Studies on, Fusarium Moniliforme a Causal Organism of Bakanae Disease of Rice

Abstract

Rice is an important food crops in the world, forms the staple diet of 2.7 billion people. Rice belongs to the family of Gramineae (Poaceae) and genus 01yza. Rice possesses high nutritive values containing moisture 13.6g, protein 6.38g, fat 0.5g, minerals 0.6g, carbohydrates 78.2g, calcium 10 mg, fibre 0.2g, phosphorus 160mg, iron 0.7mg and vitamins. It is grown in all the continents except, Antartica occupying 154 million ha of area, producing 600 million tons of rice with an average productivity of 3.90 tones ha·'. In India, it is cultivated on an area of 44.1 million ha which is maximum among all rice growing countries having annual production of about 131.3 million tons with productivity of 3.0 tones ha·'. It accounts for about 42% of total food grain production and 55% of cereal production in the country. Uttar Pradesh is the largest rice growing state after West Bengal but its productivity is low. In U.P. rice is grown on an area of about 5.69 million ha with a production of 11.7 million tones and productivity of about 2.06 tones ha·'. Rice production affected by many diseases and insect pest. Among the diseases a fungal disease known as bakanae disease is the most impot1ant and causes severe losses in rice yield particularly in basmati rice. It is caused by Fusariummoniliforme(Gibbrellafujikuroi) which produce gebbrelin hormones. !tis growth regulating hormone, it increase the height of plant. The first symptoms observed in seedling stage of rice plant. The seedling appears to be elongate, thinner and slightly yellow as compare to healthy green seedling. In the north India this disease called Jhanda disease. Variability was observed in Fusarium moniliforme isolates at all parameters including colony color, and colony size. Colonies of 4 isolates were found fluffy, while, two were compact. Initially the color of all the isolates was white which changed subsequently with different tinges of color i.e. white, bluish white, brownish white and creamy. Shahajanpur and APEDA isolate having the radial growth 82 mm and 79 mm respectively. The lowest growth was noted in isolates PR-113 and Sugandha-4 with 60 mm and 68 mm respectively. Effect of different temperature on the growth of pathogen was also studied. Temperature I5°C, 20° C, 25°C, 30°C, and 35°C tested under laboratory condition . Temperature at 25°C and 30°C supported best mycelial growth of the pathogen, which were 85.00 mm and 80.00 mm respectively. There was gradual decrease in mycelia growth of the pathogen at temperature above 30°C.The effect of different pH on the mycelial growth was studied on potato dextrose agar medium, at different pH values viz. 4.5, 5.5, 6.5, 7.5, and 8.5. Maximum growth of the fungus was recorded at 7.5 pH. There was significant reduction in the growth of the pathogen at pH lower than 5.5 and higher than 8.0. Six different culture media were also tested for the growth of pathogen. The lowest growth rate was noted on Asthana& Hawker's medium.The effect of different colour light as Blue, Red, Yellow, Green and Black on the mycelial growth of pathogen. Some different colors of light are effective for inhibiting the growth of the pathogen. The maximum percent inhibition was observed in red color ( 13.33%) and blue color (11.11%).The minimum percent inhibition was observed in black color (4.44) and green colour ( 4.44 ). Present investigation gives several important information regarding, bakanae disease of basmati rice and its causal organism, which is serious threat to the farmers of basmati rice. This information may be valuable for the further study on this pathogen as well as for developing management strategy for bakanae disease.