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Subject: Floriculture and Landscaping × Author: Ranjit Singh × End date: 2018 × Start date: 2018 × Type: Thesis × Thesis Type: Ph.D ×
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    Flowering response of chrysanthemum (Chrysanthemum morifolium Ramat.) genotypes to different photoperiods and quality of light
    (Punjab Agricultural University, Ludhiana, 2018) Ranjit Singh; Madhu Bala
    The present investigations entitled “Flowering response of chrysanthemum (Chrysanthemum morifolium Ramat.) genotypes to different photoperiods and quality of light” were carried out at the Research Farm, Department of Floriculture and Landscaping, Punjab Agricultural University, Ludhiana, during 2015-18. The experiments were conducted to study the response of standard and spray genotypes to artificial short day conditions. The plants were raised through the rooting of terminal cuttings during February-March and the plants were given short day treatment as night extension using black polythene (100 micron) sheet from civil twilight in the morning to 9 O’clock. The maximum plant height (85.33 cm and 86.00 cm) and plant spread (19.33 cm and 18.67 cm) was exhibited by Boris Becker while number of branches were recorded maximum (5.00 and 5.00) in Punjab Shyamli for both the years. The leaf area index, leaf weight ratio and number of stomata per unit area were not affected significantly. Days to flower bud appearance were recorded minimum (108 and 107.65) in two genotypes viz. Yellow Delight followed by Banglori Local (117 and 110), accordingly early flowering was observed in these genotypes, showing good tolerance towards heat delay. Similar trend was recorded in standard types but none of the genotypes was able to flower early in response to artificial short days. In second experiment different sources of light viz. incandescent bulbs, CFL and LED as night break were used, from 15th August to 31st October, from 10.00 pm to 12.00 midnight to provide long days. Plant spread (25.73 cm and 26.65 cm), days to flower bud appearance (148.34 and 149.25), days to flowering (178.10 and 180.10), flower size (6.85 cm and 7.13 cm) and vase life (12.27 days and 12.55 days) were recorded maximum with LED sources of light as compared to incandescent and CFL. Similarly another experiment was conducted by providing long days with the help of LED lights of red, blue and green colour to investigate the effect of colours of light for night break treatment. The genotypes under red lights exhibited maximum (66.83 cm) plant height, plant spread (18.02 cm), days to bud appearance (142.93 days), days to flowering (170.08 days), flower size (6.69 cm), duration of flowering (31.95 days) whereas stem diameter and vase life was recorded maximum (5.80 mm and 11.27 days, respectively) under blue light. Green lights have resulted in increased content of carotenoids over red and blue LED lights. Similar trend was observed in genotype of standard group. It is thus concluded that the genotypes viz. Yellow Delight and Banglori Local among spray type were suitable for year round flower production as they have exhibited tolerance against heat delay. Among the different sources and colours of light, light emitting diodes (LED) with red colour light were found suitable for effective photoperiodic control for growth and flowering in Chrysanthemum.