Varietal evaluation and biochemical changes due to field incidence of Fusraium wilt in gladiolus genotypes

Abstract

Thirty gladiolus genotypes were evaluated for agronomic traits and natural screening to Fusarium wilt during 2015 and 2016. Among the genotypes, Suchitra × Melody took the minimum days (11.24) to bud sprout post planting, while Tha Barton registered 72 days for spike emergence. Pusa Unnati recorded the maximum spike and rachis length, while Pusa Manmohak, Pusa Red Valentine and Pusa Unnati recorded maximum number of florets per spike. Maximum field-life of spikes was recorded in Pusa Unnati followed by Pusa Red Valentine. After about 45 days of planting, different genotypes showed varied disease incidence (3.47-45.13%) and plant mortality index (0-35.47%). Genotypes, Swarnima, Pusa Unnati and Suryakiran were found more resistant to fusarium wilt, while Urmi and white Friendship were found highly susceptible. Leaves and corms were sampled at 75 days of planting for estimation of different biochemical parameters, namely, total chlorophylls, total sugars, total phenols, and malondialdehyde (MDA) content. The resistant genotypes had higher contents of total chlorophylls; higher phenols but lower TSS and MDA contents in corms. Negative correlations were estimated for DSI and biochemical parameters like total chlorophyll (r = -0.974**), total phenol (r = 0.925**). Positive correlations were reported among DSI and total sugars (r = 0.938**) and MDA content (r = 0.918**). Hence, these parameters can be employed as biochemical markers for screening of gladiolus genotypes for Fusarium tolerance..