Growing, yielding and quality of different ecologically grown pumpkin cultivars

SCIENTIFIC WORKS OF THE LITHUANIAN INSTITUTE OF HORTICULTURE AND LITHUANIAN UNIVERSITY OF AGRICULTURE. SODININKYSTĖ IR DARŽININKYSTĖ. 2008. 27(2). Growing, yielding and quality of different ecologically grown pumpkin cultivars Rasa Karklelienė, Pranas Viškelis, Marina Rubinskienė Lithuanian Institute of Horticulture, Kauno 30, LT-54333 Babtai, Kaunas distr., Lithuania, e-mail: R.Karkleliene@lsdi.lt Investigations were carried out at the Lithuanian Institute of Horticulture in the greenhouse of ecological seed-growing covered with double polymeric film, in the natural soil in loam on loam, more deeply epihypogleyic luvisol (IDg 8-k, /Calc(ar)i Epihypogleyc Luvisols LVgp-w-cc), enriched with peat-compost substrate. There was grown Cucurbita pepo L. cultivar Beloruskaja and two cultivars of Cucurbita maxima Duch. Gele Reuzen and Bambino. Morphological indices of pumpkin fruits were fixed in three stages. It was established that the main pumpkin fruit growth took place in August. Then they already had fruits characteristic to the cultivar. In September ripening processes occurred in fruits, therefore fruit weight didn t differ strongly from the second weighting of pumpkin fruits. Investigations showed that pumpkin cultivar Gele Reuzen produced fruits, which weighted on the average from 8.0 to 8.7 kg. Pumpkins accumulate on the average 4.73 % of dry soluble solids. Cultivar Beloruskaja distinguished itself with bigger their amount. Sugar concentration in pumpkins changed from 3.1 % to 4.29 %. The least amount of sugars was established in pumpkins of cultivar Bambino, the biggest one in pumpkins of cultivar Beloruskaja. These vegetables accumulate little amount of ascorbic acid on the average 3.33 mg 100 g -1. Dependently on the cultivar, the amount of the accumulated nitrates in pumpkins change in wide limits from 105 ( Gele Reuzen ) up to 636 ( Bambino ) mg kg -1. The amount of carotenoids was investigated in the edible part of pumpkins. More of them was established in cultivar Beloruskaja (5.94 mg 100 g -1 ). Key words: chemical composition, colour parameters, cultivars, growth, yield, morphological indices, pumpkin. Introduction. Lithuanian climate is excellent for pumpkin growing. It is suitable for them rich, soft soil, which quickly gets warm. Pumpkins grow faster, when stems, which start fruits, are shortened. When growing large-fruit pumpkins, it is left on plant 3 4 started fruits (Елацкова, 2005). Fruit quality is significantly influenced by the conditions of growing, fertilization and other factors (Paulauskienė et al., 2005). When growing pumpkins, it is very important to select the suitable cultivars, which genetype influences taste properties. Pumpkins suitable for using should be completely ripen, with hard skin and, with the exception of several striped species, of uniform external colour. The flesh of the pumpkins, which are of good quality, is brightly yellow or orange with excellent juicy structure; there are much dry soluble solids, sugars (1.15 14 %), starch (1.5 20 %), pectin (4.8 12.8 %) and cellular tissue (0.7 0.95 %) in them. In the pumpkins of some cultivars there is more carotene than in carrots (up to 16 mg 100 g -1 ) (Cantwell and Suslow, 1998; Prohens, Nuez, 2007). Because of the 401

big amount of pigments, these vegetables are valuable and widely spread (Hazara et al., 2007; Kidmose et al., 2006). There are these vitamins in pumpkin fruits: vitamin C (8 mg 100 g -1 ), B1 (0.03 mg 100 g -1 ), PP (0.5 mg 100 g -1 ). It is found in pumpkin vitamin T (0.07 0.08 mg %), which improves assimilation of nutrients. Pumpkins have one of the biggest amounts of iron among vegetables. They help to assimilate food, which is hard to digest, and they have little calories (Лебедева, 1989). The flesh of overripen fruits is dryer and have more fibres. The time of pumpkin harvesting coincides with fruit physiological maturity, the features of which are observed visually. When the surface of skin loses its brilliance and becomes hard and resistant to mechanical effect, the fruit is easily to pick from the stem. When the yield is gathered too late, pumpkin fruits during storage are more injured by root diseases (Hawthorne, 1990). The aim of investigation is to select ecologically grown pumpkin cultivar, which are distinguished for good nutritional properties and are suitable to process. Object, methods and conditions. Investigations were carried out at the Lithuanian Institute of Horticulture in the greenhouse of ecological seed-growing covered with double polymeric film, in the natural soil in loam on loam, more deeply epihypogleyic luvisol (IDg 8-k, /Calc(ar)i Epihypogleyc Luvisols LVg-p-w-cc), enriched with peat-compost substrate. There was grown Cucurbita pepo L. cultivar Beloruskaja and two cultivars of Cucurbita maxima Duch. Gele Reuzen and Bambino. Pumpkins were sown in the heated nursery on May 4, 2007. Into the constant growing place in the greenhouse shoots were planted at the distances of 140 Ч 90 cm, three plants per each replication, on May 29. The area of experimental field was 3.78 m 2. Experiment was carried out in three replications. Pumpkins of technical maturity were gathered on September 20. During pumpkin growing, morphological parameters of fruits were evaluated: length, diameter, weight and the average yield. Morphological indices of pumpkin fruits were evaluated in three stages. The first pumpkin yield evaluation was on July 20 (fruit diameter 4.0 6.0 cm), other on August 20 (fruit diameter 15.0 25.0 cm) and the third one on September 20 (fruit diameter 20.0 30.0 cm). In the beginning of June, 2007 weather was a little bit cooler, and this might influence pumpkin flower formation, therefore they started flowering only in the middle of June and started fruits in the first half of July. Ecologically grown pumpkins were fertilized with natural fertilizer Biokal 01 and Biojodis (for three times). When pumpkins started forming flowers, they were fertilized with Ekoplant and after a week they were sprinkled with the solution of potassium sulfate and magnesium sulfate. At the end of July plants were for two times sprayed with biological preparation (Nimazal 0.5 % concentration solution) from pests. Pumpkins during their growth each week were sprinkled with water. It was weeded and hoed with manual implement for nine times. The quality of pumpkin cultivars Beloruskaja Gele Reuzen and Bambino of technical maturity was evaluated at the laboratory of biochemistry and technology applying chemical and physical methods of investigations. Ascorbic acid was measured 402

by titration with 2.6- dichlorphenolindophenol sodium chloride solution (Ермаков et al., 1987); dry soluble solids - by digital refractometer (ATAGO PR-32, Atago Co., Ltd., Tokyo, Japan); sugar content (inverted sugar and sucrose) by Bertrand method (AOAC, 1990); total amount of dry matter was established gravimetrically by drying fruits at the temperature of 105 C up to unchangeable mass (Manuals, 1986); the amounts of nitrates potentiometrically, with ionselective electrode (Metodiniai nurodymai, 1990). Carotenoids were extracted from fresh pumpkins by hexane, and their amount was expressed by β-carotene equivalent. The amount of carotenoids was established spectrophotometrically according to Scott (Scott, 2001). Pumpkin fruit surface colour was measured with a spectrophotometer MiniScan XE Plus (Hunter Associates Laboratory, Inc., Reston, Virginia, USA). CIEL*a*b* colour parameters were recorded as L* (lightness), a* (+ redness), and b* (+ yellowness). The chroma (C* = (a* 2 + b* 2 ) 1/2 ) and hue angle (h = arctan(b*/a*)) were also calculated (McGuiere, 1992). Data were presented as the averages of the three measurements. Colour parameters were processed with program Universal Software V. 4 10. Investigations were carried out in three replications. Averages of the data of experiments and standard deviations were calculated using MS Excel program packet. For the evaluation of data significance there was used statistical program ANOVA (Tarakanovas, Raudonius, 2003). Results. The investigated pumpkins are the varieties of common and large pumpkin. Fruits of pumpkin cultivars Beloruskaja and Bambino are oval or roundoval, and these of Gele Reuzen flat. During all the stages of harvest gathering cultivar Gele Reuzen produced the biggest fruits (Table 1). The evaluation of pumpkin cultivars fruit morphological parameters showed that in the beginning of fruit growth these parameters differ from each other only slightly. The differences of cultivar morphological parameters became clear, when the intensive fruit growth took place (from July 20 up to August 20). During this period the biggest average fruit weight produced pumpkins of cultivar Gele Reuzen (6.8 kg). Fruits of the ripen pumpkins distinguished themselves with the features characteristic to the cultivar. After evaluation of the productivity of the investigated pumpkin cultivars, it was established that pumpkin cultivar Gele Reuzen produced the biggest total yield (27.6 kg m -2 ) (Table 2). Out of the investigated pumpkin cultivars, Bambino pumpkins distinguished themselves with the smallest total yield. 403

Table 1. Evaluation of pumpkin morphological parameters 1 lentelė. Moliūgų morfologinių požymių rodikliai Babtai, 2007 Table 2. Estimation of ripen pumpkin yield 2 lentelė. Subrendusių moliūgų derliaus įvertinimas Babtai, 2007 The amount of total sugar in pumpkins was small from 3.1 up to 4.29 %. Monosaccharides dominate among sugars. The amount of sugars in pumpkins of cultivars Bambino and Gele Reuzen essentially didn t differ. Fruits of cultivar Beloruskaja had more sugars (Fig. 1). The amount of dry soluble solids in pumpkin fluctuates from 3.4 up to 5.9 %. Fruits of cultivar Beloruskaja accumulated the biggest amount of them (5.9 %) (Fig. 2). It was found only little amount of ascorbic acid in the investigated pumpkins on the average 3.33 mg 100 g -1. More of it accumulated fruits of cultivars Gele Ruzen and Beloruskaja (Fig. 2). Pumpkins of these cultivars also contain more dry matter. Essentially less amount of dry matter was established in Bambino fruits (Fig. 2). 404

Fig. 1. Sugars content of pumpkin fruits 1 pav. Cukrų kiekis moliūguose Fig. 2. Change of biochemical composition in pumpkin fruits 2 pav. Moliūgų vaisių biocheminė sudėtis There were established essential differences among cultivars according to the accumulated amount of nitrates. During the years of investigations fruits of cultivar Gele Reuzen had the least amount of nitrates (105 mg kg -1 ), more of them it was established in Bambino pumpkins (636 mg kg -1 ) (Fig. 3). Pumpkins of the analysed cultivars essentially differ from each other by the amount of accumulated carotenoids (Fig. 4). Gele Reuzen fruits have very little amount of pigments 1.7 mg 100 g -1. But Beloruskaja pumpkins accumulate 3.5 times more carotenoids and also exceed cultivar Bambino by the amount of pigments. 405

Fig. 3. Nitrates content in pumpkin fruits 3 pav. Nitratų kiekis moliūguose Fig. 4. Carotenoids content in pumpkin fruits 4 pav. Karotinoidų kiekis moliūguose Carotenoid concentration in pumpkin flesh essentially determined the parameter of their lightness index L*, which changed from 63.43 ( Beloruskaja ) up to 71.0 ( Bambino ) (Table 3). Table 3. Colour parameters in pumpkins fruits 3 lentelė. Moliūgų vaisių spalvos rodikliai The parameters of Gele Ruzen and Beloruskaja fruit flesh redness coordinate a* essentially do not differ. The flesh of Bambino has more expressed red colour and the meaning of its parameter of yellowness coordinate b* is essentially the least one (54.92). Though there are essential differences between the meanings of Gele Ruzen and Beloruskaja pumpkins coordinate b*, the meanings of yellowness of 406

the mentioned cultivars in the space of colours are similar. Gele Ruzen fruits essentially distinguished themselves with chroma (C*) (69.1). There were established essential differences among cultivars hue (h ), which is shown by the ratio between colour coordinates a* and b*. Bambino fruits have the smaller ratio of redness and yellowness and Gele Ruzen fruits the bigger one. Discussion. Pumpkin fruit external quality, size, colour depends on cultivar s genetic nature, soil, fertilization, etc. Pumpkin cultivar Beloruskaja distinguishes itself with oval or round-oval fruits, which ripe weight about 6 8 kg and the total yield per ha reaches about 50 t ha -1 (Хлебородов et al., 2005). Our investigations showed that when growing pumpkin cultivars ecologically it is possible to obtain qualitative yield. After the evaluation of morphological parameters of pumpkin fruits in different pumpkin growth stages, it was established that in the beginning of fruit growing pumpkin cultivars do not differ. During intensive fruit growing they obtain the features, characteristic to that cultivar. Ripen pumpkins distinguished themselves with the features characteristic to that cultivar and qualitative parameters of the fruit. This shows our and other investigators data (Hazara et al., 2007). Cultivar s genetype very influences pumpkin taste properties. Pumpkin flesh colour intensity depends on the amount of accumulated carotenoids, and the amounts of sugars and dry soluble solids are among fruit maturity parameters, which strongly correlate among themselves and influence pumpkin taste properties (Daniel et al., 1995; Harvey et al., 1997). Pumpkin fruits, grown as usually, ripen accumulate from 6.48 up to 20.63 mg 100 g -1 of ascorbic acid (Danilčenko et al., 2003). Pumpkins of cultivar Beloruskaja grown in 2007 distinguished themselves with the parameters of chemical composition. In the flesh of its fruits it was established the biggest amount of sugars (4.29 %), dry soluble solids (5.9 %), and carotenoids (5.94 mg 100 g -1 ). The bigger pigments concentration determined the exceptionality of the flesh colour parameters of this cultivar. Fruit flesh of cultivar Beloruskaja was of brightest orange colour. Dependently on the climate conditions and growing technologies, fruits of cultivar Bambino grown in Lithuania accumulate up to 20.63 mg 100 g -1 of ascorbic acid and 7.98 9.94 % of dry matter (Danilčenko et al., 2003). During the years of investigation the fruits of this cultivar weren t vitaminous and accumulated less dry matter. Comparing with the cultivars grown in 2007, the parameters of Bambino pumpkin chemical composition, with the exception of the accumulated amount of pigments, essentially were worse. Our data confirms the results of other investigators that there is found only a small amount of carotenoids (3.45 mg 100 g -1 ) in the flesh of the mentioned cultivar. It is necessary to mention that during the cultivars flesh colour analysis it was established the exceptionality of Bambino pumpkin colour. The parameters of coordinate a* of Bambino flesh redness in the space of colours are more in the red zone. Though there was found less carotenoids in the flesh of this cultivar in comparison with Beloruskaja fruits, we think that there may be more red b-carotene in the composition of Bambino pumpkin carotenoids. In human organism this carotene directly participate in the process of the formation of vitamin A molecules (Kidmose et al., 2006). Analysing the parameters of pumpkin cultivar colour quality it was established that the parameters of flesh colourness coordinate a*, which influenced the changes 407

of hue (h ), fluctuated more. Conclusions. 1. Pumpkins of cultivar Gele Reuzen distinguished themselves with oval form, produced on the average 8.4 kg of marketable fruits, were productive (27.6 kg m -2 ) and accumulated little amount of nitrates (105 mg kg -1 ). 2. Ripe pumpkins of cultivar Beloruskaja essentially distinguished themselves with the parameters of chemical composition. There was found in their flesh more dry soluble solids (5.9 %), sugars (4.29 %), ascorbic acid (4 mg 100 g -1 ), and carotenoids (5.94 mg 100 g -1 ). The amount of the accumulated nitrates (341 mg kg -1 ) was less than the average one (361 mg kg -1 ). 3. Out of the colour parameters, the parameters of flesh colourness coordinate a*, which influenced the changes of hue (h ), fluctuated more. References Gauta 2008 04 17 Parengta spausdinti 2008 05 05 1. AOAC. 1990. Sucrose in fruits and fruit products. In Helrich K. (eds.), Official Methods of Analysis. 15 th end, AOAC Inc., Arlington. VA, 922. 2. Cantwell M, Suslow T. V. 1998. Pumpkins and Winter squashes. Recommendations for maintaining postharvest quality. Perishables Handling Quarterly, 94: 15-16. 3. Daniel A. L. 1995. Tropical pumpkin cultigen postharvest quality evaluation and maturity studies. M. Sc. Thesis. Univ. of Florida, Gainesville FL. 4. Danilčenko H., Paulauskienė A., Jarienė E., Kučinskas J. 2003. Augimo būdų įtaka moliūgų kokybei. Sosininkystė ir daržininkystė, 22(2): 141 149. 5. Harvey W. J., Grant D. G., Lammerink J. P. 1997. Physical and sensory changes during development and storage of Buttercup squash. NZ J. Crop Hort. Sci., 25: 341-351. 6. Hawthorne B. T. 1990. Age of fruit at harvest influences incidence of fungal storage rots on fruit of Cucurbita maxima D. hybrid Delica. New Zealand J. Crop Hort. Sci., 18: 141-145. 7. Hazara P., Mandal A. K., Dutta A. K., Sikadar D., Pandit M. K. 2007. Breeding Pumpkin (Cucurbita Moschata Duch. Ex Poir.) For high Yield and Carotene content. Acta Horticulturae, 752: 431 435. 8. Kidmose U., Yang R.-Y., Thilsted S. H., Christensen L. P., Brandt K. 2006. Content of carotenoids in commonly consumed Asian vegetables and stability and extractability during frying. Journal of Food Composition and Analysis, 19: 562 571. 9. Manuals of food quality control. 1986. Food analysis: general techniques, additives, contaminants, and composition. Rome, FAO. 10. McGuiere R. G. 1992. Reporting of objective colour measurements. HortScience, 27(12): 1 254-1 255. 11. Metodiniai nurodymai nitratams nustatyti augalininkystės produkcijoje. 1990. Vilnius. 408

12. Paulauskienė A., Danilčenko H., Rutkovienė V., Kuraitienė J. 2005. The influence of various fertilizers on elektrochemical properties of pumkin fruits. Sщвштштлныеė ir daržininkystė, 24(3): 78 86. 13. Prohens J., Nuez F. 2007. Pumpkin and Winter Squash. Handbook of Plant Breeding. Vegetables I. Asteraceae, Brassicaceae, Chenopodicaceae, and Cucurbitaceae, Springer. 14. Scott K. J. 2001. Detection and measurement of carotenoids by UV/VIS spectrophotometry. In: John Wiley and Sons (eds.), Current Protocols in Food Analytical Chemistry. Inc., F.2.2.1-F.2.2.10. 15. Tarakanovas P., Raudonius S. Agronominių tyrimų duomenų statistinė analizė taikant kompiuterines programas ANOVA. STAT. SPLIT-PLOT iš paketo SELEKCIJA IR IRRISTAT. Akademija, 2003. 56. 16. Елацкова А. Г. 2005. Возможности расширения ассортимента овощной тыквы. Материалы докладов, сообщений. ВНИИССОК, Москва, 1: 212 214. 17. Ермаков А. И., Арасимович В. В., Ярош Н. П., Перуанский Ю. В., Луковникова Г. А., Иконникова М. И. 1987. Методы биохимического исследования растений, Ленинград, ВО Агропромиздат. 18. Лебедева А. Т. 1989.Тыква, кабачок, патиссон. Москва. BO Агропромиздат. 19. Хлебородов А. Я., Яковицкая Р. С., Крышко А. Н., Чернин А. Г. 2005. Направление и результаты селекции сортов и гетерозных гибридов тыквенных культур в Беларуси. Материалы международной научной конференции, Минск, 161 163. SODININKYSTĖ IR DARŽININKYSTĖ. MOKSLO DARBAI. 2008. 27(2). Skirtingų ekologiškai auginamų moliūgų veislių augimas, derėjimas ir kokybė R. Karklelienė, P. Viškelis, M. Rubinskienė Santrauka Tyrimai vykdyti Lietuvos sodininkystės ir daržininkystės instituto ekologinės sėklininkystės dviguba polimerine plėvele dengtame šiltnamyje, natūraliame dirvožemyje limnoglacialiniame priemolyje ant moreninio priemolio, giliau glėjiškame išplautžemyje (IDg 8-k, /Calc(ar) i Epihypogleyc Luvisols LVg-p-w-cc), papildytame durpių-komposto substratu. Auginta paprastojo moliūgo (Cucurbita pepo L.) veislė Beloruskaja ir didžiojo moliūgo (Cucurbita maxima Duch.) dvi veislės Gele Reuzen ir Bambino. Moliūgų vaisių morfologiniai rodikliai tirti trimis etapais. Pagrindinis moliūgų vaisių augimas buvo rugpjūčio mėnesį, kai jie jau buvo suformavę veislei būdingus vaisius. Rugsėjo mėnesį vaisiuose vyko brendimo procesai, todėl vaisių svoris nedaug skyrėsi nuo antrojo moliūgų vaisių svėrimo. Tyrimai parodė, kad Gele Reuzen veislės moliūgai suformuoja vidutiniškai nuo 8,0 iki 8,7 kg vaisius. Moliūgai sukaupia vidutiniškai 4,73 % tirpių sausųjų medžiagų. Didesniu jų kiekiu išsiskyrė Beloruskaja veislė. Cukrų koncentracija moliūguose kito nuo 3,1 % iki 4,29 %. Mažiausiai 409

cukrų nustatyta Bambino, daugiausiai Beloruskaja veislės moliūguose. Šios daržovės sukaupia mažа askorbo rūgšties kiekį vidutiniškai 3,33 mg 100 g -1. priklausomai nuo veislės, sukauptų nitratų kiekiai moliūguose kinta plačiose ribose nuo 105 ( Gele Reuzen ) iki 636 ( Bambino ) mg kg -1. Karotinoidų kiekis buvo tiriamas valgomoje moliūgų dalyje. Daugiau jų nustatyta Beloruskaja (5,94 mg 100 g -1 ) veislėje. Reikšminiai žodžiai: augimas, cheminė sudėtis, derlius, moliūgai, morfologiniai rodikliai, spalvos parametrai, veislės. 410