Phenodyn: a phenotyping plateform and an information system to dissect the genetic variability for growth and transpiration rates in response to water deficit
Résumé
Tolerance to water deficit is identified at early stages of the vegetative cycle of monocot species, especially maize. This is based on a genetic analysis of the responses to water deficit of organ growth and gas exchanges. The rationale is that (i) genotypes which do not maintain gas exchanges and leaf growth during water deficit cannot perform well in dry fields, (ii) the expansive growth of several organs (e.g. leaves and silks) have common genetic determinisms. Phenodyn imposes common fluctuating climatic and soil moisture conditions to 420 plants in greenhouse and growth chamber. Temperature, evaporative demand and soil water content are measured every 15 min, together with leaf (or silk) elongation rate and plant transpiration. Outputs are managed in a database for real time monitoring of experiments and for post-analyses of thousands of diurnal time courses of growth rate or transpiration (Sadok et al. (2007) PCE, 30: 135-146). It was used for analyzing mapping populations, a panel of lines for association genetics or insertion lines. It has also been tested for rice. The identification of early QTLs of response can be combined with models which predict leaf area, light interception and, potentially, yield. In addition to genetic analyses of physiological processes associated with plant adaptation, this platform might be a potent tool in the breeding for drought tolerance