Evaluation of Yield, Yield Components and Nitrate in Some Spinach Landraces in Isfahan Province

Spinach (Spinaciaoleracea L.) is considered as a green leaf with fresh and canned consumption, a significant source for vitamin C, vitamin A, carotenoids, flavonoids, folic acid, calcium and magnesium.According to statistics, 4479 hectares of Iran agricultural land were devoted to spinachand the average yield per hectare is equal to 42.18(FAO, 2014).Different regions of Iran havegenetic diversity of the spinach landraceand cultivation of this plant relieson the use of the landraces.Among the different spinach landraces, a landracescalled seed barbed (Spiny), has a significantimportancebecause of some desirable characteristics.Thisstudy was conductedfor comparison of five spinach landracein Isfahan, showedthat spiny seed Varamin with 47.8 tons per hectare fresh yield allocated the highest yield.The number and size of leaves and side branches are the most important components of plant yield.Due to the fact that about 70 percent of total dietary nitrate intake per person per day will be provided through the leafy vegetables,considering the amount of accumulated nitrate in spinach is very important.To evaluate the yield and yield components of eight Iranian spinachlandrace, and two varieties of leafy American and German experiment was conducted for two years.
This research was performedfor two years, in Kabootarabad Agricultural Research Station of Isfahan to evaluate the yield and yield components of eight Iranian spinachlandraces(Varamin prickly seed, Sari, Ghaemshahr, Babul, Kashan, Najaf Abad, Varamin 88 andArdestān), and two American and German leafy cultivars. Randomized complete block design with three replications was usedfor each year and the results were reported based on two-year combined data analysis. In full leaf development stage and before the harvest of each plot, 10 plants randomly were selected and measured attributes: number of leaves, leaf length, leaf width and length of the petiole. In order to assess yield, after removing two distance of half a meter from each side, two central rows of plants per plot (surface equivalent to two square meters) were analyzed. Nitrate content of samples wasanalyzed using ion analyzer. Data statistical analysiswas performed using SAS software and means were compared by Duncan’s multiple rangetest at 5% probability level.
Result and Yield, leaf length, petiole length and height (at 1% statistical probability level) and number of leaves and nitrate content (at 5% statistical probability level) were statistically significant. Spiny seed Varamin with 53.49 t ha-1 fresh yield, produced to the highest yield. In other research according to the environmental conditions and variety, spinach fresh yield have been reported from 18.6 to 44.8 t ha-1. It looks different mass spinach; produce the highest yield in specific geographic environments. In a similar study that was conducted underIsfahan weather conditions, spiny seed Varaminlandraceproduced 47 830 kg ha-1 fresh yield. Range in plant height was from 24 cm to 30.33 cm in Najaf Abad, and Sari landraces, respectively. When spinach was encountered with optimal climate conditions, achieved the maximum height that led toa positive impact on fresh yield. Ardestānlandrace produced the lowest number of leaves (10.67)among the landraces/varieties had been studied. In a similar study of 29 spinach genotypes the leaf number were varied from 12 to 23. Petiole length range between varieties/landraces was from 9.84 to 18.33 cm. Although the petiole length, is a desired trait for mechanized harvesting, but in case of improper management of nitrogen fertilizer can be considered as an undesirable trait. Leafy Varaminlandracewith 231 and 462 ppm nitrate in blade and petiole, respectively, had the lowest and German cultivar with 583 and 1182 ppm nitrate in blade and petiole, respectively, had the highest nitrate accumulation. Despite the differences between the varieties/landraces,the contentof nitrate in petioles was greater than the leaf blade (about 1.6 times) in spinach. Higher concentrations of petiole nitrate compared to the blade considered in many research, and in caseof poor management fornitrogen fertilizers, it may increase up to6 times. In any case, leafy cultivars such as German have been modified for mechanized cultivation and have long petiole with nitrate content. That's why their petioles are separated in the industrialprocessing. It is better fresh petioles of spinach isolated or sufficiently boiled to reduce nitrate levels. According to the results obtained in this study among the examined populations of spiny seed Varaminlandraces, leafy Varamin, Najaf Abad, and Sari can produce yields similar toGerman variety and so are suitable for the production of spinach in Isfahan province.