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Physiology of flowering in maize: Identifying avenues to improve kernel set during drought

By: Westgate, M.E | Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Mexico DF (Mexico).
Contributor(s): Edmeades, G.O.|Banziger, M.|Mickelson, H.R.|Pena-Valdivia, C.B [eds.].
Material type: materialTypeLabelBookAnalytics: Show analyticsPublisher: Mexico, DF (Mexico) CIMMYT : 1997ISBN: 968-6923-93-4.Subject(s): Drought stress AGROVOC | Flowering | Plant developmental stages | Plant physiology | Selection | CIMMYT | Zea mays AGROVOC | Genotypes AGROVOC | Plant breeding AGROVOCDDC classification: 633.153 Summary: Asynchronous floral development and abortion of fertilized ovaries are responsible for much of the kernel loss caused by drought during flowering in maize. Inhibition of silk elongation and ear growth at low water potential both contribute to the failure of silks to emerge during pollen shed. Because this delay in silk emergence, rather than loss of pollen availability, pollen viability, or silk receptivity generally limits kernel set, selection for genotypes which exsert silks in advance of pollen shed (protogyny) should be beneficial. Modern maize genotypes tolerate up to 6 days of protogyny without loss of silk receptivity. Rapid and sustained ovary growth also is essential to maintain kernel set during drought. A decrease in assimilate production in droughty plants coupled with inhibition of carbohydrate metabolism within the ovaries leads to a dramatic decrease in carbohydrate partitioning to the ear, and ultimately, kernel abortion. While it has been possible to reverse the effect of drought on kernel abortion by supplying sucrose via stem infusion, attempts to increase kernel set in droughty plants by increasing assimilate supply per kernel naturally under field conditions have not proven successful. The ear of maize competes poorly for available assimilates. Selection for genotypes with rapid ear growth relative to vegetative growth at anthesis is a practical method to improve ear sink strength. Current research on the molecular basis for inhibition of ovary carbohydrate metabolism and the role of cytokinins in controlling ovary growth may provide new molecular targets for improving drought tolerance in maize.Collection: CIMMYT Publications Collection
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Conference proceedings CIMMYT Knowledge Center: John Woolston Library

Lic. Jose Juan Caballero Flores

 

CIMMYT Publications Collection 633.153 EDM (Browse shelf) 1 Available 1C624179
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Asynchronous floral development and abortion of fertilized ovaries are responsible for much of the kernel loss caused by drought during flowering in maize. Inhibition of silk elongation and ear growth at low water potential both contribute to the failure of silks to emerge during pollen shed. Because this delay in silk emergence, rather than loss of pollen availability, pollen viability, or silk receptivity generally limits kernel set, selection for genotypes which exsert silks in advance of pollen shed (protogyny) should be beneficial. Modern maize genotypes tolerate up to 6 days of protogyny without loss of silk receptivity. Rapid and sustained ovary growth also is essential to maintain kernel set during drought. A decrease in assimilate production in droughty plants coupled with inhibition of carbohydrate metabolism within the ovaries leads to a dramatic decrease in carbohydrate partitioning to the ear, and ultimately, kernel abortion. While it has been possible to reverse the effect of drought on kernel abortion by supplying sucrose via stem infusion, attempts to increase kernel set in droughty plants by increasing assimilate supply per kernel naturally under field conditions have not proven successful. The ear of maize competes poorly for available assimilates. Selection for genotypes with rapid ear growth relative to vegetative growth at anthesis is a practical method to improve ear sink strength. Current research on the molecular basis for inhibition of ovary carbohydrate metabolism and the role of cytokinins in controlling ovary growth may provide new molecular targets for improving drought tolerance in maize.

English

9801|AGRIS 9702

Jose Juan Caballero

CIMMYT Publications Collection

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Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT) © Copyright 2015. Carretera México-Veracruz. Km. 45, El Batán, Texcoco, México, C.P. 56237.
Si tiene cualquier pregunta, contáctenos a CIMMYT-Knowledge-Center@cgiar.org