GENOTYPIC VARIABILITY FOR INULIN CONTENT, TUBER YIELD AND TUBER WEIGHT OF JERUSALEM ARTICHOKE (Helianthus tuberosus L.) GERMPLASM

Inulin content is a priority trait in Jerusalem artichoke breeding program. However, breeding for high inulin in Jerusalem has not been reported in the semi-arid tropics. The objective of this study was to evaluate the genotypic variation for inulin content and to the selection of parental line for useful in breeding for high inulin content under different seasons. Development of high inulin content genotypes with high yield and good agronomic traits is required, and it can be improved through breeding. Field experiments were conducted during the late-rainy season from September to December 2014 and early -rainy season from June to September in 2015 at the Field Crop Research Station of Khon Kaen University. A randomized complete block design (RCBD) with two replications was used. Ninety-six Jerusalem artichoke accessions were used in both seasons. Data were recorded on tuber number per plant, fresh tuber yield and inulin content at harvest. The results indicated that Jerusalem artichoke accessions were significantly different for inulin content, tuber number per plant and fresh tuber yield, and there were significant genotype x environment interactions for these traits. However, the interaction between genotype and environment for these traits was low compared to genotype effect. Therefore, the genotype with high inulin content could be identified in this study. HEL 278 had consistently high inulin content and fresh tuber yield across seasons. This genotype could be used to develop high inulin content coupled with high tuber yield in the breeding program. The information on genetic variation in inulin content is useful for selection of parental lines in Jerusalem artichoke breeding program for improvement of inulin content.