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Title: Tuber and inulin production of Jerusalem artichoke (Helianthus tuberosus, L.) under salinity stress

item Ferreira, Jorge
item DIAS, NILDO - Federal Rural University Of The Semi-Arid
item Liu, Xuan
item Suarez, Donald

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/7/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Salinization of soils and irrigation waters has increased soil salinity worldwide, and threaten to reduce crop yield. In the semiarid regions, fresh water scarcity demands salt- and drought-tolerant crops. Jerusalem artichoke (cv. Stampede), a North American crop with inulin-rich tubers, is a carbon source for biofuels and for pre-biotic, low-calorie, soluble fiber (nutraceutical value). Although previous workers studied the effect of salinity on tuber yield, only one evaluated salinity effect on inulin yield, and none on its degree of polymerization (DP). Plants were grown in 9m3 outdoor sand tanks for four months being submitted to salinity 30 days after planting. Salinity (as water electrical conductivity, ECw) increase from ECw=1.2 to 12 dS/m reduced shoot and tuber biomass by 67% and 49%, respectively, while ECw=6.6 dS/m reduced shoot biomass by 37.5%, but tuber biomass only by 13% indicating that ‘Stampede’ tolerates moderate salinity with minor tuber yield loss. Inulin tuber dry weight concentration (50-60%) and its DP were unaffected by salinity, even at ECw =12 dS/m. Based on elemental analyses, and despite increasing salinity, Na+ accumulated only in roots and tubers, but not in leaves or stems, while Cl- increased in all organs, mainly roots and leaves. As nutrient levels remained constant in shoots and roots, we propose that Cl-, not Na+, was the most toxic ion for this crop. The early-flowering ‘Stampede’ completed its production cycle in four months, suggesting its adaptability to areas with short summers and with moderate saline waters or soils. At ECw=6.6 dS/m ‘Stampede’ produced (with 2.2 plants/m2) 1.4kg tuber/plant (15.5 tons inulin/ha), being a highly attractive source of inulin for biofuels or for the functional food market. Its moderate tolerance to salinity keeps it from competing with lands used to produce conventional agricultural crops.