Influence of organic technology on vegetative growth and production of three climbing edible roses (Rosa sp.)

In the present study, three climbing edible roses (‘Crown Princess Margareta’, ‘Falstaff’ and ‘Brother Cadfael’) were evaluated for total vegetative growth and flowers production besides correlations with soil microbiological and agrochemical parameters. The applied organic technology included a soil preparatory stage with three ameliorative plants (Sinapis alba L., Phacelia tanacetifolia L. and Tagetes patula L.) and two organic mulch variants (wood chips and wool) after plantation. In variant Sinapis and Tagetes, all three varieties of roses showed the highest values for parameters: total vegetative growth, number of shoots, average shoots length and flowers number. Significant positive correlations between biometric parameters and soil bacteria, phosphorus, mineral nitrogen, potassium (0-20 cm horizon) and humus (20-40 cm horizon) content were observed. Significant positive correlations between the number of flowers and the soil respiration coefficient, soil content in phosphorus, potassium, humus, total soluble salts and mineral nitrogen were noticed. Negative correlations with soil pH have been observed. Taking into account the data obtained in the two flowering stages in 2017, the average yield per hectare cultivated with ‘Crown Princess Margareta’ was 9.44 t petals/ha. For the ‘Falstaff’ and ‘Brother Cadafael’ cultivars, the yields were 7.54 and 5.62 t petals per hectare respectively.


Introduction
Edible roses have been classified by many authors (Bojor and Răducanu, 2007;Milică et al., 2010;Stănică and Braniște, 2011;Sumedrea et al., 2014) within species of the genus Rosa such as Rosa rugosa Thunb., Rosa centifolia L., Rosa damascena Mill., of whose petals can be used for the jam production. But many breeders (David Austin in the United Kingdom, Rosen Tantau and Kordes in Germany, Meilland in France, etc.) offer a large series of rose cultivars that are not of the above species and have the word 'edible' (which can be used in food industry for jam, sweetness, syrup, etc.). Vinokur et al. (2006) and Friedman et al. (2010) defined the edible rose as the rose whose petals are not bitter or astringent and have a texture suitable for consumption, extending the notion of edible roses to thousands of cultivars. The rose has been also used since ancient times as a medicinal plant (Lambraki, 2001;Hessayon, 2005;Milică et al., 2010;Lia et al., 2014;Dong et al., 2017;Fernandes et al., 2017). Bojor and Răducanu (2010) provided details on the pharmacological properties, mentioning the rich content in tannin of petals, having anticancer, slightly laxative, aphrodisiac, decongestant, disinfectant, antiseptic, haemostatic activity. Rose syrup has been recommended in the treatment of mouth, migraine and neuralgia. Milică et al. (2010) mentioned the role of rose jam in the treatment of lung disorders and oral cavity. The use of rose both in medical and food industry was mentioned by Lambraki (2001), Vasilca-Mozăceni (2002) and Hessayon (2005) with details on the different products that can be obtained. The edible rose had great nutritional properties, being recommended by its content in carotenoids, anthocyanins, flavonic derivatives, tannins, vitamins, etheric oils etc. (Milică et al., 2010). The aim of this research, taking into account the criterion mentioned by Vinokur et al. (2006) and Friedman et al. (2010) and the possible use in medicinal or food industry, was to study the behavior of three climbing edible roses 'Crown Princess Margareta', 'Falstaff' and 'Brother Cadfael' varieties under an organic technology.

Materials and Methods
Description of the study site The research has been carried out in the Experimental Field of Faculty of Horticulture within USAMV Bucharest and in the Research Centre for Studies of Food and Agricultural Products Quality. In 2015, an organic rose culture of a total area of 1,350 m 2 with three climbing edible cultivars: 'Falstaff', 'Brother Cadfael' and 'Crown Princess Margareta' (Austin, 2012) was established and an organic technology was applied, including increasing soil biologic activity using three ameliorative species: Sinapis alba L., Phacelia tanacetifolia L. and Tagetes patula L. before and after planting. On the row, the soil was mulched with wool and wood chips and for irrigation, a drip system was used (Butcaru et al., 2017;Matei et al., 2017). The inter-row was kept grassy through repeated mowing. Different bio-stimulators, fertilizers and plant protection specific strategy were used (Butcaru et al., 2018).

Experimental design
All the three ameliorative species used (Sinapis alba L., Phacelia tanacetifolia L. and Tagetes patula L.) were sown combining the three species in seven variants: V1 Sinapis, V2 Sinapis + Phacelia, V3 Phacelia, V4 Sinapis + Tagetes, V5 Sinapis + Tagetes + Phacelia, V6 Tagetes + Phacelia, V7 Tagetes and a control parcel V8, was kept as black field, without sowing. They were trimmed and incorporated into the soil after the flowering period. Starting with 2016, on the rose rows, the soil was mulched with wool and wood chips for each initial variant (Vn): Vn.1 wood chips and Vn.2 wool, while the control Vn.3, was represented by unmulched soil. Both mulched rows had the same 1 m width with the specific material ( Figure 2). For 2017 year, after counting the flowers number in the first and second flowering stage, estimated production was made for fresh and dried petals. To estimate the flower and petals weight, 10 flowers per each cultivar were collected. They were also weight after their dehydration with a dehydrator four hours at 40 °C.

Statistical analysis
Data statistical analysis was performed with Excel (MS Office) and Quattro programs. ANOVA oneway together with T, F and Z tests were used. For correlation between two data sets Excel statistical functions with a significance level p < 0.05 were used (Pomohaci and Vâșcă -Zamfir, 2017).

Results and Discussion
Total growth length Significant differences were noticed between V1 -V8 variants for all three roses' cultivars ( Figure 3). The highest total vegetative growth was registered in V4 (Sinapis + Tagetes) and V6 (Tagetes + Phacelia) for all three cultivars while V3 (Phacelia) and V7 (Tagetes) for the lowest values. 'Crown Princess Margareta' cultivar had the highest total vegetative growth in V1, V2, V4, V5, V6 and V8 variants while the lowest in V7 and V3 variants. 'Falstaff' cultivar had the highest total vegetative growth in V6, V2, V4 and V5 variants while the lowest in V3, V7, V8 and V1 variants. 'Brother Cadfael' cultivar had the highest total vegetative growth in V4, V1 and V6 variants while the lowest in V8, V3 and V7 variants. Positive significant correlation between total vegetative growth with soil bacteria number respectively with potential phosphorus in 0-20 horizon were noticed at 'Brother Cadfael' cultivar ( Figure 4). The results were similar with Zală (2015), soil microorganism being positive correlated with plant growth.
In 20-40 cm horizon, significant positive correlations between total vegetative growth and soil potential potassium content were registered. At 'Brother Cadfael' cultivar, there were also correlations with soil potential phosphorus and humus content (  Total rose shoots number Shoots number was an important quality parameter for edible roses, being correlated with flowers number, respectively total petal production. V1 (Sinapis) and V4 (Sinapis + Tagetes) presented the highest values for all three climbing cultivars. V7 and V3 variants presented the lowest shoots number for two cultivars ( Figure 6). 'Crown Princess Margareta' cultivar had the highest shoots number in V1, V2, V4-V6 and V8 variants while the lowest in V7 and V3 variants. 'Falstaff' cultivar had no significant differences between the eight variants. 'Brother Cadfael' cultivar had the highest shoots number in V4 and V1 variants while the lowest in V8, V7 and V3 variants. Positive significant correlation between total shoots and bacteria number was noticed at 'Brother Cadfael' cultivar (R 2 = 0.65; y = 10.1x -257.26; y = total shoots number and x = soil bacteria number). Significant positive correlations between total shoots number with mineral nitrogen, phosphorus, potassium and humus content have been observed (Table 1). The results are similar with data presented by Madjar and Davidescu (2009) and Hessayon (2005).  Average shoots length At 'Crown Princess Margareta' cultivar, average shoots length was similar in all variants, varying from 29.35 ± 4.57 cm (V8) to 37.21 ± 7.93 (V5) (Figure 7). At 'Falstaff' cultivar, there was a significant difference between variants, between 26.53 ± 3.13 cm in V7 (similar with V8 and V3) and 38.89 ± 8.47 cm in V2 (similar with V1, V4, V5 and V6).
At 'Brother Cadfael' cultivar, average shoots length varied between 27.39 ± 7.92 cm in V8 (similar with V7 and V3) to 39.69 ± 7.80 cm in V5 (similar with V6, V2, V4 and V1). For all cultivars, average shoots length was bigger than values mentioned by Hoza (2000) of 15-20 cm, due to average high of plants and climbing type.
In 20-40 soil horizon, significant positive correlation was registered between averages shoots length and soil potential potassium assimilable content (Figure 8). At 'Falstaff' cultivar, positive correlation with humus content was noticed (R 2 = 0.49; y = 4.99 x + 19.94; y = average shoots length and x = humus (%) 20-40 cm).   (Table 2) showed that at 'Crown Princess Margareta' cultivar, the biggest flowers number were in V3.2 variant (1,272) and the lowest in V8.3 variant (175). Both mulched rows had a significant flowers number highest than control row, without mulch. At the wood chips mulched and at the un-mulched rows there were no significant differences between ameliorative plants variants. At the wool-mulched rows, there were noticed a significant difference between V7.2 variant with 82 flowers and all the other.
Comparing variants, the lowest flowers number was in V7 and V8 variants and the highest in V1, V5, V2 and V4. At 'Crown Princess Margareta' cultivar, on the un-mulched rows, there was a positive correlation between flowers number and soil respiration coefficient (R 2 = 0.50; y = 28.27 x -1805.5) and at 'Falstaff' cultivar, a negative one on the wood chips mulched rows (R 2 = 0.43; y = -8.22 x + 1010.2).  At 'Crown Princess Margareta' cultivar, there were significant positive correlations between flowers number and soil phosphorus content at wood chips mulched rows, with soil potassium and humus content at wood chips mulched and un-mulched rows. At 'Falstaff' cultivar, there were significant positive correlations between flowers number with total soluble salts and mineral nitrogen at wool-mulched rows and with soil potassium content at the two mulched rows. At 'Brother Cadfael' cultivar, there were negative significant correlation with soil pH at wood chips mulched rows and positive correlations with soil phosphorus content at wood chips variants, with soil potassium at the two mulched rows and with humus at wool mulched rows (Table 3).
Positive correlations with soil total soluble salts content, mineral nitrogen, phosphorus, potassium, humus confirm the importance of these elements in flower production (Madjar and Davidescu, 2009;Hessayon, 2009). 'Brother Cadfael' cultivar showed a negative correlation with soil pH in wood chips mulched variants, confirming the tolerance to soil reaction, with preference to low acid to neutral soils with pH between 5.5 and 7.2 (Milică et al., 2010). Average pH for wood chips rows was 7.45 ± 0.21.
For all three cultivars, on the wood-chips mulched and un-mulched rows, there were negative correlation between flowers number and soil pH. At 'Falstaff' cultivar positive correlations with soil total soluble salts and with soil PAl content on the wool -mulched rows were noticed. At 'Brother Cadfaell' cultivar positive correlations with soil PAl content on the wool-mulched and un-mulched rows were registered (Table 5). Other positive correlations were with soil KAl, humus content on the wood chips or woold mulched rows. Positive correlations between flowers number and soil total soluble salts, PAl, KAl, humus content confirmed their importance in flower production, similar with Hessayon (2005), Madjar and Davidescu (2009). In the second flowering stage, all three cultivars presented negative correlation with soil pH on the wood chips mulched and un-mulched rows, with averages values of 7.45 ± 0.21 respectively 7.47 ± 0.21, higher than the optimum ones for roses (pH between 5.5 and 7.2 (Milică et al., 2010).
Comparation between the two flowering stages There were significant differences between total flowers number for 'Crown Princess Margareta' cultivar, where in the second stage had fewer flowers that in the first (16,442 comparing with 22,580) and 'Falstaff' cultivar where in the second stage had more flowers (13,597 comparing with 7,511). For 'Crown Princess Margareta' cultivar, there was also a significant difference on the wood chips mulched rows, in the second stage being fewer flowers. On the wool mulched and un-mulched rows, the average total flowers number was similar between the two stages. At 'Falstaff' cultivar, total flowers number on the wood and un-mulched rows were significant higher in second stage (Vn.2: 5,702 comparing with 2,651; Vn.3: 4,234 comparing with 2,115). At 'Brother Cadfael' cultivar, total flowers number on the wool-mulched rows was significant higher in the second stage (4,676 comparing with 2,949).
Production estimation for edible organic rose orchard Average flower, fresh and dehydrated petals weights were presented in Table 6. The estimated flower and petal production for one-hectare edible rose orchards was presented in Table  7, considering 3,750 plants per hectare. Estimated production was highest than other cultivars like Rosa damascena Mill., where the average was between 2.6-5.26 t ha -1 (Chira, 2009;Samadiyan-Sarbangholi et al., 2013).

Conclusions
Climbing edible roses ('Crown Princess Margareta', 'Falstaff' and 'Brother Cadfael') cultivated with an organic technology had flowers production higher than the usual edible roses used in the actual plantations. Taking into account data obtained in the two flowering stages in 2017, the average yield per hectare cultivated with 'Crown Princess Margareta' was 9.44 t petals ha -1 , for 'Falstaff' cultivar 7.54 t petals ha -1 and for 'Brother Cadfael' 5.62 t ha -1 . The influences of ameliorative plants (Sinapis alba L., Phacelia tanacetifolia L., Tagetes patula L.) and of organic mulch (wood chips, wool) were noticed through several significant correlations bertween total vegetative growth and flowers numbers and soil microbiological and agrochemical parameters.