Phenotypic characterization of sweet potato (Ipomoea batatas L.) genotypes in Ethiopia for selection of those possessing optimal dual-purpose

This research mainly focuses on the morphological characterization of genotypes of sweet potatoes present in Ethiopia for the selection of those with optimum dual-purpose (as food and feed characteristics). From August to December 2019, alpha lattice design using two replication was performed under fi eld condition for this experiment. At 90 days and 180 Days After Planting (DAP), morphological characterization of the 40 sweet potato varieties based on 16 vine, leaf characters and storage root descriptors was performed. In order to exclude those that clearly did not meet the minimum appropriate value of the descriptors provided for selecting dual-purpose cultivars, fi eld observational yield trials were conducted using CIP descriptors. The data generated in this study, using RSTUDIO software, Agricole kit, Partially Balanced Incomplete Block (PBIB), test function, were subject to Variance Analysis (ANOVA). The substantially different mean values were compared using the Tukey test at the p< 0.05 stage. Cluster and main component analyses were both conducted using SPSS software (version 20.0). There were major differences among the 40 varieties in almost all of the leaf, vine and root characters examined except Central Leaf Lobe (CLL), Petiole Length (PL) and Storage Root Cortex Thickness (SRCT). Calculations based on root to vine ratio formulas were used to classify dual-purpose use varieties. When the 40 sweet potato genotypes were also tested for dual-purpose use, the analysis found signifi cant phenotypic diversity using the data from the calculation and analyzed data from morphological descriptors. Varieties with R/V values in the 0.20.3 range are recommended as dual-purpose high forage varieties, whereas those with R/V values in the 0.3-0.55 range are graded as dual-purpose high root varieties. As a result, 30 varieties can be recommended as dual-purpose based on the root/vine ratio. Research Article Phenotypic characterization of sweet potato (Ipomoea batatas L.) genotypes in Ethiopia for selection of those possessing optimal dual-purpose Selamawit Abebe Gitore1*, Benjamin Danga2, Sylvia Henga2 and Fekadu Gurmu3 1Department of Dry land Agriculture, Faculty of Agricultural Science and Technology, Kenyatta University, Nairobi, Kenya 2Faculty of Agricultural Science and Technology, Kenyatta University, Nairobi, Kenya 3Southern Agricultural Research Center, Hawassa, Ethiopia Received: 03 February, 2021 Accepted: 06 March, 2021 Published: 08 March, 2021 *Corresponding author: Selamawit Abebe Gitore, MSc, Department of Dry land Agriculture, Faculty of Agricultural Science and Technology, Kenyatta University, Nairobi, Kenya, Tel: +254702601280; E-mail:


Introduction
Sweet potato (Ipomoea batatas (L.) Lam) is a crop for food security and plays a major role in Sub-Saharan Africa and Asia. The crop has high yield and return potential and is easily adaptable to a wide range of farming climates, including in ecosystems and farming systems affected by drought stress than other root crops [1]. In addition to the above advantages, sweet potato storage roots are rich in high-calorie starch, with more amylase than amylopectin, a rich source of dietary fi ber, Citation: Gitore  used for the identifi cation of sweet potato cultivars, duplicate accessions, detection of specifi c characteristics and connection with agronomic signifi cance characteristics [5]. For the identifi cation and selection of dual-purpose sweet potato varieties [10], morphological and agronomic characters, such as the storage root to vine ratio, have been used. Agricultural production and productivity were mainly concentrated on cereals in the region, while root crops showed the lowest improvement in seed coverage. Therefore, alternative staple foods, especially sweet potatoes (Ipomoea batatas) have been sought with growing populations and decreasing farm sizes in the region [11]. Neglected/underused crops play a major role in ensuring future food security and can be used directly as alternative crops in the region that are expected to become drought-prone to help farmers generate income and may also be used for further crop development in the breeding program, germplasm resource conservation indirectly.
The main objective of the study is to phenotypic characterization of sweet potato genotypes present in Ethiopia for selection of those possessing optimal dual-purpose characteristics which can be used as a suitable parent for further breeding program.

Description of the study area
The study was conducted At Areka woreda Wolaita Region.
The Wolaita Region is one of the 14 SNNPRR Zones (Figure 1).
The area's capital city is Sodo and it is situated about 420 km south of Addis Ababa (Capital city of Ethiopia). Most of the residents belong to the ethnic community of Wolayita, and their language is Wolaytigna, which is the area's main language.
Based on altitudes at medium, mid and high altitudes, the minerals, antioxidants, fl avonoids, beta-carotene and vitamin A phenolic compounds [2].
Sweet potato is the third most important root crop worldwide after potato and cassava, and ranks sixth in world food crop production (expressed on a dry matter basis) after rice, wheat, potatoes, maize and cassava [3]. However, because of its importance as a food crop, it is ranked fourth in developing countries after rice, wheat, and maize [4]. The crop next to Ensete/false banana (Enseteventricosum (Welw.) Cheesman) is the second best important root crop in Ethiopia [5,6]. The crop is widely cultivated in the country in two states, in the area of Debub/southern and Oromia. Production is intensive in the Debub region, mainly in three zones: the Wolayta zone, the Sidama zone, and the Gamo Gofa zone. Above all, the Wolayta and Gamo Gofa zones are well-known for their sweet potato production and the people in these zones are very dependent on sweet potatoes for food security and during the famine period [7]. The majority of smallholder farmers practice mixed farming due to a scarcity of land. These projects provide evidence that the amount of livestock fodder available is inadequate in terms of both quality and quantity [8].
Therefore, dual-purpose sweet potato has become an important crop in maize-based farming systems where it can be planted off-season to meet food safety requirements [9]. Since feed is increasingly scarce, its vines are often used as feed for livestock. High yields, good nutritional quality and low input requirements make sweet potato a potential remedial crop for many rural farmers under marginal conditions [10]. Moreover, in areas where land supply is slowly declining, its usefulness for both food and feed makes it suitable [9].
Sweet potato morphological characterization is performed by assessing differences in the characteristics of the plant, leaf, fl ower and storage root [9]. This approach was previously Wolayita region is stratifi ed. The study area covers a portion of the region between 7o4 'N37o42' E and 7o4 'N37o42' E. The average annual precipitation in the areas of the Wolaita region is about 1300 mm in the highlands and midlands, respectively.
Whereas in the lowland areas is up to 600 mm or even less. With the highest rains occurring in June-September and short rains in February-March, rainfall is bimodal. More unpredictable and unreliable are the short rains (Belg). In the area, failure of either or both rains triggers shortages. The average daily temperature ranges from 15oC to 30oC. The Wolaita region, like the eastern part of Ethiopia, is also heavily affected by drought.

Experimental materials
For the morphological characterization analysis, forty selected sweet potato accessions that have already been introduced from the CIP Kenya to Ethiopia and germplasm advanced from the crossing experiment performed by the Hawassa Agricultural Research Center [10] in Ethiopia were used Table 1. Centre) (CIP), AVRDC and IBPGR [12] were used Table 2. In order to exclude those that clearly did not meet the minimum appropriate value of the descriptors provided for selecting dual-purpose cultivars, fi eld observational yield trials were conducted using CIP descriptors.

Calculations for classifi cation of varieties in two dualpurpose
Classifi cation of dual-purpose use varieties was done based on Leon-Velarde, et al. 2001 [14].

Statistical analysis
The data generated in this study was subject to Variance Analysis (ANOVA) using the Agricole package RSTUDIO software.   (Table 3).

Root characters
Among the 40 varieties, most of the root characters (Table   4) Table 5.  Ground Cover/ Estimated percentage of ground cover will be recorded High (75%-90%) 7

Genetic relations of varieties based on phenotypic characters
Vine Internode/ 3 internode positioned in the middle section of the vine will be measured. Citation: Gitore

Principal component analysis
This PCA was performed for all the 16 morphological traits among the 40 sweet potato varieties.PCA revealed 5 principal   Citation: Gitore Table 6.

Conclusions and recommendations
For the selection of those with optimal dual-purpose characteristics that can be used as a suitable parent for further breeding programs, the research sought to morphologically classify sweet potato genotypes. Dual-purpose sweet potato Citation: Gitore     allows for a limited number of toppings, so that fodder supplies can be spread throughout the year without dramatically impacting root yields [9]. All spreading species with high ground cover, which is an indication of the availability of fodder, were the varieties selected in this study. With the exception of Petiole length (PL) and Central Leaf Lobe (CLL), all the leaf characters and vine characters evaluated among the varieties were extremely varied. This is because environmental factors affect these characters. The effi cient method is the selection of dual-purpose sweet potato varieties based on the root/vine ratio aimed at those varieties that optimize vine production while preserving good storage root productivity [9].