D. Puangbut - Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand.
S. Jogloy - Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand.
N. Vorasoot - Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand.
C.C. Holbrook - United States Department of Agriculture-Agricultural Research Service, Coastal Plain Experiment Station, Tifton, Georgia, USA.

Seasonal variation (e.g. temperature and photoperiod) between growing seasons might affectinulin content and inulin yield of Jerusalem artichoke. However, there is limited information ongenotypic response to seasons for inulin content and inulin yield. The objective of this studywas to investigate the variability in genotypic response to seasons for inulin content and inulinyield of Jerusalem artichoke. Field experiments were conducted during the early-rainy seasonfrom June to September 2011 and the post-rainy season from September to December in 2011and these 2 seasons were repeated in 2012 at the Field Crop Research Station of Khon KaenUniversity. A randomized complete block design (RCBD) with 5 replications was used. FourJerusalem artichoke genotypes were studied during both seasons in each year. Data wererecorded for brix value, inulin content, tuber yield, inulin yield, biomass and harvest index atharvest. The results revealed that seasonal variations had significant effects on inulin content,inulin yield, tuber yield, biomass and harvest index but not on brix value. The results indicatedthat growing Jerusalem artichoke in the early-rainy season with high temperature and longphotoperiod resulted in greater inulin content and biomass. In contrast, growing Jerusalemartichoke in the post-rainy season with low temperature and short photoperiod resulted ingreater tuber yield and inulin yield. The present study revealed that temperature and photoperiodwere important for producing tuber yield and inulin yield. This information can be used to selectthe appropriate growing seasons for sustainable production of inulin content, inulin yield andtuber yield of Jerusalem artichoke in Thailand.

Sunchoke, Growing season, Temperature, Photoperiod, Tuber yield, Fructan