1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Induction of off-season flowering in Jasmine (Jasminum sambac L.)(Department of Floriculture and Landscape Architecture, College of Agriculture, Vellanikkara, 2021) Sandra Santhosh; Anupama, T VJasminum sambac L. is an important commercial loose flower crop cultivated for fresh flowers and for concrete extraction. Due to seasonal flowering nature of jasmine glut during the peak season and scarcity of flowers during off-season is usually observed, which creates fluctuations in the price of the crop. So regulation of flower production according to market needs is very essential in jasmine. It is in this respect that the possibility of using the combination of pruning with plant growth regulators for regulation of flowering in jasmine assumes significance. The study entitled “Induction of off-season flowering in jasmine (Jasminum sambac L.)” was conducted at the Department of Floriculture and Landscape Architecture at the College of Agriculture, Vellanikkara during 2020-21. The objective of the study was to evaluate the effects of growth regulators and pruning on induction of off-season flowering in jasmine (Jasminum sambac L.). The experiment was laid out in RBD (with two factors) in two replications. Pruning is done during three different time of the year viz. during last week of September (P1), last week of October (P2) and last week of November (P3); along with the applications of growth regulators in two levels viz. cycocel (1000 ppm, 1500 ppm), paclobutrazol (200 ppm, 300 ppm), mepiquat chloride (150 ppm, 300 ppm) and GA3 (100 ppm, 150 ppm). Growth parameters such as plant height, plant spread, number of primary branches and number of secondary branches, physiological characters such as specific leaf area, chlorophyll a, chlorophyll b and total chlorophyll content of leaves; flowering and yield parameters like number of flowers buds per cyme, number of cymes per plant, number of flower buds per plant, weight of hundred flower buds, flower yield per plant, length of flower bud, width of flower bud, corolla tube length, corolla tube girth, flower yield per plant during offseason and peak season were observed. Pruning have a significant influence on growth and flowering of jasmine. There was a significant variation with respect to vegetative parameters viz. plant height and plant spread. Pruning during last week of September (P1) was superior in terms of vegetative parameters such as plant height and plant spread throughout the period of study. During June 21, plants pruned during last week of October (P2) were found to be on par with plants pruned during last week of September (P1) in terms of plant height. Influence of pruning on plant spread was only significant during the months of February and March, plants pruned during last week of September (P1) were found to be on par with plants pruned during last week of October (P2). There was no significant influence noticed on physiological parameters when pruning was done at three different time periods. Days to first flower bud initiation was found to be less in plants (17.96) pruned during last week of November (P3). The number of buds per plant was significantly higher in plants pruned during last week of November (P3) during February, March and April months of observation (226.92, 297.67 and 260.31 respectively). The number of buds per plant was found to be on par in plants pruned during last week of September (P1) and plants pruned during last week of November (P3) during the month of February. Plants pruned during last week of September (P1) and plants pruned during last week of November (P3) were on par in terms of flower yield during the month of January (42.79 g and 48.93 g respectively); plants pruned during last week of November (P3) was superior in the months of March and April. During offseason significant yield was found in plants pruned during last week of September (P1) whereas during peak season pruning during last week of November (P3) gave superior results (328.01 g and 116. 13 g respectively). Influence of growth regulators was studied and found significant effect with respect to plant height and number of secondary branches. The treatments G1 (cycocel 1000 ppm), G3 (paclobutrazol 200 ppm), G4 (paclobutrazol 300 ppm), G7 (GA3 100 ppm), G8 (GA3 150 ppm) and G9 (untreated plants) were found to be on par in terms of this parameter. Specific leaf area was significantly higher in untreated plants (G9) (198.86 cm2 / g) whereas chlorophyll content was significant among the treatments G3 (paclobutrazol 200 ppm) and G4 (paclobutrazol 300 ppm)(1.285 mg/ g and 1.273 mg/ g). Days to bud initiation was significantly varied and G1 (cycocel 1000 ppm) and plants treated with G4 (paclobutrazol 300 ppm) were on par (11.01 and 9.01 days respectively). Plants treated with G1 (cycocel 1000 ppm) and G3 (paclobutrazol 200 ppm) were found to be significantly superior in terms of number of cymes per plant (78.79 and 76.30 respectively) and number of buds per plant (324.77 and 283.34 respectively). Weight of 100 flowers was significantly higher in plants treated with G7 (GA3 100 ppm) in January (26.26 g), February (26.16 g) and March (26.33 g) and G8 (GA3 150 ppm) in January (26.38 g), March (26.33 g) and April (26.72 g). In terms of corolla tube length treatment with G1 (cycocel 1000 ppm), G2 (cycocel 1500 ppm), G3 (paclobutrazol 200 ppm), and G8 (GA3 150 ppm) had a positive influence and were on par. Even though no significance was noticed in other quality parameters the application of growth retardants had a positive influence on quality parameters compared to control. In relation to effect of growth regulators on yield parameters, significant effect was noticed for total flower yield, yield during offseason and yield during peak season. G1 (cycocel at 1000 ppm) (56. 55, 59.54, 53.5 and 55.35 g), G3 (paclobutrazol at 200 ppm) (42.13, 48.31, 45.41 and 53.01 g) and G7 (GA3 at 100 ppm) (41.103, 46.5, 51. 66 and 47.3 g) were on par from January to April in terms of total yield per plant. During offseason G1 (cycocel 1000 ppm), G3 (paclobutrazol 200 ppm) and G7 (GA3 100 ppm) gave the superior result (335.42, 320.43 and 292.07 g respectively) whereas during peak season in G1 (cycocel 1000 ppm), G3 (paclobutrazol 200 ppm) and G4 (paclobutrazol 300 ppm) (108.85, 98.41 and 98.96 respectively) were found to exhibit significant yield. Considering the interaction effect of time of pruning and application of growth regulators, parameters like days to bud initiation, number of cymes per plant, number of buds per plant, corolla tube length, total flower yield per plant and flower yield during offseason and peak season showed a significant influence. Treatments P1 x G3 (pruning during last week of September + drenching of paclobutrazol at 200 ppm), P1 x G4 (Pruning during last week of September + drenching of paclobutrazol 300 ppm), P2 x G1 (pruning during last week of October + spraying of cycocel at 1000 ppm), P2 x G2 (Pruning during last week of October + cycocel at 1500 ppm), P2 x G3 (pruning during last week of October + paclobutrazol 200 ppm), P2 x G4 (Pruning during last week of October + paclobutrazol at 300 ppm), P3 x G3 (Pruning during last week of November + paclobutrazol 200 ppm) and P3 x G4 (Pruning during last week of November + paclobutrazol at 300 ppm) were found to be on par (8.66, 11.38, 13.5, 12.16, 8.33, 10.16, 10.16 and 11.5 days respectively) in terms of number of days taken for flower bud initiation. Interaction effect on total flower yield showed that P1 x G1 (pruning during the last week of September + cycocel at 1000 ppm) (77.66 g), P1 x G3 (pruning during the last week of September + paclobutrazol at 200 ppm) (61.95 g), P3 x G7 (pruning during the last week of November + GA3 at 100 ppm) (74.29 g) and P3 x G8 (pruning during the last week of November + GA3 at 150 ppm) (82.50 g) gave the significant result. In terms of yield during offseason interaction effect of P1 x G1 (pruning during the last week of September + cycocel at 1000 ppm) gave a higher yield (572. 57 g) when compared with other treatment combinations. P3 x G8 (pruning during the last week of November + GA3 at 100 ppm) (162.57 g) and P3 x G7 (pruning during the last week of November + GA3 at 150 ppm) (160. 54 g) were found to be on par during peak season. Considering the overall effect in induction of offseason flowering in jasmine, combination of pruning during last week of September along with the application of cycocel (1000 ppm) or paclobutrazol (200 ppm) gave the best result.Item Standardization of growing medium and growth retardants for compact growth of potted African marigold(Department of Floriculture and Landscape Architecture, College of Agriculture, Vellanikkara, 2021) Niranjana Gopal; Mini SankarThe study entitled “ Standardization of growing medium and growth retardants for compact growth of potted African marigold” was carried out in the Department of Floriculture and Landscape Architecture, College of Agriculture, Vellanikkara during 2020-2021. The objective of the study was standardization of growing medium and growth retardants for regulating growth of potted African marigold for display purpose. The experiment consisted of five different media viz; cocopeat (60%) + vermicompost (20%) + vermiculite (10 %) + rice husk (10%) [M1], cocopeat (60%) + FYM (20%) + vermiculite (10%) + rice husk (10%) [M2], cocopeat (40%) + soil (20%) + vermicompost (20%) + vermiculite (10%) + rice husk(10%) [M3], cocopeat (40%) + soil (20%) + FYM (20%) + vermiculite (10%) + rice husk (10%) [M4] and soil: FYM: sand (1:1:1) [M5] and two growth retardants in three different levels viz; cycocel [750 ppm (GR1), 1000 ppm (GR2) and 1500 ppm (GR3)] and paclobutrazol [30 ppm (GR4), 60 ppm (GR5) and 90 ppm (GR6)] along with a control group of each media without application of growth retardants. Four week old seedling of marigold variety ‘Double Orange’ was used for the study. Observations on vegetative characters, Floral characters as well as the nutrient status of growing media were recorded. With regard to vegetative characters, growing media, growth retardants and interaction between growing media and growth retardants had significant influence. Shortest plants were observed in M1 [cocopeat (60%) + vermicompost (20%) + vermiculite (10 %) + rice husk (10%)] and among the growth retardants, paclobutrazol at 90 ppm [GR6] was found to produce short plants. The same treatment were also found superior with respect to plant spread, number of branches and number of leaves. Regarding interaction effect an improvement in all vegetative parameters was observed in M4 [cocopeat (40%) + soil (20%) +FYM (20%) + vermiculite (10%) + rice husk (10%)] x GR6 [paclobutrazol 90 ppm]. Significant effects of growing media could be observed in floral characters and M4 was found superior with respect to floral characters Viz; number of flowers per plant (10.14), flower diameter (4.61 cm)and field life of individual flowers (9.21 days). M2 was found superior in terms of other floral ABSTRACT characters viz; days taken for first flower bud emergence and days taken from flower bud initiation to flower opening. With respect to the influence of growth retardants on floral characters, a greater number of flowers per plant (9.50), flower diameter (4.22), flowering duration (96 days) and field life of individual flowers were observed by the application of paclobutrazol at 90 ppm. Growing medium and growth retardant interaction had significant influence on floral characters. Lowest days for first flower bud emergence and from flower bud initiation to flower opening were observed in M2 [cocopeat (60%) + FYM (20%) + vermiculite (10%) + rice husk (10%)] x GR1 [cycocel 750 ppm]. Number of flowers per plant was highest in M4 x GR6, M5 x GR6 and M4 x GR5 [paclobutrazol 60 ppm]. Treatment combination M4 x GR6, M5 x GR6 and M4 x GR4 [paclobutrazol 30 ppm] were superior with respect to flower diameter and field life of individual flowers. Analysis of growing media before and after the experiment for differentphysio- chemical properties revealed that M1 had the lowest bulk density (g/cm3 ) highest porosity (%) and water holding capacity (%).The chemical properties pH and EC of all the media were found in the favourable range [pH - 5.8- 6.2; EC<1.5dS/m] both before and after the experiment. Available N, P, K before and after the experiment was found highest in M4 .Plant nutrient content (NPK), Total chlorophyll content and uptake of nitrogen and potassium by plants were also found higher in M4. From the overall performance, it could be noted that the vegetative parameters viz; plant spread, number of branches and number of leaves as well as floral parameters such as number of flowers, size of flowers and field life of individual flowers were in desirable range in treatment combination M4 x GR6. Hence the medium M4 [cocopeat (40%) + soil (20%) + FYM (20%) + vermiculite (10%) + rice husk (10%)] along with application of paclobutrazol 90 ppm [GR6] 20 and 35 days after pinching can be recommended for compact growth of potted Africanmarigold