Breeding for drought tolerance in tropical maize: Conventional approaches and challenges to molecular approaches
Banziger, M.
Breeding for drought tolerance in tropical maize: Conventional approaches and challenges to molecular approaches - Mexico, DF (Mexico) CIMMYT : 2000 - Printed
Most maize in the developing world is grown under rainfed conditions and annually an estimated 24 million tons of maize are lost to drought. This paper gives a brief overview of the conventional breeding approach taken by CIMMYT in developing drought tolerant maize germplasm. Typically, progenies are evaluated in replicated trials under managed drought stress, and index selection that considers primary and secondary traits is used to identify superior germplasm. Estimates of progress of selection have been calculated. They averaged around 100 kg ha-1 year-1 of improvement. Selection gains carried over from open-pollinated varieties to hybrids and they proved td be consistent across drought environments. Improved performance under drought was largely the result of improved flowering synchronization, reduced barrenness, and an increase in harvest index; associated QTL5 have been identified. Little change in water uptake and water use efficiency was found. Challenges to molecular approaches lay in (i) identifying the genes underlying known drought- adaptive traits; (ii) exploring additional traits that confer drought tolerance; and (iii) cost-effectively deploying molecular techniques that improve the drought tolerance in adapted germplasm.
English
970-648-052-8
Aba
Cereals
Drought
Drought resistance
Injurious factors
Research projects
Plant breeding
CIMMYT
Breeding for drought tolerance in tropical maize: Conventional approaches and challenges to molecular approaches - Mexico, DF (Mexico) CIMMYT : 2000 - Printed
Most maize in the developing world is grown under rainfed conditions and annually an estimated 24 million tons of maize are lost to drought. This paper gives a brief overview of the conventional breeding approach taken by CIMMYT in developing drought tolerant maize germplasm. Typically, progenies are evaluated in replicated trials under managed drought stress, and index selection that considers primary and secondary traits is used to identify superior germplasm. Estimates of progress of selection have been calculated. They averaged around 100 kg ha-1 year-1 of improvement. Selection gains carried over from open-pollinated varieties to hybrids and they proved td be consistent across drought environments. Improved performance under drought was largely the result of improved flowering synchronization, reduced barrenness, and an increase in harvest index; associated QTL5 have been identified. Little change in water uptake and water use efficiency was found. Challenges to molecular approaches lay in (i) identifying the genes underlying known drought- adaptive traits; (ii) exploring additional traits that confer drought tolerance; and (iii) cost-effectively deploying molecular techniques that improve the drought tolerance in adapted germplasm.
English
970-648-052-8
Aba
Cereals
Drought
Drought resistance
Injurious factors
Research projects
Plant breeding
CIMMYT