Abstract only

Leaf growth and Anthesis-Silking Interval (ASI) are the main determinants of source and sink strengths of maize via their relations with light interception and yield, respectively. They depend on the abilities of leaves and silks to expand under fluctuating environmental conditions, so we raise the possibility that they may have a partly common genetic determinism. Maximum leaf elongation rate and the slopes of the responses to evaporative demand and soil water status were measured on the Phenodyn platform, in a mapping population which segregates for ASI. ASI was measured in 3 and 5 fields under well-watered and water deficit, respectively. For each RIL, the maximum elongation rate per unit thermal time was reproducible over several experiments in the absence of water deficit. It was accounted for by 5 QTLs, among which three co-localised with QTLs of ASI in well-watered conditions. The alleles conferring high leaf elongation rate conferred a high silk elongation rate. The responses of leaf elongation rate to evaporative demand and to predawn leaf water potential had 3 QTLs in common with ASI of plants under water deficit. The alleles for leaf growth maintenance were those for maintained silk elongation rate. These results may have profound consequences for modelling the genotype x environment interaction and for designing drought tolerant ideotypes

Generation Challenge Program

English

Lucia Segura

INT1991

CIMMYT Staff Publications Collection