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Sweet potato weevil Cylas formicarius (Fab.) is the main obstacle for sweet potato production in various countries. Root damage caused by C. formicarius larvae reduced root yield up to 100%. The aim of this study is to test the measures using mulch and entomopathogenic fungus Beauveria bassiana for controlling C. formicarius in endemic land of entisol type. The control measure tested was the use of straw mulch and plastic mulch as well as the application of the entomopathogenic fungus Beauveria bassiana. The research was conducted at the experimental station at Indonesian Legumes and Tuber Crops Research Institute, Malang from July to December 2018. The results showed that the measure for controlling C. formicarius using straw or plastic mulch combined with the entomopathogenic fungus B. bassiana produces root yields between 17 and 26 t/ha. Using plastic mulch as a cover for mounds with the application of the fungus B. bassiana is more effective and efficient in controlling C. formicarius than the insecticide deltamethrin. Plastic mulch can physically inhibit the process of laying eggs and the formation of C. formicarius larvae, while B. bassiana is toxic to eggs, larvae, and adults of C. formicarius. The efficacy of control measure using plastic mulch and the application of B. bassiana can reduce yield losses by up to 96.76%. Technological innovation using plastic mulch to cover the mound with the application of the entomopathogenic fungus B. bassiana can be recommended to control C. formicarius on land endemic to the entisol type.

Black soybean (Glycine soja (L.) Merril) is one of the potential agricultural commodities in Indonesia. The multilocation trial is the primary requirement for variety release before farmers can widely use the new varieties. Various stability measurements on grain yields will provide more accurate information in selecting superior lines. The aims of the study were to: (i) identify the effect of genotype by environment interactions (G×E) on black soybean grain yields; (ii) select the black soybean lines with stable and high grain yields in different agroecosystems; and (iii) determine the best representative environment for testing black soybean lines. The field trials used an augmented design that was applied in three blocks for each location. The research was conducted in West Java, Indonesia, specifically in Sumedang, Indramayu, and Majalengka. The three locations are traditionally soybean production areas in West Java. The results showed that G×E significantly affected grain yields, with a contribution of 38.35%. Based on the results of stability testing using parametric, non-parametric, and genotype plus genotype by environments (GGE) biplot measurements, the G13, G22, G25, and G26 lines were considered the most stable and produced the highest yields in the three agroecosystems. In addition, Sumedang is the most representative location for testing black soybeans in Indonesia. Therefore, the four lines can be proposed as new superior lines for black soybeans with high yields and stability in three environments. Information about the relationship between the yield stability parameters can be used for the most accessible parameter selection.

Identification of soybean genotypes including potential yield character is a base to understand soybean growth, development, and productivity on potential lands. The purpose of this research is to determine the potential yield of soybean genotype and their supporting components in tidal land type C. Four soybean genotypes and two comparative varieties Anjasmoro and Lawit (adaptive tidal land) were tested on tidal land type C at four locations (three locations in Jambi Province and one location in South Kalimantan Province), July 2017. The research was conducted using a randomized design and repeated four times in each location. The plot size was 12 m2, spacing row 40 cm x 15 cm, two plants for each hole. GH_KR_13, GH_GR_1 and GH_GR_5 productivity equal with Lawit, the adaptive variety for tidal land type C. While, Anjasmoro showed more than 2.20 t/ha in seeds productivity, 54 filled pod for each plant, with large seeds (15.84 gram/100 seeds). Anjasmoro had higher seed productivity than all of genotypes including Lawit. Anjasmoro with it's potential yield and productivity, can cofarmer preferences and deserve to be developed in tidal land type C. [ABSTRACT FROM AUTHOR]