Selection of high yielding and stable maize hybrid requires effective method of evaluation. Multienvironment evaluation is a critical step in plant breeding programs that is aimed at selecting the ideal genotype in a wide range of environments. A method of evaluation that combines a variety parameter of stability could provide more accurate information to select the ideal genotype. The aims of the study were (i) to identify the effect of genotype, environment, and genotype × environment interactions (GEIs) on maize hybrid yields and (ii) to select and to compare maize hybrids that have high and stable yields in diverse environments in Sumatra Island based on combined analysis, selection index, and GGE biplot. The study was conducted in five different environments in Sumatra Island, Indonesia, using a randomized complete block design repeated three times. Data were estimated using combined variance analysis, parametric and nonparametric stability, sustainability index, and GGE biplot. The results showed that the genotype had a significant effect on maize hybrid yields with a contribution of 41.797%. The environment contributed to 24.314%, and GEIs contributed 33.889% of the total variation. E1 (Karo, South Sumatra; dry season) and E3 (Tanjung Bintang, Lampung; dry season) were identified as the most ideal environments (representative) for testing the hybrids for wider adaptability. The maize hybrid with high and stable yields can be selected based on combined stability analysis and sustainability index as well as GGE biplot. These three methods are effectively selected high yielding and stable genotypes when they are used together. The three maize hybrids, namely, MH2, MH8, and MH9, are recommended as high yielding and stable genotype candidates.

Determination of grain yields of stable and high-yielding maize hybrids in a wide environment requires high accuracy. Many stability measurement methods have been used in multi-environment experiments. However, the relationships among the different methods are still difficult to understand. The objectives of this study were to 1. Identify the effect of growing season and location (Environments = E), hybrids (Genotypes = G), and their interactions (GEIs) on grain yields; 2. Select high-yielding and stable maize hybrids in a wide range of environments; 3. Determine the relationship between each stability estimation; and 4. Determine the mega-environment of maize hybrid and identify the best locations for testing. Field experiments were conducted at ten locations in Java Island, Indonesia, for two growing seasons using a randomized completed block design with three replications. The experimental results showed that the main effects of the growing season, location, hybrid, and GEIs, significantly affected maize hybrid yields. Stability estimations of TOP, S⁽³⁾, S⁽⁶⁾, NP⁽²⁾, NP⁽³⁾, KR, NP⁽⁴⁾, CV_i, and b_i, belong to the concept of dynamic stability that can be used to select maize hybrids in favorable environments, while other estimations were classified as in the static stability. Three maize hybrids were successfully selected, with high and stable yields based on numerical and visual stability estimations, namely SC2, SC7, and SC9. The three hybrids can be used as candidates for sustainable maize development programs. The dry season, the rainy season, and the combination of two growing seasons produced three mega-environments. GJRS and KARS were the most discriminative environments. Both environments can be used as favorable environments for selecting the ideal maize hybrid.

Dewayani, Maulana H, Wicaksana N, Suganda T, Concibido V, Karuniawan A. 2021. Distribution and prevalence of scurf (Monilochaetes infuscans) on sweet potato (Ipomea batatas) in West Java, Indonesia. Biodiversitas 22: 2876-2883. Scurf (Monilochaetes infuscans) is a common sweet potato (Ipomoea batatas (L.) Lam.) tuber skin discoloration disease, that can cause significant yield loss, especially when tubers are destined for the export market. Despite the economic importance of the disease in West Java, Indonesia, there is a dearth of information on the distribution and severity of scurf disease. To address this gap, a disease survey was carried out across 28 fields in six districts (Bandung, Sumedang, Garut, Kuningan, Cianjur, and Bogor) of West Java from 2016 to 2018. Scurf disease prevalence was recorded by counting the number of infected tubers from 15 plant samples per field. Disease incidence was recorded when at least one infected tuber per plant was observed. Severity of scurf diseases was estimated by measuring the percentage of infected surface area, using AutoCAD map 2019. Results show that scurf was distributed across all locations surveyed. Disease incidence ranged from 1.68% (Cikadu) to 27.56% (Cilembu) while disease severity ranged from 7.92% (Cikadu) to 57.00% (Cilembu). Based on potato dextrose agar (PDA) culture plates, 68.57 % of tubers were infected with various fungi. Among them, M. infuscans (32.14 %) was the most prevalent and most widely distributed pathogen associated with the scurf disease across sweet potato fields in West Java, Indonesia. To effectively manage the disease and improve farmers’ income, it is imperative to establish effective and sound integrated disease mitigation strategies based on the results of this survey.

Bawang merah (Allium cepa L. var aggregatum) salah satu komoditas hortikultura banyak di konsumsi. Peningkatan permintaan dalam kuantitas dan kualitas untuk komoditas ini meningkatkan ketersediaan varietas unggul. Penelitian dilakukan untuk menduga keragaman genotipe dan fenotipe serta nilai heritabilitas karakter pertumbuhan, komponen hasil dan hasil bawang merah di tiga lokasi dataran tinggi (Lembang 1.250 m dpl, Kab. Bandung Barat; Pacet 971 m dpl, Kab. Bandung; dan Samarang, 970 m dpl, Kab. Garut). Penelitian dilaksanakan dari September sampai Nopember 2019. Materi genetik yaitu 12 genotipe bawang merah terdiri dari 7 klon: B1, B19, B63, B72, B77, B102, dan B222, serta 5 varietas: Trisula, Bali Karet, Maja Cipanas, Bima Brebes dan Sumenep. Rancangan percobaan menggunakan Rancangan Acak Kelompok (RAK) dengan 3 ulangan. Hasil analisis ragam menunjukan genotipe berpengaruh sangat nyata terhadap seluruh karakter pertumbuhan, komponen hasil, dan hasil. Nilai koefisisen keragaman genotipe dan fenotipe yang tinggi diperlihatkan oleh karakter persentase tanaman berbunga (48,10 % dan 49,01 %), berat basah per umbi (29,71 % dan 30,87 %), dan berat kering per umbi (33,17 % dan 34,29 %). Nilai duga heritabilitas arti luas (H_bs) karakter pada 12 genotipe bawang merah berkisar antara 45,08-96,30 %. Semua karakter yang diuji memiliki nilai heritabilitas tinggi kecuali untuk karakter jumlah daun per rumpun nilai heritabilitasnya sedang. Seleksi bawang merah di dataran tinggi dapat dilakukan pada generasi awal.Abstract Shallots (Allium cepa L. var aggregatum) are one of the most widely consumed horticultural commodities in Indonesia. Increased demand in quantity and quality for this commodity improved availability varieties. A study was conducted to estimate variability of genotypes and phenotypes as well as the heritability value of growth characters, yield components, and yields of shallot at three highland locations (Lembang 1.250 m asl, West Bandung District; Pacet 971 m asl, Bandung District; and Samarang 970 m asl, Garut District). The research was conducted from September to November 2019. The genetic material studied was 12 genotypes of shallots consisting of 7 clones: B1, B19, B63, B72, B77, B102, and B222, and 5 varieties: Trisula, Bali Karet, Maja Cipanas, Bima Brebes, and Sumenep. Every experiments in all locations was arranged in Randomized Block Design (RBD) with 3 replications. The analysis of variance results showed that the genotype had a very significant effect on all growth characters, yield components, and yields. High variation coefficient values of genotype and phenotype was found in the character of percentage of flowering plants (48.10% and 49.01%), freshweight per bulb (29.71% and 30.87%), and dry weight per bulb (33.17% and 34.29%). All characters tested had a wide phenotific variability. The estimated value of heritability (broad meaning) of the characters in 12 shallot genotypes ranged from 45.08 to 96.30%. All characters tested has high heritability except for the number of leaves per clump the heritability was moderate. The study is the shallot selection in the highlands can be carried out in the early generations.

Piramidisasi gen adalah upaya untuk menggabungkan beberapa gen yang menguntungkan dari banyak tetua menjadi satu genotipe tunggal. Hasil tinggi, tahan terhadap wereng cokelat, kandungan amilosa sedang, umur genjah dan aromatik adalah beberapa sifat yang diharapkan untuk digabungkan. Melalui teknik piramidsasi, telah diperoleh 28 genotip, namun analisis kekerabatan genetik, sebagai pertimbangan dalam pengambilan keputusan pada tahapan pemuliaan selanjutnya, belum dilakukan. Kombinasi gen ini dicapai dengan persilangan banyak genotipe tetua dengan karakter unggul yaitu Sintanur (aromatik), Pandan Wangi (aromatik), IR64 (kandungan amilosa sedang), PTB33 (tahan wereng coklat), Ciapus (hasil tinggi) dan KA (umur genjah). Tujuan percobaan ini adalah untuk memperoleh hubungan genetik genotip dalam sifat-sifat agro-morfologi dan marka molekuler. Analisis hubungan kekerabatan antara tetua dan 28 genotip piramidisasi dilakukan menggunakan software XLSTAT2016 untuk membentuk matrik similarity shared allele distance dengan koefisien Jaccard sebagai pembentuk jarak genetik untuk marka molekuler dan koefisien korelasi pearson untuk marka fenotipik. Kemudian dilakukan pengelompokan atau clustering dengan metode Unweighted Pair Group Method with Arithmetic Averages (UPGMA). Hasil pengelompokan berdasarkan marka molekuler dengan menggunakan 11 marka yang terkait erat dengan tujuh karakter target, diperoleh koefisien kemiripan sebesar 41,3% dan terbentuk dua kelompok, sedangkan hasil pengelompokan berdasarkan marka fenotipik dengan 14 karakter agro-morfologi terbentuk tiga kelompok dengan tingkat kemiripan 22,2%. Genotipe SPxCAKA1B, SPxPP3B dan PPxIP4B dapat dimanfaatkan sebagai tetua atau genotipe harapan karena memiliki jarak kekerabatan yang paling jauh diantara genotip lainnya.