Biochemical Changes and Microbial Profiles Affecting Quality and Vase Life of Cut Gladioli (Gladiolus Grandiflorus L. ‘Fado’) Following Pulsing and Cold Wet Storage

Abstract

Floriculture in Kenya remains among the top three foreign exchange earners. Gladiolus is one of the famous cut flowers in the world. Annual losses amounting to 30,000 metric tonnes valued at USD; 166.6 is incurred by farmers due to postharvest challenges. The aimof this study was to determine the vase life and quality parameters of cut Gladiolus grandiflorus L. cv.‘Fado’ as affected by pulsing with 600 ppm 8-hydroxyquinoline sulphate plus 5% sucrose prior to wet cold storage duration(0 – 5 days). The Gladiolus were grown in the open field from corms at the Horticulture Research and Teaching Field, in the department of Crops, Horticulture and Soils, Egerton University, Kenya, during the season of September to December 2014. A two by six factorial experiment embedded in a Completely Randomized Design with four replicates was adopted using Proc GLM model in two way ANOVA. Differences in means were determined using Tukey’s test at 5% level of significance. Pulsing treatments and interactive wet cold storage durations significantly affected cut Gladiolus quality parameters including fresh weight (P< 0.0031; 11.67% increase).,dry weight (P˂ 0.0272 ;17.62% increase)., mean water uptake (P < 0.0001; 38.14% increase)., opened florets (P˂ 0.00095; 59.8% increase) and number of unopened buds (P <0.0256 ; 61-28.88% reduction). The pulsing and cold storage treatments and their interaction significantly (P˂ 0.0001., P˂0.0003.,P˂0.0001 respectively) affected the vase life of the cut Gladiolus (11.5 ± 0.0.148 days versus 4.75 ± 0.148 days; 142% increase).The pulsing treatment coupled with wet cold storage and their interactive effects significantly (P < 0.0001) affected the concentrations of the senescence biomarkers: Total Free Amino Acids, (P<.0001; 21.97% reduction)), Total Soluble Sugars (P < 0.0001; 101.16% increase) and Total Starch(P <0.0001; 309.39 % increased) on the third day in the vase compared with the control. The levels of Total Phenols, anthocyanins and microbial proliferation were also significantly affected (P< 0.0003 (104.14% increase)., P ˂ 0.0012 (26.98% increase)., P < 0.0001 (6.032% reduction) respectively) on the third day in the vase in pulsed spikes wet cold stored for 3 days.Gladiolus cut flowers can be wet stored at 3 ± 1°C up to a maximum of 4 days without any adverse effect on their subsequent vase life and quality. Small scale farmers can adopt pulsing cutG. grandiflorus cv.Fadowith subsequent storage of upto 4 days at 3 ±1 OC to manage bulking and transportation of their produce to reduce postharvest losses. This may increase domestic livelihood withenhanced foreign exchange and consequently food and job security in Kenya.Knowledge from this study will augment existing technologies in improving quality and market value of Gladiolus cut flower.