SPOROPHYTIC AND GAMETOPHYTIC SCREENING FOR FUSARIUM WILT RESISTANCE IN CARNATION (Dianthus caryophyllus L.)
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Date
2017-09
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University of Horticultural Sciences, Bagalkot. (College of Horticulture, Bengaluru).
Abstract
Twenty carnation genotypes were screened at their sporophytic level for resistance against three isolates of Fusarium wilt (Fusarium oxysporum f. sp. dianthi) viz., IIHR, Pune and Solan. Among the carnation genotypes inoculated with isolate-IIHR, Pune and Solan, the genotype Dark Dona recorded the highest per cent disease severity (67.33 %, 65.95 % and 63.82 % respectively), whereas, for the isolates- IIHR and Pune, the lowest per cent disease severity was recorded in the genotype Gioele (8.56 % and 8.98 % respectively). On the other hand, the genotype White Dona recorded the lowest per cent severity (11.68 %) for the isolate- Solan. Investigation on the role of secondary metabolites viz., flavonoids, phenols and plant defence enzymes viz., peroxidase, polyphenol oxidase, phenylalanine ammonia lyase and superoxide dismutase activity revealed that the genotypes Gioele and Praga found resistant to Fusarium wilt recorded higher levels flavonoids (44.74 and 42.10 mg CE/100g respectively), phenols (139.87 and 127.43 mg GAE/100g respectively), peroxidase (1.032 and 0.873 Δ abs/min/g FW respectively), polyphenol oxidase (0.897 and 0.827 Δ abs/min/g FW respectively), phenylalanine ammonia lyase (0.255 and 0.215 μg cinnamic acid/g/min respectively) and superoxide dismutase activity (8.87 and 7.465 units/gm FW respectively). Gametophytic screening of eight carnation genotypes in the presence of fusaric acid at 0, 0.5, 1, 2.5, 5, 10, 25 and 50 % concentrations revealed that the genotype IIHR-CG-202, recorded the highest germination per cent (33.15 %), relative changes in pollen germination per cent (68.44 %) and relative changes in pollen tube growth (70.94 μm) in the presence of fusaric acid.