Harvest date modifies seed quality and oil composition of Jatropha curcas growth under subtropical conditions in Argentina

Diego F. Wassner (1) , M. Borrás (2) , Carlos Vaca Garcia (3) , Edmundo L. Ploschuk (1)

1 Facultad de Agronomía, Departamento de Producción Vegetal, Cátedra de Cultivos Industriales
2 Patagonia Bioenergía
3 CAI - Chimie Agro-Industrielle

One of the most currently promoted new crops for biodiesel productions the perennial species Jatropha curcas L. (Euphorbiaceae) due to its promising high seed yields with high oil concentrations (33–39%) and oil quality that reaching the international biodiesel standards. Although there have been different evaluations of genotypes growing under the same environmental conditions, revealing great variability for seed and oil quality, no reports are available about the effect environmental conditions during grain filling over such traits. The objectives of this work were to determine (i) the effect of harvest dates on seed quality and oil concentration, (ii) if such changes can be explained by the average temperature during grain filling and (iii) how harvest dates could affect biodiesel quality. An experiment was carried out during 29 months in experimental plots located in Formosa, Argentina. A systematic fruit harvest was conducted during 15 different dates on 10 plants with similar height (≈1.80m). Environmental conditions during the experiment were appropriate to create a broad individual seed weight range (326–752mg) and significant differences were found among harvest dates. Seed oil concentrations were significantly different among harvest dates with a maximum value of 38.7±0.6% on 08 August 2011 and a minimum of 19.6±1.8% on 17 March 2010. Oil concentration increased linearly as seed weight increased up to a value of 605mg, after which higher seed weight was not associated with greater seed oil concentration. Oil concentration was largely (r2=0.85) explained by the kernel percentage through a linear regression (y=−25.9+0.967x). Variations in seed weight and oil concentration were not associated with changes in average temperature during grain filling, suggesting that fluctuations in the source-sink relation through the growing season could explain the variations found among harvest dates. Temperature during seed filling period strongly affected oil composition and higher temperatures were associated with higher oleic acid and lower linoleic acid concentrations, although this effect generated only small effects on the biodiesel quality. Environmental conditions during grain filling modified seed quality and oil composition, while its concentration was not affected. This work reveals the existence of harvest dates effects on seed quality and oil concentration, although unrelated with the environmental conditions explored during grain filling period.

Mots clés: renewable energy; harvesting date; field experimentation; New crops; Biodiesel; Seed weight; Seed filling; Increasing temperature

Mots clés: jatropha curcas; énergie renouvelable; date de récolte; qualité germinative des graines; qualité de l'huile; argentine; expérimentation au champ

Domaines: Environnement et Société

Diego F. Wassner, M. Borrás, Carlos Vaca Garcia, Edmundo L. Ploschuk. Harvest date modifies seed quality and oil composition of Jatropha curcas growth under subtropical conditions in Argentina. Industrial Crops and Products, 2016, 94, pp.318-326. ⟨10.1016/j.indcrop.2016.09.001⟩. ⟨hal-01601402⟩