Decorative value, yield and seed quality of the species Nigella damascena L. and Nigella sativa L. in different cultivation conditions

Suvremeni način života nameće nove trendove u industiji ukrasnog bilja što rezultira povećanom potražnjom za vrstama skromnih agroteničkih zahtjeva, otpornim na bolesti i štetnike. Crnjika (Nigella damascena L.) i crni kim (Nigella sativa L.) svojim skromnim agrotehničkim karakteristikama i višestrukom iskoristivosti predstavljaju nove potencijalne usjeve za uzgoj u ukrasne, prehrambene i ekološke svrhe. Koriste se kao ukras na cvjetnoj gredici i za rez, a tobolci za izradu suhih aranžamana. Sjeme obiju vrsta ima aromatična svojstva, te se u zemljama tradicionalnog uzgoja koristi u začinske svrhe. Posljednjih godina crni kim je u fokusu znanstvenih istraživanja zbog ljekovitog djelovanja ulja. Širenjem proizvodnje ukrasnog i ljekovitog bilja raste interes za uzgojem ovih vrsta, ali problem je nedostatak sjemena i neistraženi uvjeti uzgoja. Hrvatska ima idealne uvjete za uzgoj sjemena gotovo svih kultiviranih biljaka, te je istraživanje utjecaja uvjeta uzgoja na ukrasnu vrijednost, urod i kakvoću sjemena ovih vrsta osnovni korak koji otvara put uzgoju istraživanih vrsta u ukrasne i merkantilne svrhe. Pretpostavka ovog istraživanje je da će uvjeti uzgoja (zaštićeni prostor, otvoreno) i gnojidba dušikom imati najveći utjecaj na ukrasnu vrijednost. Na urod sjemena najveći utjecaj će imati gnojidba dušikom i fosforom, a na kakvoću sjemena uzgoj u zaštićenom prostoru (manja zaraza sjemena bolestima) i gnojidba fosforom (viša klijavost i masa 1000 sjemenki). U cilju dokazivanja navedenih pretpostavki provedeno je dvogodišnje vegetacijsko i laboratorijsko istraživanje. Na površinama Visokog gospodarskog učilišta u Križevcima postavljen je istovjetni višefaktorijelni pokus s dvije biljne vrste crnjikom i crnim kimom. Faktori u istraživanju su uvjeti uzgoja (zaštićeni prostor, otvoreno), godina (2012., 2013.) i gnojidba (kontrola, gnojeno sa 30 kg·ha-1 dušika ili 30 kg·ha-1 fosfora). Pokus je postavljen po slučajnom bloknom rasporedu u četiri ponavljanja na kolekcijskom polju i u plasteniku. Tijekom vegetacije provedena su morfometrijska mjerenja i određivanje sastavnica i uroda sjemena. Svojstva kakvoće sjemena ispitana su u laboratoriju za kontrolu kakvoće poljoprivrednog reprodukcijskog materijala Visokog gospodarskog učilišta u Križevcima prema Pravilniku o metodama uzorkovanja i ispitivanja kvalitete sjemena (NN 99/08) i International Rules for Seed Testing, Chapter 5, Germination 5-70 (ISTA, 2011). Prikupljeni podaci uneseni su u računalni program Microsoft Excel u kojem su pripremljeni za statističku obradu. Podaci su statistički obrađeni u programu SAS 9.4 (SAS, 2012). Prema rezultatima provedenog istraživanja uzgoj u zaštićenom prostoru utjecao je na ukrasnu vrijednost samo kod crnjike, čime je djelomično potvrđena pretpostavka ovog istraživanja. Uzgojem u zaštićenom prostoru kod obje vrste postignute su veće vrijednosti sastavnica uroda sjemena, što je rezultiralo i višim urodom sjemena po hektaru. Sukladno očekivanom, sjeme proizvedeno u zaštićenom prostoru imalo je manji postotak bolesti kod obje vrste. Viša vlaga, energija i klijavost sjemena crnjike postignuti su u zaštićenom prostoru, dok je kod crnog kima postignuta samo viša masa 1000 sjemenki. Kod crnjike je godina utjecala na ukrasnu vrijednost i broj sjemenki u tobolcu, ali razlike u urodu sjemena po biljci i urodu sjemena po hektaru u dvije godine uzgoja nisu postignute kod ni jedne vrste. Uzgojem u dvije godine postignute su značajne razlike u vlagi sjemena kod obje vrste. Energija i klijavost sjemena crnog kima značajno se razlikovala u dvije godine, dok je kod crnjike razlika postignuta samo u energiji klijanja, a na samu klijavost sjemena godina nije značajno utjecala. Gnojidba dušikom i fosforom imala je najveći utjecaj na ukrasnu vrijednost, urod sjemena po biljci i urod sjemena po hektaru. Utjecaj gnojidbe fosforom na masu 1000 sjemenki potvrđen je ovim istraživanjem kod obje vrste, dok na klijavost sjemena gnojidba fosforom nije utjecala. Visina uroda sjemena postignuta gnojidbom dušikom i fosforom trebala bi biti osnovna smjernica u uzgoju ovih vrsta. Neovisno o istraživanim uvjetima postignuta je visoka kakvoća sjemena kod obje vrste, što potvrđuje činjenicu da živimo u zemlji sa neograničenim mogućnostima u uzgoju sjemena.Decorative value, yield and seed quality of the species Nigella damascena L. and Nigella sativa L. in different cultivation conditions Within the last couple of years the area of horticulture is marked by a trend of introducing new flowering species in decoration of city areas and house gardens. Annual and biennial flowering species attractive for their abundant flowering, diversity of forms and colours of flowers proved to be highly sensitive to diseases and pests and very demanding in their cultivation. Their application is frequently not in accordance with the purpose of the place where they are used, which resulted in the change of landscape in both urban and rural areas. Awareness about the need to coexist with the nature led to demand for ornamental plants with modest agro-technical requirements, resistant to diseases, pests and climate changes. The species Nigella damascena L. (love in mist) and Nigella sativa L. (black cumin) for their positive agronomic characteristics and multiple usage possibilities seem to be potential crops for ornamental and organic purposes, as well as for industrial use. Nigella damascena has unusual flowers and is therefore ideal for cultivation in flower beds and for cutting, whereas the pods are used for making flower arrangements. Besides being used as ornamental plant, it is also used as spice and medicinal species because of its seed which contains oil and has intensive smell and mild and aromatic flavour. Gradual disappearance of traditional gardens caused disappearance of the species Nigella damascena which was traditionally cultivated in Croatia. Within the last decade Nigella sativa attracts increasing attention of scientists from the field of medicine and pharmacology, although medicinal effect of this plant has been known for a long time. It is considered to be one of the most healing plant species because of the chemical composition of the essential oil from its seeds. Although it is primarily used as medicinal plant in the countries where it is traditionally cultivated, it can also be used for ornamental purposes. Multiple usage makes these plant species plants of the future, especially in our country which has excellent possibilities for production of ornamental, medicinal and aromatic plants due to its favourable agroecological conditions. Agricultural producers are interested for production of new species, but they are discouraged due to lack of high quality seed material and lack of research regarding the conditions of cultivation. The first and most important step in production of any plant species is to research the possibility of producing quality seed, especially for species that were not previously cultivated in a certain climate area for commercial purposes or for seed production. This research will define agrotechnical conditions of cultivation, ornamental value, yield and quality of seed of Nigella damascena and Nigella sativa species in different cultivation conditions (protected area, open area) in two years and with three fertilization variants (control, nitrogen fertilization, phosphorus fertilization). It is estimated that the cultivation conditions and nitrogen fertilization will have the highest impact on ornamental value (plant height, number of flowering branches and pods per plants), whereas seed yield will be primarily affected by fertilization and not so much by cultivation conditions. Cultivation in protected area will result with smaller contamination of seeds with disease, whereas phosphorus fertilization will positively affect germination and 1000 seed weight. In order to prove the above stated assumptions a two year vegetation and laboratory research was carried out. On the testing grounds of Križevci College of Agriculture an identical multifactorial trial with two plant species was set up - Nigella damascena and Nigella sativa. The research included the impact of cultivation conditions (protected area, open area), years (2012, 2013) and fertilization (no fertilization, nitrogen fertilization in the amount of 30 kg·ha-1 and phosphorus fertilization in the amount of 30 kg·ha-1) on morphological characteristics, yield and seed quality of Nigella damascena and Nigella sativa. The trial was set up according to random block order in four repetitions. The sowing in the open area was administered on the collection field and in the protected area in the glass house. There were 12 test land plots in the open area and 12 in the glass house, which makes up 24 combinations, each represented with 60 plants. The size of the test surface area is 110, 5 m2, and test land plot 5 m2. Fertilization was carried out prior to sowing and incorporated into the soil using rakes. Urea was used for nitrogen fertilization and triplex for phosphorus fertilization. Test land plots were divided into two subplots of 2,5 m2, where the researched species were sown with 0,5 m distance between the species. During vegetation period in both years of research mean daily air temperature and amount of precipitation were observed. Morphometric measurements (plant height, number of flowering branches) were administered during the flowering period, and the number of pods was calculated during harvest. During seed ripening period number of seeds per pod and seed yield per plant was established. Harvest was carried out when 70 % of pods were ripe, by cutting all the pods from the test land plot. The seeds were cleaned after harvest on laboratory sieves. Seed quality was tested in the laboratory for quality control of agricultural seed of Križevci College of Agriculture. Formation of samples, testing methods for determining seed moisture, 1000 seed weight and health properties of seed were carried out in line with the Rulebook on methods of sampling and testing of seed quality OG 99/08, and testing of energy and germination capacity of seed according to International Rules for Seed Testing, Chapter 5, Germination 5 -70 (ISTA, 2011). Research data was entered in the computer programme Microsoft Excel, where it was prepared for statistical analysis in the programme SAS 9.4 (SAS, 2012). Cultivation conditions significantly influenced ornamental value of the species Nigella damascena. Cultivation in protected area resulted in higher values of plant height, number of flowering branches and number of pods per plant, whereas cultivation conditions didn't significantly affect ornamental value of Nigella sativa, which only partly confirms hypothesis of this research. Seed yield per hectare was significantly higher in protected area, resulting from a higher number of seeds in a pod and seed yield per plant for both species, which is in line with the hypothesis outlined at the beginning of this research. Laboratory research indicated smaller infection of seeds with disease for those plants cultivated in protected areas, whereas the influence of cultivation conditions on other indicators of seed quality varied depending on the species. With Nigella damascena cultivation in protected areas achieved higher moister content of seed, energy and germination capacity of seed, whereas with Nigella sativa this cultivation method affected only the 1000 seed weight indicator. Year of cultivation affected the number of flowering branches and pods per plant with the species Nigella damascena, resulting in higher ornamental value, with Nigella sativa it had no impact on any of the morphological characteristics. Although cultivation during a twoyear period resulted in a significantly different number of seeds per pod for the species Nigella damascena, year of cultivation had no impact on seed yield per plant, or seed yield per hectare for researched species. Significant impact of cultivation year was visible from results of laboratory research indicating higher seed moisture content in 2012 for both species. Cultivation year affected energy and germination capacity of seed for the species Nigella sativa, whereas with the species Nigella damascena it only affected germination energy, with no significant difference in seed germination capacity between the two cultivation years. Nitrogen fertilization had the highest impact on ornamental value for both species, which confirmed the hypothesis of this research. Besides nitrogen fertilization, the researched morphological characteristics (pant height, number of flowering branches, number of seeds per pod) were also affected by phosphorus fertilization. Fertilization with nitrogen and phosphorus resulted with the highest seed yields for both species, which can be interpreted as results of impact of fertilization on morphological characteristics and seed yield per plant. Nitrogen fertilization affected the number of seeds per pod for the species whereas with Nigella damascena fertilization had no significant impact on the number of seeds per pod. Phosphorus fertilization had a significantly higher 1000 seed weight with both species, but contrary to the expected, it did not affect germination capacity of seeds. Assumption regarding the influence of phosphorus fertilization on seed quality was therefore only partly confirmed. The species Nigella damascena and Nigella sativa belong to the genus Nigella, and due to botanical origin the assumption of this research was that both researched species will achieve the same results in researched cultivation conditions. Basic assumptions in this research were partly confirmed, but based on the laboratory research results mentioned above it is evident that the influence of the research parameters on seed quality varies between the researched species, confirming the fact that cultivation areal of a particular plant species plays a significant role in seed production. In order to produce quality seed, it is of utmost importance to research the influence of cultivation conditions on seed quality properties. this research resulted in high quality seed produced from both researched species and in all researched cultivation conditions. Research results can be used to facilitate production of high quality seed of the species Nigella damascena and Nigella sativa, which is a foundation for further cultivation of these species for ornamental purposes. Achieved seed yield for Nigella sativa should encourage agricultural producers to cultivate this species for medicinal purposes, which would lead to reduction of seed import as raw material for oil production and prevent sales of oil of suspicious quality