Orange-Fleshed Sweet Potato (OFSP) is an important crop in Indonesia. Yield potential and genotypic adaptability are important factors in varietal development. The purpose of this study was to estimate the stability of yield and to select the best OFSP genotypes across three agroecosystems in West Java, Indonesia. The field trials used were augmented design with 50 F1 Orange-Fleshed Sweet Potato (OFSP) genotypes as treatment, and seven check varieties as controls. The experiments were conducted in three different agroecosystems in West Java (Sumedang, Bandung, and Karawang). Selection was based on physical characteristics of sweet potato tuber, yield and stability across three environments. Data analysis of the yield characters, yield component, and tuber quality were performed by combined variance analysis. Selected genotypes were analyzed for stability yield using the parametric, non-parametric, Additive Main effects and Multiplicative Interaction (AMMI), AMMI Stability Value (ASV), and Genotype and Genotype by Environment (GGE) biplot models. Results identified the top best ten F1 genotypes namely F1-38 (G1), F1-69 (G2), F1-71 (G3), F1-77 (G4), F1-127 (G5), F1-128 (G6), F1-135 (G7), F1-159 (G8), F1-191 (G9), and F1-226 (G10). Location showed a significant effect on yield. Genotypes F1-069, F1-077, F1-226, F1-038, and F1-128 have the lowest ASR based on non-parametric and parametric stability models and there were identified as the most stable. AMMI analysis identified F1-128, F1-135, F1-038, and F1-069 as the most stable genotypes. F1-38 (G1), F1-69 (G2), F1-128 (G6) were found to be the most stable genotypes based on ASV analysis, while GGE biplot identified F1-38 (G1) and F1-69 (G2) genotypes as the stable genotypes. Other genotypes were considered to as location-specific. Based on AMMI, ASV, and GGE Biplot models, F1-038, and F1-069 were identified as stable genotypes. They produced higher yields than other genotypes. Therefore, the F1-038 and F1-069 genotypes can be potentially recommended as superior varieties for West Java, Indonesia.

There are many local varieties of sweet potatoes which are cultivated and consumed in Indonesia. The food industry which uses sweet potato as the main raw material has been developed in West Java. Demand for orange-fleshed sweet potato is high, but the supply of demand has not been fulfilled. This is because the varieties that are widely cultivated do not meet consumer standards and preferences, so new superior genotypes are needed following demand. Currently, selection of stable and high-yielding genotypes and accordance with consumer and industry preferences is one of the focuses of sweet potato research. Orange-fleshed sweet potato multi locations testing in accordance with consumer and industry preferences, can be used as a basis for consideration in the development program. The purpose of this study were to identify genotype by environment interactions (GEIs) and t select superior genotypes and to estimate yield stability across three locations in West Java, Indonesia. Combined analysis of variance (ANOVA) was used to determine significant differences between each genotype tested in term of yield and to estimated genotype by environment interactions (GEIs). Additive Main Effects and Multiplicative Interaction (AMMI), Genotype Plus Genotype by Environment Interactions (GGE) biplots, and Parametric and non-parametric stability measurements were used to determine yield stability from genotypes tested in all locations (Sumedang Regency, Bandung Regency, Karawang Regency). Data in this article showed that the genotypes, environments, and GEIs had an effect on sweet potato yields, with influences of 35.03%, 18.87%, and 46.01%, respectively. The results in this data also indicate that some new sweet potato genotypes have stable and high yields in three environments in West Java, Indonesia. So they were can be used for development in sweet potato breeding programs.

Cilembu sweet potato is a unique commodity with high demand market due to its sweet taste. The objectives of this study were to investigate the production performance of Cilembu sweet potatoes in term of production classes and critical limit and to determine discriminating land characteristics classes of yield and total sugar content. This study was conducted in Cilembu sweet potatoes production centers in West Java. Sweet potatoes tuber and soil samples were collected by purposive random sampling during harvest. Cilembu sweet potatoes production classes were defined by decreasing yields criteria in land evaluation. Critical limit production was the lowest yield and total sugar content of raw tuber which harvested in Cilembu village. Discriminating land characteristics were decided by discriminant analysis. Results showed that there was a significant different yield between typical and nontypical areas. Critical limit of yield and total sugar content were 10.5 t ha-1 and 2.32 %, respectively. The discriminating land characteristics of yield classes were soil properties (pH, CEC, P, Ca, Mg, ΔT), and monthly rainfall, whereas for total sugar content classes were effective soil depth, clay, sand and monthly rainfall. These variables are proposed as diagnostic criteria in Cilembu sweet potato land suitability criteria.

One of the emerging topics in agriculture is application of biophysical method such as the use of magnetic field (MF) to treat seeds for improved plants production. An experiment has been carried out to determine the effect of MF exposure on sorghum seeds and its subsequent growth in soil. The treatments were different strength of MF (control, 1 mT, 6 mT) and exposure duration (5, 10, 15 min). The magnetically treated seeds showed higher seed germination percentage, vigour index, seed germination index, seedling growth, plant growth and chlorophyll content compared to non-magnetically treated seeds. The best duration of MF exposure was 15 minutes, either at MF strength 1 mT or 6 mT. It is suggested that pre-sowing MF treatment has the potential to improve crop productivity through the enhancement of germination, seedling emergence, and growth of plants.

Cilembu sweet potato is one of the famous local sweet potatoes in Indonesia. The aim of this study is to determine biophysic factors related to Cilembu sweet potato production based on local knowledge and field data. The research was conducted between September 2014 and October 2015. The methods used simple analytical hierarchy processes and selection guide of land use requirements for local knowledge exploration and Pearson correlation for biophysic factors related to Cilembu production. The samples of study include expert farmers, sweet potatoes and soil samples were selected using purposive sampling technique. The samples of soil and sweet potato were collected during harvest from each cultivation field. The result showed that soil and climate are the dominant environmental factors affecting Cilembu sweet potato production based on farmer perceptions. Correlation analysis confirms the farmers' perception analysis and the field data shows that soil and climate factors have significance correlation to yield and sugar content of Cilembu production. This study is useful for preliminary stage of local varieties land suitability criteria development, more so in the situation of limited data and expertise on the topic.