Evaluation of sorghum genotypes for variation in canopy temperature and drought tolerance

dc.contributor.authorMutava, Raymond Ngao
dc.date.accessioned2012-08-23T20:47:16Z
dc.date.available2012-08-23T20:47:16Z
dc.date.graduationmonthDecemberen_US
dc.date.issued2012-08-23
dc.date.published2012en_US
dc.description.abstractSorghum (Sorghum bicolor L. Moench) is the fifth most economically important cereal crop grown worldwide and adapted to a wide range of climatic conditions. Drought stress has been ranked as one of the most significant causes of crop yield loss with its effects on yield and yield components. Conservative water use by plants is one of the strategies that can be used as a drought coping mechanism. The slow wilting trait has been associated with conservative water use and has been found in some sorghum genotypes. The purpose of this study was to use canopy temperature to screen for drought tolerance in sorghum, evaluate water use efficiency for slow wilting sorghum genotypes and determine variability in root morphology and response to drought among sorghum genotypes. Canopy temperature studies were conducted under field conditions using infrared (IR) sensors while water use efficiency and root studies were conducted under greenhouse conditions. Our results showed a distinct separation in canopy temperature among genotypes under field conditions at 2:00 pm to 6:00 pm. Midday canopy temperature depression (CTD) was positively correlated to yield (R2 = 0.19) and harvest index (R2 = 0.11). CTD was also stable for all the genotypes during the period from 1:00 pm to 7:00 pm. There was a negative correlation between CTD and crop water stress index (CWSI) (R2 = 0.34) and a positive one between canopy temperature and CWSI (R2 = 0.50). Evaluation of genotypes for water use efficiency revealed significant variability among sorghum genotypes in the amount of water used (10.48 – 13.52 kg) and transpiration efficiency (TE) (2.64 – 7.11 g kg-1) among genotypes. Slow wilting genotypes were high in TE. Rooting depth increased for some genotypes under drought stress with genotype SC1124 recording the largest increase (180%). Total root length for some genotypes increased by 11 – 113% with genotypes SC224 and SC1019 recording the greatest increase. There was a positive correlation between water used and root length (R2 = 0.21). These results show that there is potential for selection of drought tolerance in sorghum and that genotypes with the slow wilting traits are efficient in water use.en_US
dc.description.advisorP.V. Vara Prasaden_US
dc.description.degreeDoctor of Philosophyen_US
dc.description.departmentDepartment of Agronomyen_US
dc.description.levelDoctoralen_US
dc.description.sponsorshipKansas Sorghum Commission, the Centre for Sorghum Improvement, International Sorghum and Millet Collaborative Research Support Program of USAID, Department of Agronomy - Kansas State University.en_US
dc.identifier.urihttp://hdl.handle.net/2097/14506
dc.language.isoen_USen_US
dc.publisherKansas State Universityen
dc.subjectCanopy temperatureen_US
dc.subjectSorghumen_US
dc.subjectTranspiration efficiencyen_US
dc.subjectDrought stressen_US
dc.subjectRoot lengthen_US
dc.subjectCrop water stress indexen_US
dc.subject.umiAgronomy (0285)en_US
dc.subject.umiPlant Sciences (0479)en_US
dc.titleEvaluation of sorghum genotypes for variation in canopy temperature and drought toleranceen_US
dc.typeDissertationen_US

Files

Original bundle
Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
RaymondMutava2012.pdf
Size:
7.45 MB
Format:
Adobe Portable Document Format
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.62 KB
Format:
Item-specific license agreed upon to submission
Description: