Influence of water deficit and canopy senescence pattern on Helianthus annuus (L.) root functionality during the grain-filling phase.

Highlights: [•] We compared root functionality, during grain-filling, under control and drought conditions of stay green (SG) and fast-dry-down (FDD) sunflower hybrids. [•] The SG hybrid root system senesced slower than that of the FDD hybrid, under both irrigation and drought. [•] Root functionality determined with minirhizotron imaging showed good agreement with capacity for triphenyl tetrazolium chloride reduction. [•] Crop transpiration was greater in the SG than FDD hybrid during most of grain-filling phase, under both irrigation and drought. [•] Root senescence preceded canopy senescence in both hybrids and levels of water supply. [Copyright &y& Elsevier]