Chlorophyll fluorescence analysis of photosynthetic performance in seven maize inbred lines under water-limited conditions

Background and Purpose: Photosynthetic efficiency in crops can be associated with stress resistance and yield increase. In maize, photosynthetic efficiency is important in inbred lines during breeding process and in seed production, as well as in hybrids. Objective of this study is to determine differences in photosynthetic efficiency under the water-limited conditions between seven flint and dent maize inbred lines belonging to various heterotic groups. Moreover, this investigation will serve as a preliminary study for the QTL analysis of chlorophyll fluorescence parameters in order to understand the genetic and physiological background to drought stress tolerance in maize. Materials and Method: Photosynthetic efficiency was measured in maize field nursery in Osijek during silking by Hansatech Handy-PEA analyzer in the elite inbreds Os1767/99, Os1252/99, Os163_9, B73, Mo17, Os6_2 i B84. The data obtained were used to calculate two biophysical parameters that describe the photochemistry of PSII: maximum quantum yield of photosystem II (Fv/Fm) and performance index on absorption basis (PIABS). Obtained data were subjected to statistical analysis applying least significant difference (LSD) and cluster analysis. Results and Conclusions: Differences in photosynthetic efficiency appeared to be higher within dent inbred lines than between dents and flints. Although investigated parameters of chlorophyll fluorescence (Fv/Fm and PIABS) revealed similar clustering of inbred lines, there was slight difference concerning the grouping of the line Os6_2. Therefore we recommend the combined use of these two main parameters of chlorophyll fluorescence when the investigation includes photosynthetic performance in stress challenged plants, such as water-limited conditions.