Received: 09-07-2020 / Accepted: 30-11-2020
Acollectionof102VietnameseIndicatraditionalricevarietieswere screenedfordroughttoleranceduringthevegetativestagetoselectgenotypeswithhighdroughttoleranceforricebreedingprogram.Underthegreenhouseconditions,six-week-oldplantsweredroughttreatedbystoppingirrigationfor4weeks.Aftereachweekofdroughtstress,leafrelativewatercontent,slopeofleafrelativewatercontentanddroughttolerancescoreweremeasured.Theleafrelativewatercontentremainedhighafteroneweekofdroughtstress,significantlydroppedafter2weeks,slightlydecreasedafter3weeksanddisplayedavaluelessthan23.5%after4weeks.Theslopeofleafrelativewatercontentwasstronglyreducedatthesecondandfourthweeksofdroughttreatment.Afteroneweekofdroughtstress,mostofthegenotypesweretoleranttohighlytolerant.Thelevelofdroughttolerancedippedafter2and3weeksofstress,andnogenotypewithtolerancewasobservedafter4weeksofstress.After2weeksofplantrewatering,therecoveryabilityrangedfrom0-85.2%.Basedontheresultsobtained,13highlypromisingricegenotypeswereselectedforplantwaterstatus,droughttoleranceandrecoveryability,amongthem,G42,G115andG163wereconsideredasthemostpromisingtoleranttodrought.