DENTIFICATION OF NEW SOURCES OF RESISTANCE TO RICE GALL MIDGE BIOTYPES PREVAILING IN TELANGANA, INDIA

Abstract

A total of 52 rice germplasm lines along with resistant and susceptible checks were evaluated against rice gall midge, Orseolia oryzae (Wood-Mason) biotype1 under greenhouse conditions at the ICAR-Indian Institute of Rice Research, Rajendranagar, Hyderabad and under field conditions against biotype 3 at the Regional Agricultural Research Station (RARS), Jagtial and biotype 4M at RARS, Warangal during Wet seasons 2014 and 2015. Field screening for biotype 3 and 4M was carried out under natural infestation in endemic areas and observations were recorded at 30 and 50 days after planting. In greenhouse screening germplasm lines, (15 to 20 days old seedlings) were infested with 25 mated female gall midge adults and scoring for damage was done when at least 50% of the TN 1 plants (susceptible check) exhibited damage symptoms as silver shoots. Data on the total number of plants, plants with silver shoots and the number of silver shoots per plant were recorded. Percent plant damage was calculated. Plants with <10% plant damage were rated as resistant. Five germplasm lines viz., CR 2613-1-1-1-5-1, CR 2615-1, JGL 11470, JGL 11727 and Sukaradidhan 1 were identified as resistant to biotype 1. Of these, JGL 11727 and Sukaradidhan 1 exhibited HR+ and CR 2615-1 and JGL 11470 showed HR- reaction after gall midge infestation. Intivadlu was found resistant against biotype 3. None of the tested lines exhibited consistent resistant reaction across seasons against biotype 4M.