Physiology of Rosa ‘Gruss-an-teplitz’ following treatment with rhizobacteria (PGPR), salicylic acid (SA) and zinc sulphate

Fresh cuttings from 2-year-old rose cultivar Rose gruss-an-teplitz was treated with 2 PGPR used as seed soaking treatment and with Zinc sulphate added to the rhizosphere soil or treated with Salicylic acid (SA) as foliar spray was sown both in the field and in pots (under sterilized condition). Physiological parameters were recorded at flowering. All the treatments promoted growth parameters and improved the quality of rose water. However, greater increase in all growth parameters were recorded in Pseudomonas putida + Salicylic acid treatment. Potted grown plants also showed significant stimulation in growth and reproductive parameters; Bacillus cereus being highly effective. The treatment effects were greater in summer but in winter the % increase was also significantly greater over control. Organoleptic analysis of rose water revealed that treatment with Pseudomonas putida + Salicylic acid (SA) imparted maximum aroma and sweetness in field grown plants while Bacillus cereus inoculation proved most effective in potted plants. Plant was more responsive to treatments in summer than that of winter. Rose petal water from potted plants of winter revealed higher aroma in winter as compared to summer. Similar trend was noted in case of field grown plants. The incidence of disease was not recorded in treated plants particularly in presence of SA. Both the PGPR and SA act synergistically and can be applied to boost growth, yield and quality of roses. This is the first report regarding the effect of PGPR, defense hormone SA and Zinc sulphate alone and in combination on roses. The investigation revealed that PGPR can augment the effectivity of Zinc sulphate and SA on growth and reproductivity of rose as well as on its quality e.g., flavor and sweetness of rose water. The combined treatments may be implicated to enhance productivity and quality of roses.