Evaluation of gladiolus (Gladiolus grandiflorus L.) cultivars for resistance against botrytis blight caused by Botrytis gladiolorum

Gladiolus is a commercial flower crop and can be grown in varying climatic conditions. Botrytis blight caused by Botrytis gladiolorum Timm. is one of the most common and destructive diseases of gladiolus that causes great losses every year. Methods to manage this devastating disease have relied on identification of resistant cultivars through screening techniques. An investigation was carried out to study the performance of sixty-five cultivars of gladiolus under artificial epiphytotic conditions under laboratory conditions and in the field for resistance against the disease. None of the varieties was found to be immune to infection even after 4 days of incubation. Twenty eight were found to be moderately resistant (disease reaction: >1.0–2.0); whereas thirty seven showed a moderately susceptible reaction (disease reaction >2.0–3.0). After 8 days of incubation, three varieties were found to be moderately resistant (disease reaction: >1.0–2.0); whereas twenty one had moderately susceptible reaction (disease reaction >2.0–3.0) and forty one varieties were found to be moderately susceptible against the disease (disease reaction >2.0–3.0). In field conditions, four varieties, namely Dhanvantri, Jacksonville Gold, Nova Lux and Punjab Glance showed very good level of genetic resistance against the disease (disease reaction: ≤ 1.0). Seventeen varieties were found to be moderately resistant (disease reaction: >1.0–2.0); while, thirty five moderately susceptible to the disease (disease reaction >2.0–3.0). Nine varieties, namely Red Beauty, Regency, Snow Princess, True Yellow, Ratna Butterfly, Bis-Bis, Odysee, Hunting Song and Sancerre were found to be the most susceptible to infection (disease reaction: >3.0–4.0). As far as agronomic characters are concerned, cultivar Anglia was earliest (68.00 days) in spike emergence. Maximum plant height of 112.66 cm was shown by Pune Hybrid, whereas the cultivar Punjab Flame gave highest spike length.