The Roles of Net Photosynthetic Rate and Transpiration Efficiency on Economic Yield of Jerusalem artichoke (Helianthus tuberosus L.) Genotypes under Different Drought Durations during the Terminal Growth Stages

Abstract

Knowledge of the influence of different drought durations during the terminal growth stages on net photosynthetic rate (Pn), transpiration rate (Tr), transpiration efficiency (TE), and tuber fresh weight (economic yield) is relatively limited in Jerusalem artichoke. Our aim was to examine the effect of different drought durations during the terminal growth stages on Pn, Tr, TE, and economic yield in Jerusalem artichoke genotypes with different ranges of drought tolerance. A two-year field experiment was established in the northeast of Thailand. A split-plot design replicated four times was used. Three water treatments, optimal conditions (SD0), short-drought (SD1), and long-drought (SD2) durations during the terminal growth stages, were arranged as main plots. Six genotypes (HEL256, JA37, HEL253, JA4, JA60, and JA125) are subplots. Different durations of drought in SD1 and SD2 reduced Pn, Tr, and economic yield, while drought stress during the terminal growth stages increased TE in whole genotypes over SD0 treatments. Drought-tolerant genotypes JA125 and JA4 exhibited high Pn, medium TE, and low economic yield reduction under SD2. Utilization of these superior parents in breeding could lead to the generation of new progenies with high economic yield productivity and drought tolerance during the long drought duration during the terminal growth stage. In addition, high SPAD chlorophyll meter readings (SCMR) in SD1 and SD2 and low specific leaf area (SLA) in SD1 could be used as indirect selection traits to survey high Pn genotypes in Jerusalem artichoke. Consequently, these indirect selection traits may allow for speedy breeding programs in Jerusalem artichokes.