Variation of inulin content, inulin yield and water use efficiency for inulin yield in Jerusalem artichoke genotypes under different water regimes

• Inulin content was increased under W2 conditions.
• Water use efficiency for inulin yield (WUEi) was increased under limited water.
• Improvement of WUEi could have contributed to higher inulin yield.
• WUEi use for selecting genotype in Jerusalem artichoke under limited water.

The information on genotypic variation for inulin content, inulin yield and water use efficiency of inulin yield (WUEi) in response to drought is limited. This study was to investigate the genetic variability in inulin content, inulin yield and WUEi of Jerusalem artichoke (Helianthus tuberosus L.) under different water regimes. A field experiment was conducted for two years during September to January 2010/2011 and 2011/2012. A strip plot design with four replications was used in both years. Horizontal factors were three irrigation levels (W1 = 100% evapotranspiration (ET), W2 = 75% ET and W3 = 45% ET) and vertical factors were 12 Jerusalem artichoke genotypes. Data were recorded for inulin content, inulin yield and WUEi at harvest. Significant differences among Jerusalem artichoke genotypes were observed for inulin content, inulin yield and WUEi under W1, W2 and W3 in both years. There were five genotypes (HEL 253, HEL 53, HEL 256, HEL 65 and CN 52867) that exhibited consistently high inulin content and inulin yield across water regimes in both years. Inulin content was increased under W2 conditions but not inulin yield, while WUEi was increased under both W2 and W3 conditions. CN 52867 and HEL 65 were the genotypes with the highest inulin content and inulin yield under limited water conditions in both years. Furthermore, these genotypes showed high WUEi and drought tolerance indices under drought conditions in both years. Improvement of inulin content combined with high WUEi could have contributed to higher inulin yield under limited water conditions. The information on genotypic variation in inulin content and WUEi under drought conditions may have application in genetic improvement of drought resistance in Jerusalem artichoke.