Growth and quality of rose (Rosa hybrida l.) cultivars as influenced by poly film covers and different concentrations of calcium foliar feed

Abstract

Rose cut flower production contributes significantly to Kenya’s economy and its quality is therefore paramount for sustainability on the export market. Despite the tremendous contribution, profitable production of cut rose flower is limited by unsuitable growth conditions which lead to low quality produce. A study was set up at Egerton University to investigate sustainable ways to improve growth and quality of rose cultivars through integration of greenhouse growth conditions and calcium foliar feed. The experiment was laid down as a split split plot experiment in a randomized complete block design (RCBD) replicated three times. Poly film covers (UV-A clear, IR 504 and UV – A 205 / N) formed the main plot treatment with rose cultivars and calcium foliar feed forming the sub and sub-sub plot treatments respectively. Rose plants were established on raised bed at a spacing of 30 cm × 20 cm and mother shoot was bending done to induce sprouting of bottom breaks upon which production was based. Data collection involved measurement of growth variables and physiological parameters such as: physiological disorders, leaf chlorophyll content, dry matter partitioning and accumulation, anthocyanins and post- harvest physiology parameters. The collected data was subjected to analysis of variance (ANOVA) using SAS version 9.2 (SAS Inst., Inc., Cary, NC) computer package and significantly different means were separated using Tukey’s honestly significant difference (HSD) at P ≤ 0.05 %. The results showed that the poly film covers significantly affected the percent light transmission. The average light transmission over the production period was 1227 μmol .m-2. s-1, 840 μmol .m-2. s-1 and 976 μmol .m-2. s-1 under UV-A clear, IR 504 and UV-A 205/N respectively. Greenhouse microclimate significantly varied with the type of poly film. Mean air temperature of 41 °C, 35.2 °C and 32.8 °C were recorded under UV-A clear, IR 504 and UV – A 205 / N. Highest number of short stems < 40cm, was recorded under UV-A clear poly film for cultivar Red Calypso. Time taken between visible bud break and flowering differed a mong the cultivars between 43 and 50 for flushes I and II being 3-5 days shorter that the time taken under IR504 and UV-A 205/N. The combination of UV-A clear poly film, Red Calypso and 5.0 ml/L had the highest stem firmness (7.83). Red Calypso under the IR504 poly film with no calcium treatment had stems with the least firmness (5.0). The results of this study indicate that poly films and rose cultivars should be screened for suitability before adoption under different environmental conditions for production of quality rose cut flowers.