Variation between and within species of rapeseed (Brassica campestris and B. napus) in response to drought stress III. Physiological and physicochemical characters

Abstract

Genotypic variation in physiological and physicochemical parameters associated with drought resistance was observed between cultivars in Brassica napus and B. campestris. Significant variation in proline accumulation, chlorophyll stability, germination rate and percentage, relative turgidity, growth rates and water use efficiency were found in plants grown under simulated drought conditions in a glasshouse. No variation was detected between cultivars for leaf diffusive resistance or heat tolerance.

A yield index for each cultivar was derived from yield performances in nine different field environments. Chlorophyll stability and proline accumulation in leaf tissue and germination percentage in solution equivalent to –17.5 bars osmotic potential was clearly related to this yield index in B. napus and to a lesser extent in B. campestris. The winter cultivars of B. napus also possessed drought resistance characteristics, and they may be a valuable resource for the development of cultivars for droughted environments. Parameters were measured in a glasshouse, prior to anthesis, and therefore offer potential as ancillary selection criteria for drought resistance in oilseed rape growing in Western Australia.