Sci. Agri. 5 (2), 2014: 67-72 © PSCI Publications

Scientia Agriculturae www.pscipub.com/SA E-ISSN: 2310-953X / P-ISSN: 2311-0228

DOI: 10.15192/PSCP.SA.2014.1.2.6772

Feasibility Sweet potato (Ipomoea batatas L.) growing in southern regions of Iran (Minab) climate Naseri Mohammad1, Shamili Mansooreh2*, Hamden Hassanzadeh Khankahdani3 and Elham Naseri4 1. M.Sc in Horticulture, Jahad-Agricultural Organization, Hormozgan, Iran 2. Asisitant Professor, Hormozgan University, Iran 3. Researcher, Agricultural Research station of Minab, Hormozgan, Iran 4. Graduate of Horticulture Sciences, Hormozgan University, Iran * Corresponding Author email: [email protected] Paper Information Received: 5 January 2014 Accepted: 7 February 2014 Published: 20 February 2014

ABSTRACT Sweet potato (Ipomoea batatas L.) is the seventh important food crop in the world after Wheat, Rice, Maize, Potato, Barley and Cassava, and in viewpoint of nutrition value has more protein than other tuberous crops such as cassava and Yam. In order to investigate the feasibility and finding the best planting date of Sweet potato in Minab region (Hormozgan, Iran) an experiment was conducted as factorial arrangement in randomized complete block design with two factors: planting date (23rd of August, 6th of September and 21st of September) and Cultivar (white and red) with four replications. Characteristics like plant length, leaf number, lateral stem number, the time of storage root formation were measured. Also, the characteristics of storage root (such as number; length, diameter, fresh weight; dry matter and yield) were determined after harvesting. The highest yield was observed on 23rd of August (25.36 ton ha-1) and the lowest on 21st of September (10.94 ton ha-1). The yield of white cultivar was 10.5% more than red cultivar but had no significant difference together. The greatest yield obtained in red cultivar on 23rd of August (28.12 ton ha-1) and the lowest in red cultivar on 21 st of September (9.79 ton ha-1). The highest cutting establishment percentage was related to white cultivar on 21st of September and the least in white cultivar on 6 th of September red cultivar was better than white cultivar and on two other planting dates white cultivar was better than red cultivar. Therefore, it recommends that red cultivar should be planted sooner on 23rd of August and white cultivar could be planted on 6th and 21st of September. © 2014 PSCI Publisher All rights reserved.

Key words: Planting date, Storage root, Sweet potato, Yield.

Introduction Sweet potato, Ipomoea batatas (L.) Lam., Convulvulaceae), is a dicotyledonous herbaceous that grown widely throughout the tropics and warm temperate regions of the world between latitude 40° and 2300 meter altitude. Sweet potato is the seventh important world food crop after Wheat, Rice, Maize, Potato, Barley and Cassava (Mokhtar et al., 2010; Muli and Agili, 2007). China, Uganda, Indonesia, Tanzania, Vietnam, India and the USA have the highest production. Sweet potato usually has more protein (1-2%) than other tuberous crops such as cassava and Yam. Fresh storage root of Sweet potato is consumed as the steamed, cooked and fried or in the form of chips or snack or by salt and it may also be able to convert into flour or starch. Sweet potato’s leaves are rich of carotene, vitamin A, calcium, fiber and carbohydrate which it is valuable supplement to the diet (Mokhtar et al., 2010; Mais, 2008). The most important sweet potato cultivars are: ‘Beauregard’ and ‘Jewel’ (red skin, orange flesh); ‘Bush Porto Rico’ or ‘Bunch Porto Rico’ (coopercolored skin, light-red flesh); ‘Centennial’ (orange skin, dark-orange flesh); ‘Georgia Jet’ (pink skin, dark-orange flesh); ‘Vardaman’ (golden-yellow skin, dark-orange flesh); ‘Dry-fleshed’ (yellow flesh); ‘Jersey’, ‘Moist-fleshed’ and ‘Garnet’ (dark-red flesh) (Davis, 2008; Lerner, 2009). Comparison the agronomic properties of two Sweet potato cultivars ‘Dan Zaria’ and ‘Dan Bakalori’ should that ‘Dan Zaria’ had more shoot number than other one (Mokhtar et al. 2010). Lauri and Magoro (2008) identified seven white-fleshed and one orange-fleshed varieties of Sweet potato as new varieties to compensate the lack of vitamin A. Evaluation four orange-fleshed Sweet potato genotypes including '199034.1', '199027.3', '199026.1' and '199024.2' accompanying one control varieties ('Mtwapa8') at three times of three, four and five months after harvesting, showed that the number of storage root and marketable storage root in the all genotypes significantly was more than control variety and the best time of harvesting in;199027.3' genotype and control variety recommended four months after planting (Muli and Agili.,2007).

Sci. Agri. 5 (2), 2014: 67-72

In the other study assessed four orange-fleshed and one white-fleshed Sweet potato varieties and demonstrated that main difference between varieties was flavor, density and tissue adherence amount and in second degree tissue firmness. Orange-fleshed varieties were sweeter than white-fleshed varieties (Leighton et al., 2005). Marzouk et al. (2011) compared nine Sweet potato varieties in relation to yield, flesh color, Beta-carotene, starch, sugar and total soluble sugar and released the best varieties. Noda et al. (1997) in evaluation the effect of planting time on starch properties of sweet potato, recommended early planting time to increase gelatin materials and adherence of starch. Parvizi et al. (2011) and Kleinkoph et al. (2003) also observed significant reduction in yield of potato by delaying planting time. Sajedi et al. (2009) also observed about 30-40% reduction in yield and dry matter of tuber by delaying planting time of potato than principle planting time. Eruola et al. (2012) in evaluation Yam (Dioscorea rotundata), yield components compared planting times of 22 nd of March and 5th of June in the first year and 21st of January and 6th of April in the second year of cultivation. They found that in the first year plant length, lateral shoot number, leaf number, tuber weight, tuber number, tuber length, tuber diameter and yield in the early planting time (22nd of March) were significantly more than 5 th of January. But in the second year there was no significant difference between two planting time. Sweet potato is traditionally grown in the south regions of Iran close to Oman Sea. Because of dispersal and low cultivation area of sweet potato, Iran has not been classified in ranking of FAO statistics producer of this crop. This study was assumed to evaluate feasibility of Sweet potato (Ipomoea batatas L.) growing in southern regions of Iran (Minab) and determination the best planting time. Materials and Methods Plant material and treatments This study was performed as factorial arrangement in randomized complete block design by using the sandy soil at Agricultural Research Station of Minab located in 105-km eastern Bandar-Abbas with latitude 27° 10´ and longitude 57° 13´ and 38 m above sea level. The first factor was planting time at three levels including 23 rd of August, 6th and 21st of September and the second factor was cultivar including white skin and red skin cultivars. The main field was divided into four blocks and each block into six plots. Each plot also was divided into three 60-cm creeks and 150-cm stack with 10 meter length. Before culturing, the field was irrigated to supply moisture and sloping of the creeks. The 30-cm cuttings were prepared from Jask region (white cultivar) and Minab region (red cultivar). The cuttings were cultured in both sides of creeks with one meter intervals. Culturing operation was done according to the planting time and the field was periodically irrigated according climate condition. Duration the experiment, irrigation was equally done for all plots along with surface soil drying. Nitrogen fertilizer was used in two times: the first after establishment of the cuttings and growth of the plant to increase vegetative growth and the second in the beginning of storage root production. Weed controlling was performed as hand weeding in two times: 1) two months after cutting and 2) in the end of experiment along with harvesting. During experiment the characteristics such as establishment percent of cutting; plant length; leaf number; lateral shoot number; number of days to storage root production were recorded. At the end of the study, by harvesting plants, the characteristics including storage root length and number, diameter, fresh weight; dry matter and yield, and shoot fresh weight were measured. The vegetative characteristics were measured 75 days after planting. Data analysis The obtained data was analyzed using SAS 9.1 software and the means were compared by Tukey’s test. Results and Discussion Analysis of variance results indicated that planting time had significant influence (p