Effect of fertilization on Guindilia trinervis in its natural habitat and in the greenhouse

Abstract

Guindilla trinervis is a wild plant that bears seeds with a high content of oil. It is relatively frequent in the mountains between the regions of Coquimbo and Maule in Chile and grows predominantly at altitudes of 1,400-2,200 m a.s.l., in the Andes as well as in the Coastal Range at lower altitudes. The quality of the oil in its seeds is suited for biodiesel but its commercial value is restricted by the marginal conditions of the natural environment and the limited available information on its physiology and agronomic performance. This study is aimed at evaluating nitrogen, phosphorous and potassium fertilization on seed yield in its natural environment and at determining nitrogen demand and absorption of nitrogen fertilization on nitrogen, phosphorous and potassium of leaves, roots and stems in the greenhouse. Adult plants under field conditions without chemical fertilization (control) and fertilized with 75-30-30 kg ha^-1 of nitrogen, phosphorous and potassium yielded 0.19 and 16.6 g m^-2 dry matter of seeds per 0.1 m², correspondingly. According to the conversions used by the authors, this production is equivalent to 2.62 and 223 L ha^-1of biodiesel in the control and the complete treatment, respectively. During the growing season sprouts of fertilized plants grew 2.9 cm in the 75-30-30 treatment and 7.6 cm in the control without fertilization. In the greenhouse nitrogen fertilization affected the biomass of leaves and stems, but did not influence root biomass. Nitrogen supply of 2 g plant^-1 increased leaf and stem weight and decreased significantly these organs with doses of 16 g plant^-1 of nitrogen. Guindilia trinervis with fertilization increased seed yield in the field and nitrogen application favored the accumulation of biomass in the greenhouse. An isolated elite plant, previously selected in the wild for productivity, yielded 445 L ha^-1 of biodiesel without fertilization; which opens the possibility for genetic improvement of this species.