference ranged from 91.63 cm (Muvandan) to 196.53 cm (Swarnarekha), and the crown diameter varied from 7.07 m (H 151) to 13.46 m (Mulgoa). The qualitative data on morphological characters viz., tree, leaf, inflorescence, fruit, stone and seed characters were grouped into clusters based on the IBPGRI descriptor. The observation on leaf characters revealed that the leaf blade length varied from 19.78 cm (Chandrakaran) to 29.32 cm (Amrapali), leaf blade width ranged from 4.77 cm (Kalepady) to 8.12 cm (Vellaikolumban), and the petiole length varied from 1.56 cm (H 45) to 3.70 cm (Amrapali). Based on the observations on inflorescence character the inflorescence length varied from 12.58 cm (Dashehari) to 34.42 cm (Bennet Alphonso), the inflorescence width ranged from 9.32 cm to 3.40 cm (Vellaikolumban), the hermaphrodite flowers in the inflorescence varied from 14.00% (Mulgoa) to 67.83% (Neelum), and the number of stamens per flower ranged from 4 to 5. From the observations on fruit characters the fruit length varied from 7.60 cm (Chandrakaran) to 20.08 cm (Mulgoa), fruit diameter ranged from 17.05 cm (h 151) to 32.50 cm (Arka Aruna), the fruit weight ranged from 123.10 g (Chandrakaran) to 738.97 g (Mulgoa), the fruit yield varied from 9.75 kg/tree (Arka Aruna) to 52.13 kg/tree (Muvandan) and the shelf life ranged from 3.83 days (PKM 2) to 7 days (H 151). From the observations on stone characters stone length, varied from 5.60 cm (Muvandan and Neelum) to 14.05 cm (Mulgoa), stone width ranged from 3.17 cm (Muvandan) to 12.07 cm (H 45 ), the stone thickness varied from 1.20 cm (Muvandan) to 3.15 cm (Neelgoa) and the stone weight ranged from 15.93 g (Bennet Alphonso) to 47.13 g (Mulgoa). Based on the seed characters the seed length varied from 4.28 cm (Bennet Alphonso) to 11.22 cm (Mulgoa), the seed width ranged from 2.25 cm (Sindhu) to 8.88 cm (Banganapalli) and the seed weight ranged from 8.58 g (Vellaikoamban) to 28.98 g (Mulgoa). The results from the analysis of quality attributes of different genotypes indicated that the acidity ranged from 0.02 % (Kalepady and H 151) to 0.12 % (Himayuddin), the ascorbic acid ranged from 12.17 mg 100g-1 (Arka Aruna) to 72.49 mg 100g-1 (Muvandan), carotenoids varied from 0.16 mg 100g-1 (Neelum) to 8.47 mg 100g-1 (Alphonso), ß carotene ranged from 9.75 mg 100g-1 (Mulgoa) to 45.06 mg 100g-1 (Dashehari), the total sugar varied from 12.55 % (Tholikkaipan) to 27.81 % (Swarnarekha), the reducing sugar ranged from 5.37 % (Swarnarekha) to 10.38 % (Tholikkaipan), the crude fibre varied from 2.67 % (Alphonso) to 16.50 % (Arka Aruna) and the TSS ranged from 16.16 oBrix (Kalepady) to 27.68 oBrix (Himayyudin). The results from sensory evaluation indicated that Mallika secured the highest rank for appearance, flavour, sweetness and texture, whereas Ratna secured the highest rank for clour and taste. The studies on pollen characters showed that the pollen length varied from 26.40 μm (Neelgoa) to 45.72 μm (Himayuddin), the pollen breadth ranged from 22.92 μm (Muvandan) to 38.34 μm (Arka Aruna), the pollen fertility ranged from 82.70 μm (Mulgoa) to 93.60 μm (Tholikkaipan) and the pollen production varied from 299.00 (H 151) to 541.83 (Prior). The pollen shapes of different mango genotypes observared were oblong, oval and round. The pollen storage was standardized using the pollen grains of Mallika and it was found that keeping under refrigerated conditions at 4OC was ambient. In vitro pollen germination were tried by hanging drop technique in different concentrations of sucrose solution with 1% agar and 0.001% boric acid but no germination was observed. The studies on physiological characters of different mango genotypes revealed that the relative water content varied from 19.00% (Ratna) to 35.82% (Neelum), radiation interception varied from 0.68 μ mol m-2 s-2 (Tholikkaipan) to 0.92 m-2 s-2 (Mulgoa), stomatal index varied from 15.59 (Prior) to 22.44 (Mallika), the stomatal frequency ranged from 65.22 to 88.78 (Banganappalli), the variation on stomatal conductance among the mango genotypes was found to be non significant, the stomatal resistance ranged from 5.33 μ mol m-2 s-2 (Dashehari) to 37.92 μ mol m-2 s-2 (Swarnarekha), the photosynthetic rate varied from 7.57 μ mol m-2 s-2 (H 151) to 17.91 μ mol m-2 s-2 (Tholikkaipan), the transpiration rate varied from 1.41 μ mol m-2 s-2 (Vellaikolumban) to 4.15 μ mol m-2 s-2 ( Dashehari), the leaf area index varied from 0.69 ( Dashehari) to 2.07 (Muvandan), and atmospheric pollution tolerance index ranged from 42.07 (Muvandan) to 68.53 (Mallika). The biochemical studies revealed that total phenol content varied from 4.54 mg g-1 to 19.07 mg g-1 (Ratna), soluble protein varied from 8.60 mg g-1 (Prior ) to 20.04 mg g-1 (Muvandan), the ascorbic acid content varied from 63.29 mg g-1 (Swarnarekha) to 97.21 mg g-1 (Ratna), the leaf pH ranged from 5.14 (Muvandan) to 6.45 (PKM 2), the chlorophyll a content varied from 0.82 mg g-1 (Chandrakaran) to 1.31 mg g-1 (Sindhu), the chlrophyll b content ranged from 0.13 mg g-1 (Banganappalli) to 0.26 mg g-1 (Tholikaippan), and the total chlorophyll ranged from 0.99 mg g-1 (Chandrakaran) to 1.48 mg g-1 (H 45). For the study on evaluation of mango genotypes under high density planting the trees of same age group (5 years) were selected. The observation on tree characters indicated that the trunk circumference ranged from 20.51 cm (Prior) to 31.29 cm (Chandrakaran), crown diameter ranged from 2.39 m (Ratna) to 3.09 m (Vellaikolumban). The qualitative data on morphological characters viz., tree, leaf, inflorescence, fruit, stone and seed characters were grouped into clusters based on the IBPGRI descriptor. The observation on leaf characters revealed that the leaf blade length varied from 19.17 cm (Muvandan) to 25.40 cm (Ratna), leaf blade width ranged from 4.84 cm (Muvandan) to 7.68 cm (Vellaikolumban) and leaf petiole length varied from 2.29 cm (Chandrakaran) to 4.18 cm (Vellaikolumban). Based on the inflorescence characters, the inflorescence length varied from 22.14 cm (Prior) to 36.47 cm (Vellaikolumban), the hermaphrodite flowers ranged from 33.40% (Muvandan) to 85.80% (Chandrakaran) and the number of stamens varied from 3 to 4. The observation on fruit characters revealed that the fruit length varied from 7.49 cm (Chandrakaran) to 18.71 cm (Mallika), the fruit diameter ranged from 13.18 cm (Chandrakaran) to 25.25 cm (Mallika), the fruit weight ranged from 8.93 g (Muvandan) to 24.69 g (Mallika), the yield per tree ranged from 8.93 kg/tree (Muvandan) to 24.69 kg/tree (Mallika), and the shelf life of fruits varied from 4 to 6 days. The observations on stone and seed characters revealed that chandrakaran recorded the lowest stone length (5.58 cm), stone width (3.36 cm), stone thickness (1.23 cm), stone weight (17.79 g) and seed length (4.05 cm). The lowest seed width and seed weight was recorded by Prior (3.07cm) and Vellaikolumban (9.44 cm). The highest stone length was recorded by Mallika (11.67 cm), stone width by Ratna (8.67 cm), stone thickness by Vellaikolumban (2.19 cm), stone weight by Mallika (44.33 g) , seed weight by Prior (22.22 g) and seed length and width by Ratna (7.91 cm and 8.47 cm respectively). Based on the analysis on quality attributes on different mango genotyped under high density planting the TSS ranged from 14.78 oBrix (Muvandan), acidity varied from 0.02 % (Mallika) to 0.07 % (Muvandan), ascorbic acid varied from 28.26 mg 100g-1(Vellaikolumban) to 79.68 mg 100g-1 (Chandrakaran), carotenoids ranged from 1.40 mg 100g-1(Vellaikolumban) to 4.80 mg 100g-1(Ratna), and ß carotene ranged from 13.54 mg 100g-1(Vellaikolumban) to 39.93 mg 100g-1(Ratna). The results on sensory evaluation revealed that Ratna recorded the highest rank for colour, flavour, sweetness, texture and taste, whereas Mallika recorded the highest rank for appearance. The pollen studies indicated that the pollen length varied from 24.80 μm (Muvandan) to 44.00 μm (Prior), pollen breadth ranged from 22.62 μm (Muvandan) to 33.35 μm (Chandrakaran), pollen fertility ranged from 59.47% (Prior) to 79.29% (Mallika) and the pollen production ranged from 194.50 (Muvandan) to 306.10 (Vellaikolumban). The studies on physiolological characters showed that the radiation interception ranged from 0.77 μ mol m-2 s-2 (Ratna and Chandrakaran) to 0.61 μ mol m-2 s-2 (Prior), the stomatal index ranged from 17.87 (Mallika) to 21.37 (Ratna), the stomatal frequency varied from 63.73 (Mallika) to 81.40 (Ratna), stomatal conductance ranged from 0.09 μ mol m-2 s-2 (Prior) to 0.19 μ mol m- 2 s-2 (Muvandan), stomatal resistance ranged from 7.31 μ mol m-2 s-2 ( (Muvandan) to 19.79 μ mol m-2 s-2 (Prior), the photosynthetic rate varied from 3.17 μ mol m-2 s-2 (Chandrakaran) to 11.68 μ mol m-2 s-2 (Vellaikolumban), transpiration ranged from 2.44 μ mol m-2 s-2 (Chandrakaran) to 4.19 μ mol m-2 s-2 (Muvandan) and atmospheric pollution tolerance index ranged from 54.42 (Vellaikolumban) to 68.34 (Ratna). The studies on biochemical character revealed that total phenol content varied from 4.81 mg g-1 (Vellaikolumban) to 10.66 mg g-1 (Prior), soluble protein varied from 12.72 mg g-1 (Ratna) to 20.75 mg g-1 (Chandrakaran), ascorbic acid content ranged from 67.74 mg g-1 (Vellaikolumban) to 92.34 mg g-1 (Ratna), leaf pH varied from 5.57 (Ratna) to 6.15 (Muvandan), chlorophyll a content ranged from 1.09 mg g-1 (Muvandan) to 1.29 (Prior), chlorophyll b varied from 0.22 mg g-1 (Muvandan) to 0.29 mg g-1 (Chandrakaran) and total chlorophyll varied from 1.30 mg g-1 (Muvandan) to 1.55 mg g-1 (Prior). Future climate change projection for 2030, 2040 and 2050 based on RCP 4.5 was generated using ECHAM model and the performance of the various genotypes under projected climatic conditions was evaluated using the developed model. Correlation among different meteorological and phenological characters of mango genotypes were done for yield, regression equations were derived and the yield was predicted from the scenario. Three phenophases viz., flower initiation, fruit initiation and fruit maturation were taken for the study. In each phenophase, weather parameter for seven, fifteen and thirty days prior to date of expression were averaged individually for correlation. Sindhu, Vellaikolumban, Prior, Alphonso, Kalepady and Tholikaippan showed an increase in the predicted yield in spite of an increase in temperature in flowering phenophase under normal planting system. The predicted yield increased in spite of a decrease in solar radiation in H 45, Mulgoa and Tholikaippan,. The predicted yield increased in spite of a decrease in rainfall in Dashehari, Neelum and Muvandan. Amrapali, PKM 1, Alphonso, Himayuddin, Swarnarekha and Mulgoa showed an increase in predicted yield in spite of an increase in rainfall. Amrapali, PKM 1, Sindhu, Neelum, Himayyudin, Bennet Alphonso, Kalepady, Muvandan, Tholikaippan, Vellaikolumaban, Banganapalli and Prior, recorded an increase in predicted yield in spite of an increase in temperature in fruit initiation phenophase under normal planting system. The predicted yield increased in spite of a decrease in rainfall in PKM 1, Amrapali, H 151, H 45, Bennet Alphonso, Mulgoa, Tholikkaipan, Chandrakaran and Muvandan. Dashehari showed an increase in predicted yield in spite of an increase in rainfall. H 151, Kalepady and Swarnarekha showed an increase in the predicted yield in spite of an increase in rainfall in fruit maturation phenophase under normal planting system. Based on the performance of genotypes in all three phenophases, H 45 can be recommended for regions with lower rainfall and lower solar radiation among the hybrids under normal planting system, whereas, Amrapali and PKM 1 can be recommended for areas with higher temperature and for both higher and lower rainfall regions. Among the parents of the hybrids, Mulgoa can be recommended for regions with lower solar radiation and for both lower and higher rainfall regions. Among the local types, Tholikaippan can be recommended for the regions with higher temperature, lower rainfall and lower solar radiation. Vellaikolumban, Ratna and Muvandan showed an increase in the predicted yield in spite of an increase in temperature in flowering phenophase under high density planting system. Prior, Chandrakaran, Muvandan, Vellaikolumban, Ratna and Mallika recorded an increase in the predicted yield in spite of an increase in temperature in fruit initiation phenophase under high density planting system. Prior, Chandrakaran, Mallika, Ratna and Muvandan, showed an increase in the yield in spite of an increase in temperature in fruit maturation phenophase under high density planting system, whereas the predicted yield increased in spite of a decrease in rainfall in Mallika, Vellaikolumban and Ratna. Based on the performance of genotypes in all the three phenophases, all studied genotypes can be recommended for higher temperature regions under high density planting system. In conclusion, climate change may have a profound impact on mango genotypes since the flower initiation, fruit initiation and fruit maturation phenophases are strongly influenced by the environment. The projected scenario for 2030, 2040 and 2050 indicate that the temperature will tend to increase and the rainfall will decrease from the present condition leading to altered phenophases which necessitate changes in spectrum and distribution of varieties currently being grown. H 45, PKM 1, Amrapali, Mulgoa and Tholikaippan are the climate resilient genotypes for the normal planting systems and Mallika, Ratna, Muvandan, Vellaikolumban and Prior are the climate resilient genotypes for high density planting systems.ThesisItem Open Access Evaluation of propagation techniques and rootstock studies of mango (Mangifera indica L.)(Department of Pomology and Floriculture College of Agriculture, Vellayani, 2019) Reshma, U R; KAU; Simi, SAn investigation entitled “Evaluation of propagation techniques and rootstock studies of mango (Mangifera indica L.)” was carried out during 2016– 2019 at Department of Pomology and Floriculture, College of Agriculture, Vellayani. The investigation aimed to screen local mango varieties/ collections for polyembryony, to study the pre-sowing treatments, sowing positions and age of stone after extraction from fruit on germination of mango stones, to screen local mango varieties for use as dwarfing rootstocks and to study the effect of two propagation methods in three modified environments on three varieties of scions. Out of twenty local mango varieties collected from different parts of Thiruvananthapuram district of Kerala, seventeen were polyembryonic while three were monoembryonic. The mango var. Kappa Manga (T19) recorded the highest germination per cent (73.33 %), germination index (2.41) and seedling vigour index on growth basis (2795.20). The mean germination time (17.50 days) was the least in Vellari Varikka (T18). Kotookonam Varikka recorded the highest per cent polyembryony (65.13 %) and produced the highest number of plantlets per stone (5.00). Microsatellite analysis of all the plantlets from two varieties viz., Kotookonam Varikka and Kochu Kilichundan that exhibited the highest percentage of polyembryony were done using 20 SSR primers and the products were compared with their respective mother plants. All the seedlings obtained from the respective stones had identical SSR profile to the mother plant, which indicated nucellar origin of seedlings having similar genetic composition to the mother plant. The zygotic seedling might have degenerated at very early stage of growth and the remaining nucellar seedlings were all vigorous. To study the effect of pre-sowing treatments, sowing positions and age of stone after extraction from the fruit on germination of mango stones, an experiment was laid out in completely randomized design with 42 treatment combinations replicated thrice. The treatments comprised two sowing positions viz., flat (S1) and stalk end up (S2), three age of stones after extraction from fruit, viz., freshly extracted (A1), 10 days (A2) and 20 days after extraction (A3) and seven pre-sowing treatments viz., 100 ppm GA3 (T1), 200 ppm GA3 (T2), 1 ppm KNO3 (T3), 2 ppm KNO3 (T4), cow dung slurry(T5), water (T6), control [without treatment (T7)] and their combinations. The variety Kotookonam Varikka was utilized for the study. The stalk end up sowing method and freshly extracted stones proved to be the best with respect to germination and vigour of mango seedlings. The stones treated with 200 ppm GA3 required minimum number of days for initiation of germination (22.62 days), 50 % germination (31.78 days), exhibited the highest germination percentage (62.59 %), rate of germination (0.48), vigour index on growth basis (2310.02) and weight basis (657.09). Treatment with 100 ppm GA3 produced the highest seedling length (35.70 cm) and dry weight (10.39 g) at 4 month after sowing (MAS). Interaction effects also indicated that the freshly extracted stones sown by stalk end up method after treatment with 200 ppm GA3 for 24 hours resulted in significantly the highest germination rate (0.74) and the least number of days for initiation of germination (13.00 days). An attempt was made to identify the local mango varieties for use as dwarfing rootstock based on morphological, physiological and anatomical features. The experiment was laid out in completely randomized design (CRD) with ten genotypes replicated thrice. At 4 MAS, the lowest seedling length (29.48 cm) was noticed in Kochu Kilichundan (T4), followed by Unda Varikka (T10) and the highest seedling length (56.11 cm) was in Kappa Manga (T8). Moreover, the germination percentage of Kochu Kilichundan (46.67 %) was on par with all the varieties except Kappa Manga (71.11 %) along with the lowest vigour index-I and vigour index- II was on par with Unda Varikka. However, the least dry matter of seedling (9.66 g) was recorded in Unda Varikka. At 6 MAS, majority of the morphological features were the highest in Kappa Manga. The highest starch content (8.53 %) was estimated to be in Kasthuri (T2). Kochu Kilichundan and Unda Varikka exhibited dwarfism with less plant height (38.77 cm and 40.20 cm respectively), but the former had the least internodal length (3.16 cm). The highest values for number of leaves (23.20), leaf length (12.59 cm), leaf width (4.07 cm) and average leaf area (22.57 cm2) were recorded in Unda Varikka compared to Kochu Kilichundan. However, the highest number of roots (28.53), root length (35.02 cm), dry weight of root (3.10 g), dry weight of shoot (1.46 g) and stomatal density (51.68) were recorded in Kochu Kilichundan while total leaf area of the two varieties were on par. Moreover, Kochu Kilichundan had the highest phenol content in apical bud (60.57 mg/g) and leaves (29.03 mg/g) and bark percentage of root (23.69 %) and shoot (34.02 %) of all the varieties. Membrane stability index, relative water content, transpiration rate and leaf temperature were non-significant. The anatomical studies revealed the highest phloem-xylem ratio both in stem (0.99) and root (1.35) and the least total conduit area of root (6.38 mm2) in Unda Varikka while the least total conduit area of stem (5.42 mm2) was in Kochu Kilichundan, indicating the dwarfing potential of both Kochu Kilichundan and Unda Varikka. To study the effect of propagation methods and modified environments on different varieties of scion, an experiment was laid out in completely randomized design with eighteen treatment combinations replicated thrice. The treatments comprised two propagation methods viz., epicotyl (P1) and softwood grafting (P2), three modified environments viz., climate controlled [fan and pad (M1)], humid chamber (M2) and natural shade [75 % shade (M3)] and three varieties of scions, Kalapady (V1), Neelum (V2) and Kotookonam Varikka (V3) and their combinations. The grafts produced by epicotyl grafting resulted in significantly higher scion length (15.80 cm), had the least number of days for leaf opening (15.07days) , first (12.19 days) and last sprouting (22.02), higher number of grafts sprouted at weekly intervals, higher initial success percentage (83.21 %), graft establishment percentage (72.22 %), number of leaves per graft (15.40), leaf length (15.27 cm), leaf width (3.36 cm), leaf area (41.69 cm2), number of nodes on scion (21.63), internodal length (5.20 cm), number of growth flushes per graft (1.76), lower number of days taken between grafting to first vegetative flush (26.06 days) as well as to second vegetative flush (44.98 days) and higher final survival of grafts (65.19 %). The micro climate controlled by fan and pad system produced most conducive conditions for vegetative growth of mango grafts. Among the different varieties of scions, Kotookonam Varikka recorded the highest girth of rootstock, girth of scion, length of scion, graft height, spread of plant in N-S direction and E-W direction, number of grafts sprouted at weekly intervals, initial success percentage, percentage of graft establishment, leaf width, number of nodes on scion, internodal length, number of growth flushes per graft and the lowest number of days taken between grafting and second vegetative flush. Kalapady recorded the least number of days for first and last sprouting, leaf opening and for first vegetative flushing. The greatest sprout length, number of leaves, leaf length and leaf area were recorded in Neelum. The scion did not influence the final survival of grafts. The treatment combinations had no influence on root length. Interaction effects also confirmed that epicotyl grafting method with Kotookonam Varikka variety as scion under controlled conditions using fan and pad system resulted in grafts with higher scion length (16.80 cm), sprout length (6.05 cm), more number of growth flushes per graft (2.33) and earlier second vegetative flush (40.87 days). Based on the above findings it could be concluded that the highest percentage of polyembryony was in Kotookonam Varikka and microsatellite analysis revealed the nucellar origin of plantlets and confirmed higher vigour of nucellar seedlings over sexual seedling. Stalk end up sowing of freshly extracted stones treated with 200 ppm GA3 for 24 hours recorded better germination and vigour of mango seedlings. The mango variety Kochu Kilichundan and UndaVarikka were identified as promising rootstocks to impart dwarfness and Kochu Kilichundan was superior in most of the morphological and physiological characters. The epicotyl grafts of Kotookonam Varikka under controlled climate by fan and pad system recorded better graft establishment, survival, vegetative and growth parameters.
