Gupta, OmPatil, Minakshi Ganeshrao2016-06-302016-06-302015http://krishikosh.egranth.ac.in/handle/1/68318Chickpea (Cicer arietinum L.) is the most important pulse crop among the major Rabi pulses of India. Fusarium wilt which is caused by Fusarium oxysporum f. sp. ciceris is considered to be the most devastating disease of this crop. Among the different seven isolates used in this study, Isolates I-19 and I-28 resulted 100 per cent mortality within 11 days whereas, isolates I-13 and I-80 resulted 100 per cent mortality within 16 and 17 days respectively on highly susceptible cultivar JG 62. Whereas, in highly resistant cultivar JG 315 isolates I-19 and I-28 showed resistant reaction, I-20, I-13 and I-1 showed moderately resistant whereas, I-4 and I-80 showed susceptible reaction within 25 days after transplanting. In case of cultural and morphological characters, growth pattern among the isolates varied as fluffy, partial fluffy, cottony growth, partial submerged and submerged. Studies on growth rate i.e. colony diameter and time required for maximum spore production exhibited the maximum and fast growth was obtained by Isolates I – 20 and I – 13 within seven days of incubation whereas, the isolates I-4 showed slow growth on 9th day. Macro conidia varies from 1.7 to 9.1x105on 5th and on 7th DAI whereas, microconidia possessed 2.0 to 9.1x105 after 5th and 7th DAI. Isolates I-1 showed minimum and I-13 showed maximum dry weight of mycelial mat on liquid media respectively. The highest growth was observed in Czapek’s Dox agar and on PDA among the all tested medium. While, Ashby’s agar was less favorable for the growth of many isolates. Temperature ranged from 25-30OC and pH ranged from 6.0-6.5 exhibited best for the growth and sporulation of F. oxysporum f. sp. ciceris. Seedling reaction of ten chickpea differential genotypes against races and variants of F.oxysporum f. sp. ciceris revealed the existence of pathogenic variability among these isolates. The cultivar JG 74 and JG 315 showed resistant reaction to almost all isolates and cultivar JG 74 showed susceptible reaction to isolate I-19 whereas, cultivar JG 62 exhibited susceptible reaction to all isolates. Pathogenic variation by in-vitro screening through root feeding of pathotoxin revealed that the genotypes JG 74, JG 11 and JG 322 took 12 days for wilting, while the three genotypes JG 63, JG 14 and JG 24 took 10 days. The remaining two genotypes JG 16 and JG 130 survived for 4 and 6 days whereas, JG 62 died on the 6th day after transplanting. On the other hand, all seedlings of JG 315 survived for 14 days, without showing any symptoms of wilting. Co-efficients of the seven isolates of F. oxysporum based on SSR markers ranged from 0.7 to 0.3 among all the genotypes. Accessions of isolates I-20 and I-13 showed the highest similarity index (0.7), while the lowest similarity index (0.3) was found in between isolates I-80 and I-1. The root exudates of the susceptible cultivar JG 62 and late wilting cultivar K 850 did not inhibit colony growth and spore germination of all isolates of FOC whereas, it was strongly inhibited by root exudates of JG 315. On the contrary, the root exudates of JG 74 resulted higher colony growth and spore germination percent. In the histopathological study distinct browning of the vascular cylinder in the infected JG 62 showing the advance of disease progression from root to shoot while the infected JG 315 plant did not show any prominent browning in the vascular cylinder. Studies on host resistance under multiple disease sick field led to conclusion that among 285 entries two entries showed less than 10 percent mortality and may be considered as resistant, 11 entries exhibited 10.1 to 20 percent mortality and regarded as moderately resistant during 2013-14 however, during 2014-15, six entries showed less than 10 percent mortality and considered as resistant, 14 entries exhibited 10.1 to 20 percent mortality and regarded as moderately resistant. The cultural, morphological and molecular study of New variant showed the similar virulence, pathogenicity and growth pattern on PDA with Race 4. The effect of temperature and pH on growth and sporulation of new variant was similar as on Race 1. However, t he root exudates and molecular study grouped this variant in Race 2. Hence it can be concluded that conformity of any pathogen needs to addresses the both conventional (cultural and morphological) and molecular approach to come out with its appropriate ide ntifications and for further emulation of its management.enThesis