Production of virus tested gladioli through in vitro and in vivo techniques

Gladiolus is a popular flowering crop throughout the world. In India its cultivation is of recent origin being only a few decades old. The state of Himachal Pradesh offers a tremendous scope for its cultivation because of varied climatic regions where farmers can produce cut flowers during the off-seasons for sale in North India. Production of gladioli has been in decline in recent years due to phytopathological problems. Among other diseases viruses have been causing considerable concern to the Gladiolus growers. Surveys conducted in the Solan district of Himachal Pradesh revealed that 100% of the plants of the cultivar Morala were infected with Bean Yellow Mosaic (BYMV) and Cucumber Mosaic (CMV) viruses, as evidenced by mosaic, mottling, chlorotic venation and necrosis on leaves. The viruses were found to be mechanically transmissible to Chenopodium amaranticolor. Plants free from these viruses were produced by meristem tip culture, heat therapy and using a biovirus inhibitor. Meristem tips varying in size from 0.5-0.7 mm gave 50% survival on half strength MS medium supplemented with 0.5 mg·l-1 BAP, and all the surviving meristems produced plants free from these viruses. In addition a hot water treatment of corms at 550C could also eliminate these viruses from the plants. The viruses could be eliminated from the crop by spraying infected plants with 9.0 mg·l-1 of root extracts of Asparagus adscendens. On the other hand, when explants from infected plants were grown on medium supplemented with the virus inhibitor, even a concentration of 7.0 mg·l-1 was found suitable for getting rid of BYMV and CMV.