Post harvest management of Karnal bunt (Tilletia indica) in wheat by mechanical seed processing
2017
KUMAR, ASHWANI | GUPTA, ANUJA
Karnal Bunt (Tilletia indica Mitra) is a designated disease and a limiting factor in wheat export because most countries regulate Karnal bunt (KB) pathogen as a quarantine pest. The seed must be threshed and examined for KB infection as detection of disease in the field is difficult. Therefore, the post harvest management of KB in wheat seed production through mechanical processing is very important. Pre-cleaner and screen grader of the processing line removed 83.1, 61.4 and 77.8% of total KB infected seed present in the seed lot and reduced KB infection from 1.42 to 0.24, 4.27 to 1.65 and 3.57 to 0.79% in 2012-13, 2013-14 and 2014-15, respectively which is much higher than the permissible limit of 0.05%. Hence, a total of 18 combinations, comprising of three deck slopes (S1- 20, S2- 2.50, S3 -30), three feedings (F1- 5 kg, F2- 10 kg, F3- 15 kg per minute) and two output settings of the deck width (O1- 45cm, O2- 43cm) of specific gravity separator were studied with an objective of minimizing Karnal bunt infected seed in the seed lot within permissible limits. Minimum KB infection in final product (0.04, 0.28 and 0.11%), maximum seed recovery (12.58, 12.78 and 12.72 kg/minute) with 84.1, 86.4 and 85.4% recovery efficiency was obtained by the treatment S1F3O1(slope of deck 20, feeding 15 kg/minute, output deck width 45cm) in 2012-13, 2013-14 and 2014-15, respectively. Mechanical processing reduced KB infection by more than 90%, depending on the intensity of infection, as well as improved seed quality, i.e. seed germination improved by 7.90% and physical purity by 2.22%.
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