STUDIES ON VARIABILITY AND MANAGEMENT OF SAFPLOWEIZ (Cartlrat~tus tiizctorius Linn.) WILT INCITED BY Fusariurn oxysporunt f.sp. cartlzairti KLISIEWICZ AND HOUSTON"
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Date
2004
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Professor Jayashankar Telangana State Agricultural University
Abstract
Variability among eleven isolates of Fusar.ium oxysporunz f.sp. cai-fhami, the causal agent of safflower wilt collected from different locations of Andhra Pradesh, Maharashtra and Karnataka in India was studied with respect to cultural, mo~hological characters, pathogenicity and protein profiles. In addition to these, biological control of the disease using the local isolate was also studied. Significant variation was observed with respect to size of microconidia, macroconidia and chlsunydospores of FOC isolates when grown on potato dextrose agar (PDA) medium. The size of micro and macroconidia ranged fio~n 8.02 -14.76 x 2.66 - 2.93 p and 17.40 - 26.82 x 4 - 4.53 pl. Longest microconidia (14.76 pm) was produced by the isolate FOC 1 l(Annigeri) and shortest microconida (8.02 pm) by the isolate FOC 8 (Aurangabad). Largest macroconidia (26.82 pm) was produced by the isolate FOC 5 (Parbhani I) and shortest macroconidia (17.46 pm) were produced by isolate FOC 7 (Solapur). The diameter of chlamydospores of isolates ranged from 5.83 pm to 9.50 pm. The isolate FOC 3 (Latur) produced largest chlarnydospore (9.30 pm), while the isolate FOC 1 (DOR) produced smallest chlarnydospore (5.83 p). No distinct variation was observed with shape of microconidia, nlacroconidia and cl~lan~ydospores of test isolates. Variation was observed in colony characters, colony growth, mycelial dry weight and sporulation among the test isolates. The isolates FOC 1 @OR), FOC 2 (Tandur) and FOC 8 (Aurangabad) produced fluffy white mycelium with whitish pink pigmentation while FOC 3 (Latur), FOC 4 (Phalton), FOC 6 (Parbhani 11) and FOC 11 (Annegiri) produccd coltoliy wliitc n~yceliun~ witti whitish pink pigmentation. ?'he other isolates FOC 5 (Parbhani I) and FOC 10 (Akola JI) produced white fluffy n~yceliunl with whitish yellow pigmentation and in addition zonation was observed in FOC 5 isolate collected from Parbhani. Isolate FOC 7 (Solapur) produced white cottony mycelium and FOC 9' (Akola 1) produced fluffy white mycelium without any pigmentation when grown on PDA medium. The colony diameter ranged from 5 1.60 mm (FOC 8) to 84.40 mm (FOC 9) seven days after incubation at 25 k 1 OC on PDA. The mycelial dry weight of FOC isolates ranged from 56.0 (FOC 8) to 252 mg (FOC 9) on potato dextrose broth (PDU) 10 days after incubation at 25 + 1°C while, number of microconidia ranged foml 4.80 to 28.20 x lo4 / mm2 and macroconidia ranged from 1.40 to 6.80 x 1 o4 /jmt1l2 011 PDA medium 15 days after incubation at 25 i: 1 "C. Pathogenicity test with the isolates of F. o. f.sp. car/l~anti sllowed differential reaction on moderately resistant safflower cvs. HUS-305 and A- 1. Whereas, the cvs. Manjira and Nira were susceptible to all the test
isolates. Wilt incidence ranged from 2 1 to 66.66 per cent in moderatelv 4 resistant cvs. HUS-305 and A-i, while in susceptible cvs. Nira and Manjira, wilt incidence was in the range between 73.33 and 100 oer cent. The isolates FOC 1 and FOC 2 induced >50 per cent wilt. while - the isolates FOC 4 and FOC 11 induced 21 - 40 per cent wilt in moderately resistant cv. HUS-305. The isolates FOC 1, FOC 4 and FOC 10 induced >50 per cent wilt and FOC 3, FOC5, FOC 8 and FOC 11 isolates induced 21 to 50 per cent wilt incidence in moderately resistant cv. A-i. In electrophoretic studies, all the isolates of FOC showed five con-i.:?on protein bands between molecular weights of 25 KDa to 45 kDa. The isolates FOC 3 (Latur) and FOC 9 (Akola I) showed common protein banding pattern between n~olecular weights 66.2 to 116 kDa. A total of nineteen bands were present in FOC 3 (Latur) isolate which was less virulent. Whereas, seven bands were seen in the isolate FOC 1 (DOR) which was more virulent than the other test isolates. b7 vinv evaluation of native isolates of T. viride, T. harzianum and P. fluorescens against F. o. f.sp. carthami by dual culture technique revealed that, T viride was found superior in inhibiting the mycelial growth of the test isolates of the pathogen as compared to T. harzianum and P. fluorescens. All the treatments involving bioagent, Zviride (native isolate) have recorded significantly less incidence of wilt in safflower cv. Nirr: and enha~~ced sigrlificantly the per cent seedling germination, shoot and root lengths and d~y weight compared to the pathogen check and uninoculated control.
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