ECOPHYSIOLOGICAL CHARACTERIZATION OF MAIZE LINES SUBMITTED TO LOW WATER AVAILABILITY DURING FLOWERING

Abstract

The study of cultivars tolerant to water limitation is a sustainable alternative to mitigate the negative impacts of global climatic changes. This study was performed with the objective of characterizing maize lines exhibiting contrasting drought resistance at flowering stage, using gaseous exchange and chlorophyll fluorescence, under greenhouse conditions. Three maize lines were evaluated, being two tolerant (L 31.2.1.2 and L 29.1.1) and one sensitive (L2.3.2.1) to water deficit. At pre-flowering growth stage, two water treatments were imposed: without stress (WS) and with water deficit (WD). Five days after imposing the water stress the following characteristics were evaluated: photosynthesis rate (A), stomatal conductance (gs), leaf transpiration (T), intrinsic water use efficiency (iWUE, A/gs), relative chlorophyll content (SPAD) and chlorophyll fluorescence parameters (Fv/Fm; Fo/FM; Fv/Fo). The drought tolerant lines showed greater efficiency in water use, compared to the sensitive line. The line L 29.1.1 presented greater photosystem II efficiency (Fv/Fm) than lines L 2.3.2.1 and L 31.1.2.Based on the results it can be concluded that there are ecophysiological differences on gaseous exchange and chlorophyll fluorescence, which characterize the drought tolerant lines, when compared to the sensitive one. The results obtained in this research will be useful for plant breeders to select drought tolerant genotypes.

Keywords

• gaseous exchange
• Zea Mays L.
• drought
• chlorophyll fluorescence