Information on the combining ability of inbred lines is important in the hybrid maize breeding program. One of the method to estimate the combining ability is by using line x tester method. The research was aimed to determine the general combining ability (GCA) and the specific combining ability (SCA) of maize inbreds. The research was conducted at Bajeng Experiment Station in South Sulawesi, from August to November 2016. The genetic materials consisted of 60 pairs of experimental hybrids derived from 30 lines and two testers. The treatments were arranged in randomized complete block design (RCBD) with three replications. The observed traits were plant height, ear height, grain shelling percentage, grain moisture content, ear length, ear diameter, number of rows per ear, number of grain per row, 1,000 grain weight and grain yield. Results showed lines that had positive and significant GCA on grain yield were G682, G686, G695 and G704. The positive and significant SCA on grain yield character was obtained only in one pair of cross i.e. G685 x N79. The tester line of N79 and MR14 did not show the GCA differences on yield character among tested lines.

Field and incubation experiments were conducted to determine the emission rate of greenhouse gases, nitrogen change, populations of AOB, NOB, and fungi as well as growth of corn in response to amendment of urea granulated with and without nitrification inhibitors and zeolite. The application of urea with neem, urea with zeolite, urea with zeolite + neem, urea with zeolite + dicyandiamide, and urea with dicyandiamide (UD) decreased the N 2 O emissions by 16.3%, 59.6%, 66.8%, 81.9%, 16.3%, and 86.7%, respectively. Meanwhile, patterns of CH 4 fluxes were mostly determined by small emissions. Increase in corn height, weight of cobs, biomass, and chlorophyll leaf contents were not significantly different between urea alone and urea with NIs and zeolite. In the incubation experiment, the highest concentration of NH 4 + and N 2 O production was detected during the first week and it remained high up to the second week of incubation in the combination of urea with NIs and zeolite treatments, although there was no significant difference compared with urea. During NH 4 + decrease, the concentration of NO 3 − started to accumulate from the second to the third weeks. Production of CO 2 showed no significant differences among treatments. The static production of CO 2 could also explain that NIs and zeolite additions did not change AOB, NOB, and fungi activities after the fourth week of incubation. Keywords Emission of N 2 O and CH 4 . CO 2 Production . Dicyandiamide . Neem . Nitrification inhibitor . Zeolite * Oslan Jumadi

Maize (Zea mays L.) production in tropical equatorial regions faces significant challenges due to agroclimatic and soil fertility variability, necessitating the evaluation of maize hybrid adaptability and phenotypic stability across diverse agroecosystems. This study compares the effectiveness of the additive main effects and multiplicative interaction (AMMI) and multi-trait genotype-ideotype distance (MGIDI) models for identifying superior maize hybrids well-suited to the equatorial climate. Fifteen genotypes, including 13 hybrid candidates and two popular commercial varieties (BISI 2 and NASA 29), were analyzed in 10 distinct environments in Indonesia over three consecutive years (2018–2020). The ANOVA method used in the AMMI model analyzed variance into three major components, with PCA analysis indicating that environments (E), genotypes (G), and their interaction (G × E) had a highly significant effect on yield (p < 0.001). Two hybrids, HM04 (CI301032/G102612) and HM02 (CI272022/G102612), displayed high adaptability and stability across various environments, with significantly higher yields than the grand mean by AMMI analysis. Additionally, HM10 (MAL03/CLYN231) and HM09 (G102612/CLYN231) were narrowly adapted to the ME-1 and ME-2 mega-environments, indicating they are best suited for these specific environments. Similar to AMMI, the MGIDI model suggested HM04 (MGIDI index = 1.74) and HM02 (MGIDI index = 1.76) as the two highest-performing hybrids, determined by their yield and nine other traits. Using the multiple trait combination index as a tool to assess the performance of these hybrids enabled researchers to determine the most effective traits for each genotype. The two models are recommended and may be integrated for comprehensive data interaction analysis, which simplifies the process of delineating genotypes with the environment and enables stakeholders to select desired traits while considering their strengths and weaknesses.

<p>Keragaman genetik jagung inbrida diperlukan untuk mendapatkan jagung hibrida yang berpotensi hasil tinggi. Keragaman inbrida dapat dievaluasi melalui analisis molekuler dengan marka simple sequence repeat (SSR). Tujuan  enelitian ini adalah mengevaluasi keragaman genetik jagung inbrida yang berlatar belakang genetik berbeda dengan marka SSR dan mengelompokkannya<br />sebagai panduan untuk pembentukan jagung hibrida. Sebanyak sepuluh marka SSR digunakan untuk mengelompokkan 32 jagung inbrida yang memiliki latar belakang genetik yang berbeda. Analisis dilakukan di Laboratorium Biologi<br />Molekuler, Balai Besar Penelitian dan Pengembangan Bioteknologi dan Sumber Daya Genetik Pertanian, pada bulan Maret 2017. Data polimorfisme SSR pada jagung inbrida dianalisis secara statistik dan filogeninya menggunakan perangkat lunak NTSYS. Hasil analisis keragaman genetik menunjukkan adanya perbedaan antarinbrida, termasuk inbrida yang dihasilkan dari satu populasi jagung bersari bebas. Total sepuluh marka SSR mampu membedakan alel homozigot dan heterozigot jagung inbrida. Dari hasil pengelompokan jagung inbrida pada tingkat kesamaan 68% diperoleh dua klaster. Klaster pertama terdiri atas 30 inbrida, sedangkan klaster kedua hanya terdiri atas inbrida Al-46 dan 22-9-5-4-17-5. Pasangan inbrida dengan jarak genetik terjauh adalah inbrida 22-9-5-4-17-5 dan 23-4-9-7-2-9, dan inbrida CML161/Nei 9008 dan 22-9-5-4-17-5. Inbrida tersebut potensial untuk dijadikan sebagai tetua dalam menghasilkan hibrida karena jarak genetiknya yang relatif jauh.</p>

This research was carried out to study the growth of maize fertilized with a composite of urea with slow release materials (polyacrylate polymer and zeolite) and nitrification inhibitors, Mimba (Azadirachta indica). Three times repetitions of Randomized Block design was used in this study. The parameters observed included biomass (g), the weight of cobs (g) and the length of cobs (cm). The weight and the length of corn cobs were measured after harvest. The result of the study shows that the growth of maize applied with urea fertilizer composited with polymeric polyacrylate, zeolite and Mimba was significantly different from the negative control (KH2PO4/Mono potassium phosphate) fertilizer and appeared to be significantly better than the positive control (Urea and KH2PO4 fertilizers).