MSc

The studies on ‘Enhancement of spike qualities of Gladiolus (Gladiolus grandiflorus L)” were conducted during 2012-13 in the Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, in two seasons, from May 2012 to October 2012 (first season) and from November 2012 to April 2013 (second season). The objectives were to compare the performance of gladiolus varieties under open and rain shelter conditions and to standardize the post harvest treatments to improve the spike qualities.
The three gladiolus varieties namely Oscar, Summer Sunshine and White Prosperity, were grown as per KAU recommendation, both in open field and rain shelter. Detailed observations were made on growth, flowering and post harvest characters.
The study clearly indicated that growing condition, season and genotype had significant influence on vegetative as well as floral characters of gladiolus. The vegetative characters like plant height, number of leaves and leaf area were noticed to be better in rain shelter grown plants, during both seasons. Early spike emergence [Oscar (S1- 87.35 days, S2- 73.25 days), Summer Sunshine (S1- 61.90 days, S2- 56.22 days) and White Prosperity (S1- 72.05 days, S2- 62.08 days)], shorter duration from spike emergence to opening and longer blooming period [Oscar (S1- 9.03 days, S2-10.08 days), Summer Sunshine (S1- 11.68 days, S2-13.03days), and White prosperity (S1- 9.68 days, S2-12.05 days)] were noticed in rain shelter grown plants. Total duration of the crop was shorter in rain shelter during both seasons. Spike length, spike diameter, rachis length, number of florets per spike [Oscar (S1-10.35, S2-12.00), Summer Sunshine (S1-11.38, S2- 13.80) and White Prosperity (S1-9.23, S2- 11.57)], floret size and number of florets opened at a time were observed better in rain shelter grown plants, during both seasons. Vase characters were also found to be superior in rain shelter grown plants. Rain shelter grown plants of Oscar (S1-5.00 days, S2-6.00 days), Summer Sunshine (S1-6.67 days, S2- 8.67 days) and White Prosperity (S1-3.3 days, S2- 4.00 days) recorded significantly more vase life, during both seasons. Corm yield recorded were maximum in plants grown in rain shelter. Cormel yield recorded was maximum in rain shelter for Oscar and White prosperity where as for Summer Sunshine, maximum cormel yield was observed in open field. Among the varieties, Summer Sunshine had better performance with respect to most of the vegetative, spike and vase characters, compared to other varieties, both in rain shelter and open field. Oscar recorded relatively higher floret size ( S1-9.47 cm, S2-10.31 cm) as well as cormel yield ( S1- 14.71, S2- 21.63) compared to other varieties, during both seasons in both growing conditions.
The results showed that spike qualities as well as corm yield can be enhanced by rain shelter cultivation. It was also noticed that November planting was found to be better than May planting, in order to obtain quality spikes as well as good corm yield in gladiolus under Vellanikkara conditions.
For post harvest studies, gladiolus spikes were harvested when the first floret showed colour. Spikes were subjected to the post harvest treatments - pulsing, holding, storage and packing. Among the pulsing solutions Sucrose 20% + 8 HQC 200 ppm was found to be better than other treatments for all the varieties, with respect to percentage of fully opened florets , percentage of unopened florets, longevity of individual florets (Oscar -1.8 days, Summer Sunshine – 3.8 days and White prosperity- 2.25 days), number of florets opened at a time, water uptake and vase life.For all the varieties, holding solution of Sucrose 5% + AgNO3 50 ppm was found to record the maximum percentage of fully opened florets, longevity of individual florets, water uptake and vase life (Oscar -7 days, Summer Sunshine - 9 days and White prosperity- 7days).
Maximum percentage of fully opened florets, longevity of individual florets, water uptake and vase life were observed in spikes stored at 80C, for all the varieties. The spikes packed in polypropylene sheet exhibited the highest percentage of fully opened and partially opened florets, longevity of individual florets, number of florets opened at a time, water uptake and vase life (Oscar-9 days, Summer Sunshine- 9.75 days and White prosperty- 8 days). Nature of spike bending of all the varieties was not significantly influenced by pulsing and holding solutions, packing and storage.
The post harvest studies revealed that pulsing of gladiolus spikes with sucrose 20 percent and 8- HQC 200 ppm for 3 hours, packing with polypropylene sheet, storing at 80C for 24 hours and holding in Sucrose 5% + AgNO3 50 ppm solution can significantly improve the vase characters of gladiolus.