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Title: Molecular and physiological dissection of heat tolerance during anthesis in rice (Oryza sativa L.)
Author: Jagadish, S. V. Krishna
ISNI:       0000 0004 2717 0894
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2007
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Human induced climate change is predicted to increase mean surface air temperature by 2.0° to 4.SoC by the end of this century. In the future, rice (Oryza saliva L.) grown in tropics may be exposed more frequently to temperatures >33°C than at present. If high temperature coincides with anthesis, the most sensitive stage of development, then yields will be reduced. Therefore, a novel protocol to screen for true heat tolerance during anthesis was developed and the. genetic and physiological basis of tolerance investigated. Genotypes were screened for spikelet fertility in two experiments and contrasting genotypes identified. Genotypes screened varied in the timing of early morning flowering (heat avoidance) and true heat tolerance (high spikelet fertility at high temperatures). Reproductive organ morphology and the physiological processes during anthesis were studied. None of the morphological characters contributed to heat tolerance while anther dehiscence and pollen germination were probably the most critical stages. QTLs for spikelet fertility at high temperature (heat tolerance) were identified in Azucena x Bala mapping population. Proteomic analysis identified proteins involved in heat tolerance mechanism, including a cold shock protein for the first time, indicating the possibility of protection across stresses. The physiological, proteomic studies and the genotypic screening revealed N22 to be the most tolerant genotype because of better anther dehiscence, pollen germination and significantly changing proteins enabled N22 to withstand high temperatures. Heat tolerance is highly heritable and can therefore be used in a breeding programme. The significant chromosomal regions (QTLs) and proteins (PQLs) identified will ease introgression of reliable genes to breed genotypes better adapted to future climates.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available