Location: Hard Winter Wheat Genetics Research Unit
2009 Annual Report
Winter wheats were inoculated with sporidial suspensions derived from a mixture of isolates of the Karnal Bunt pathogen (Tilletia indica) by the syringe inoculation method under natural field conditions in Ludhiana, Punjab, India. The 4th, 5th, and 6th Winter Wheat Karnal Bunt Screening Nurseries (WWKBSN) were vernalized for 21 days and also planted early (in the month of October, 2008). All the lines could be inoculated at the appropriate stage, i.e. at awn emergence. Frequent irrigation was carried out to maintain adequate humidity for disease development.
All 21 lines of the 4th WWKBSN which had scored less disease in previous years could be inoculated at the appropriate time due to proper vernalization and increasing photoperiod. This nursery was planted and evaluated in the Plant Biotechnology section during 2005-06 and the resistant lines were re-evaluated in 2006-07 and 2007-08 under field inoculation conditions. Based on the evaluation of last three years, 4 experimental wheat lines (line numbers 224, 226, 360 and 383) developed <3% infection and could thus be rated as resistant to Karnal bunt. These lines can be utilized in breeding future lines. From 345 lines of 5th WWKBSN, 102 were re-evaluated during 2008-09. A total of 55 lines have been retained for subsequent evaluation in the forthcoming season. Lines scoring 5-10% infection have been retained as disease was too high under artificial inoculation conditions during the current year. From 447 original lines in the 6th WWKBSN, 225 were reevaluated. One hundred lines showing less disease than average have been retained for subsequent evaluation. The 7th WWKBSN received during 2008 was received late and was planted late. The lines were inoculated in last week of March / 1st week of April when temperature has risen. However, out of 251 lines 151 scoring less disease have been retained for evaluation in next season. Efforts will be targeted to vernalize the lines of all the nurseries received up to 2009 and reaction of the lines from 4th, 5th and 6th WWKBSN will be concluded during 2009-10.
Progress on this agreement is monitored by regularly discussing program goals, approaches, and results (teleconference, email) and by reviewing annual accomplishments reports.