Ex vitro establishment of gladiolus (Gladiolus grandiflorus L.)

Abstract

Studies were conducted to standardize ex vitro establishment techniques in Gladiolus grandiflorus L. variety Vinks Glory during 2002-2004 in the Department of Pomology and Floriculture, College of Agriculture, Vellayani. The effects of various potting media (sand, soilrite, sand: soil, sand: soil: coirpith, sand: soil: leaf mould), triazole (0, 4 and 8 mg/l), mycorrhizae (Glomus fasciculatum and Glomus monosporum) and height of potting media in the container (4 and 6 cm) on ex vitro establishment of the micropropagated plantlets were studied. Among the different potting media used for ex vitro establishment, soilrite recorded higher survival rates of 86.11 and 80.55 per cent after the first and second fortnight respectively. Triazole application improved the survival rate over non-treated plants. Triazole at 4 and 8 mg/l concentrations recorded 54.16 and 55.83 per cent survival respectively after one month of planting. The two mycorrhizal fungi tried in the study exerted differential effect on survival. Colonization of the roots by mycorrhizal inoculation was found to be high and this enhanced the survival rate of plantlets. Leaf number and plant height was found to be affected by triazole application. Triazole treated plants exhibited a decrease in number of leaves and a reduced plant height due to its growth retarding action which in turn resulted in reduced leaf area index. Triazole application delayed leaf production of plants due to inhibition of leaf expansion. Fresh weight, dry weight, CGR and RGR were found to be high in treatments with triazole application.

Growth of mycorrhizal fungi was affected by different potting media. But triazole treatment did not affect the colonization of AMF. Among the two mycorrhizal fungi, Glomus fasciculatum inoculated plants exhibited higher plant height, increased number of roots, delayed emergence of leaf and low stomatal conductance. A decrease in stomatal conductance observed during the later stages of planting out indicate the acclimatization of the plantlets to the ex vitro conditions. Potting media, triazole, mycorrhizae and their interactions affected the stomatal conductance significantly. Height of potting media in the container did not influence the survival and growth parameters. The estimated cost of hardened plants ranged from Rs. 4.50 to 5.25. Eventhough the cost is higher than that of conventional propagation method, this can satisfy the need for large scale production of disease free planting material.