Nutritive Constituents of Onion Grown from Sets as Affected by Water Supply

Abstract

<jats:p>A 3-year experiment was conducted in central Hungary comparing the effect of an irrigation treatment on content and yield of dry matter, storage carbohydrates, vitamin C, total flavonols, and total polyphenols of onion (<jats:italic>Allium cepa</jats:italic> L.) grown from sets. Rain-fed plots were set as controls. Conditions during the first 40 days of the growing season had a decisive effect on yield and bulb size; warmer and dryer weather during this period resulted in lower yield. Colder and wetter weather conditions resulted in higher bulb yield, but also decreased accumulation of secondary metabolites. Dry matter content values ranged between 12% and 14% and were not influenced by the water supply. Storage carbohydrate-to-dry matter ratio was not changed by the water supply. Total flavonol contents (sum of the concentrations of nine individual flavonols) varied between 430 and 753 mg·kg<jats:sup>−1</jats:sup> on a fresh weight basis. Total polyphenol values ranged between 607 and 1029 mg·kg<jats:sup>−1</jats:sup> on a fresh weight basis. A statistically significant correlation was found between flavonol content and polyphenol content for the rain-fed treatment, but this was not the case for the irrigation treatment. Irrigation significantly increased total flavonol and total polyphenol concentrations during the dry years. Irrigation significantly increased the bulb yield by 33% to 160%, depending on the year. Consequently, by applying irrigation, yields of nutritive compounds became 1.5 to two times higher.</jats:p>

Assessment of a New Approach for Systematic Subsurface Drip Irrigation Management

“…Comparing evaporation from surface and subsurface drip irrigation systems, Evett et al [7] reported that 51 and 81 mm were saved with drip laterals buried at 15 cm and 30 cm, respectively. Patel and Rajput [8] recorded maximum onion yield (25.7 t ha −1 ) with drip laterals buried at 10 cm, whereas Ombódi et al [9] recorded an average yield ranging between 40.7 and 54.6 t ha −1 for onion in irrigated conditions. Also, with SDI systems more uniform moisture distribution, in the vadose zone (than with drip irrigation systems), was observed, and thus drainage and surface evaporation were less with SDI [10,11].…”

Water Supply and Temperature Effects on Some Nutritive Constituents of Direct Sown Onion

“…The analyses of total polyphenols were performed according to the Folin-Denis method, spectrophotometrically at 760 nm, using catechin as standard (AOAC, 1990). Flavonol detection was carried out by an HPLC method described by Ombódi et al (2013). Ash content was measured gravimetrically.…”

“…Besides affecting the growth of bulbs, temperature also affects nutritional values, flavour intensity, dry matter and sugar content of the bulb (Lee and Suh, 2009). Although onions can tolerate periods of draughts, yield is heavily influenced by draught stress (Brewster, 2008;Ombódi et al, 2013). Based on published results, it is unquestionable that under dry conditions appropriate irrigation increases onion yield to a great extent (Enciso et al, 2009;Pejic et al, 2011;Leskovar et al, 2012;Ombódi et al, 2013).…”

“…Although onions can tolerate periods of draughts, yield is heavily influenced by draught stress (Brewster, 2008;Ombódi et al, 2013). Based on published results, it is unquestionable that under dry conditions appropriate irrigation increases onion yield to a great extent (Enciso et al, 2009;Pejic et al, 2011;Leskovar et al, 2012;Ombódi et al, 2013). However, negative effects of irrigation on nutritional values, dry matter content and storage life often remains a concern for growers producing onions for quality markets (Pérez-Ortolá and Knox, 2015).…”

Híbridos de Cebolla Roja (Allium cepa L.) Propagados por Bulbillos con Diferentes Diámetros Ecuatoriales, en Zona Árida

“…La fisiología de la cebolla (Khokhar, 2017) es afectada por el ambiente y el genotipo, como el fotoperiodo que juega un rol crítico en el d e s a r r o l l o d e l b u l b o y d e t e r m i n a e l comportamiento de un cultivar para una región dada, y el bulbeo es regulado más por la temperatura, grados día y luz rojo lejano que por el fotoperiodo; el tamaño de bulbo es menor a mayor densidad de plantación; el estrés por agua durante la formación y crecimiento del bulbo es más dañino que durante el crecimiento del follaje; el nitrógeno favorece el crecimiento del bulbo, pero también el exceso promueve le enviciamiento y alargamiento del periodo vegetativo; las giberelinas y el ethrel promueven el crecimiento y desarrollo de los bulbos; la floración y la formación del bulbo es regulado por los genes FT (locus T de floración), los genes antagonistas parecidos a los genes FT regulan la formación del bulbo (Khokhar, 2017). En la producción de cebollas por bulbillos es muy importante mantener condiciones ambientales favorables tanto en la etapa inicial como en la media del cultivo, para un buen contenido de metabolitos secundarios, y que las condiciones húmedas y frías favorecen el rendimiento, pero no los metabolitos (Ombódi et al, 2013). Los bulbillos también pueden ser utilizados para la producción de semilla botánica, por costos más bajos que el sistema tradicional, siendo los bulbillos de 26 a 31 mm de diámetro almacenados por 30 días a 7°C los de mayor -1 rendimiento de semilla botánica (595 kg ha ) para el cultivar INIA Valenciana (Peluffo et al, 2016).…”