The responses for inulin content and inulin yield of Jerusalem artichoke (Helianthus tuberosus L.) genotypes and the associations of net photosynthethic rate withi inulin traits to different terminal drought durations

Authors: CHAIMALA, AUNCHANA - Khon Kaen University; JOGLOY, SANUN - Khon Kaen University; VORASOOT, NIMITR - Khon Kaen University; Holbrook, Carl - Corley; KVIEN, CRAIG - University Of Georgia

Submitted to: South African Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2022
Publication Date: 10/13/2022
Citation: Chaimala, A., Jogloy, S., Vorasoot, N., Holbrook Jr, C.C., Kvien, C.K. 2022. The responses for inulin content and inulin yield of Jerusalem artichoke (Helianthus tuberosus L.) genotypes and the associations of net photosynthethic rate withi inulin traits to different terminal drought durations in the late-rainy season. South African Journal of Botany. 151:277-287. https://doi.org/10.1016/j.sajb.2022.09.047.
DOI: https://doi.org/10.1016/j.sajb.2022.09.047

Interpretive Summary: Jerusalem artichoke (JA) is a good source of inulin. Inulin is classified as a non-digestible carbohydrate and is mainly used as a food supplement for patients with obesity, type 2 diabetes, constipation, and heart disease. It also may possess anti-cancer and immune-enhancing properties. This study aimed to investigate the effect of different durations of terminal drought on inulin content and inulin yield of six JA genotypes. The associations between inulin productions with SPAD chlorophyll meter reading (SCMR) was also investigated. In all genotypes, the inulin content in tubers was significantly increased under drought in comparison with irrigated conditions. In contrast, inulin yield was drastically decreased under the drought treatments for both years. Drought tolerant genotypes were identified. These genotypes could be used as parental lines in breeding programs under terminal drought-prone areas. Positive correlations were observed between SCMR and inulin content under drought conditions. SCMR is simple to measure and could be used as a surrogate trait to select drought tolerant genotypes with high inulin content under short terminal drought conditions.

Technical Abstract: Terminal drought might increase or decrease inulin content and inulin yield of Jerusalem artichoke (JA). This study aimed to investigate the effect of different durations of terminal drought on inulin content and inulin yield of six JA genotypes. The associations between inulin productions with net photosynthesis rate (Pn) and SPAD chlorophyll meter reading (SCMR) was also investigated. The field experiment was designed as a split-plot design with four replications during the late-rainy season in 2017/18 and 2018/19. The main plots were three irrigation treatments that involved non-drought conditions (SD0), drought starting 45 (SD2), and 60 (SD1) days after transplanting (DAT) until harvest. Six genotypes (HEL 256, JA 37, HEL 253, JA 4, JA 60, and JA 125) were arranged in subplots. In all genotypes, the inulin content in tubers was significantly increased under SD1 and SD2 in comparison with SD0. In contrast, inulin yield was drastically decreased under the drought treatments for both years. HEL 256, JA 37, JA 60, and JA 125 had high inulin content and Pn under SD0, and they also had high inulin content and SCMR under SD1. JA 37, JA 4, JA 60, and JA 125 had a high inulin yield and Pn under SD2. These genotypes could be used as parental lines in breeding programs under terminal drought-prone areas. Positive correlations were observed between Pn and inulin content under SD0, Pn and inulin yield under SD2, and SCMR and inulin content under SD1. SCMR is simple to measure and could be used as a surrogate trait to select drought tolerant genotypes with high inulin content under short terminal drought conditions.