06-08-2013, 04:52 PM
Effect of temperature and relative humidity on the development of Spot Blotch of wheat caused by Bipolaris sorokiniana in Intermediate zone of J&K
ABSTRACT
An experiment was conducted at Regional Agricultural Research Station, Rajouri (J&K) for two consecutive years durinsg Rabi season of 2008-09 and 2009-10. Nineteen varieties viz. VL-804, VL-872, HS-565, HPW-276, HP-1633, PBH-317, VL-900, HPB-266, HS-295, UP-2694, VL-738, HD-2937, VL-895, UP-2330, WH-2008, DL-784-3, PRW-317, PBW-313 and HPW-266 were sown on two different dates at 25 days intervals (20th October and 15th November) with three replications having a plot size of 1x1m using split plot design. The meteorological observations recorded from sowing to maturity from agro-meteorological observatory at Regional Agricultural Research Station, Rajouri. There was significant difference in varieties and dates of sowing, earlier sown crop (20th Oct.) recorded lower mean disease incidence (15.34%) along with mean grain yield 20.27 q/ha of all cultivars while, crop sown on 25th November have higher disease incidence (48.28%) along with grain yield of 17.24 q/ha. Among all cultivars VL-738 was found resistant than other cultivars recorded least disease incidence in both dates of sowing along with highest grain yield (mean disease incidence 8.57% and mean grain yield 28.17q/ha mean of both dates). However, cultivar WH-2008 was found highly susceptible than other cultivars recorded highest mean disease incidence (54.61%) along with lowest mean grain yield (14.09 q/ha). The disease incidence was higher in year 08-09 (20th Oct. 16.41% along with 19.34 q/ha grain yield and 25th Nov. 49.64 % along with 16.54 q/ha yield) in comparison to year 09-10 (20th Oct. 14.26% along with 11.2 q/ha grain yield and 25th Nov. 46.92 % along with 17.94 q/ha yield). It is found that, if the temperature and relative humidity increased there was a corresponding increase in disease development.