Weather-based empirical model to predict infective sporidial stage of Tilletia indica during wheat crop season
232 / 88
Authors
-
GURBIR KAUR, SATVINDER KAUR* and S.S. HUNDAL
Abstract
Investigations on the effect of weather parameters on the survival of colony formed by the germinated teliospores of Tilletia indica (Mitra) Mundkur and the infective sporidial stage were made in the wheat field at Ludhiana. Actively growing colonies incubated in the wheat field remained viable up to 19 days, when mean temperature for this period was 10°C (minimum), 22°C (maximum) and RH 58-94%. Best fit third degree polynornlal functions explained the observed variation with maximum temperature (X). in the survival of T.indica colony (y) = -0.025X3+ 2.197X2- 64.01X+ 629.45, (R2 = 0.95). The sporidia were produced through out the wheat crop season and the number formed peaked during heading of wheat crop. Maximum number formed were 170 per 200x, when the colony was incubated from 5pm to 9am ( night regime), when temperature was 7.4-8.2 °c, RH 100% and GOD 11.2 °c days, in both the years. In the day regime (9am - 5pm), highest number of sporidia detected was 40 sporidia per 200x, when temperature was 18.4 °c (maximum), 56% RH and GOD 11.6°C days in 2004. Best fit polynomial equations for highest sporidial counts (y) were obtained with maximum temperature (X), for night regime it was: Y=0.3403X3_22.63X2+ 482.87X3174.6 (R2=0.45) and for the day regime Y=0.1835X3_12.628X2+ 282.64X- 2030.3 (R2 = 0.62), which validated the observed and expected number of sporidia formed, although R2value was low as compared to the model which was developed using mean weather parameters for the various c asses of sporidia produced V= -10.475X3+ 73.33X2- 126.59X + 172.6, when R2=0.99. Number of favourable days (X) when optimum conditions were prevalent for the maximum production of the infective stage were identified in the agro-metrological data from 1996-2005, during heading of wheat and correlated Significantly with incidence of Karnal bunt (Y) observed in the farmers field and best fit polynomial equation Y = -0.0207X3 + 0.157X2- 0.0606X + 0.0187 (R2 = 0.99), developed explained 99% variations.
Downloads
Issue
Section
License
For Authors
As soon as an article is accepted for publication, authors are requested to assign copyright of the article (or to grant exclusive publication and dissemination rights) to the publisher (Indian Phytopathlogical Society). This will ensure the widest possible protection and dissemination of information.
For Readers
While the advice and information in this journal is believed to be true and accurate at the date of its publication, the authors, the editors, nor the publisher can accept any legal responsibility for any errors or omissions that may have been made. The publisher makes no warranty, express or implied, with respect to the material contained herein.
All articles published in this journal are protected by copyright, which covers the exclusive rights to reproduce and distribute the article (e.g., as offprints), as well as all translation rights. No material published in this journal may be reproduced photographically or stored on microfilm, in electronic data bases, on video disks, etc., without first obtaining written permission from the publisher. The use of general descriptive names, trade names, trademarks, etc. in this publication, even if not specifically identified, implies that these names are protected by the relevant laws and regulations.