Judul: Morphophysiological Characters, Quality, and Physicochemical of Rice from Five Varieties of Rice using Microbial-enriched Organic Fertilizer
Abstrak: The excessive use of chemical fertilizers and pesticides in rice cultivation has an impact on the degradation of agricultural land. The role of microbial enriched organic fertilizer as a source of soil organic matter is an option in overcoming land degradation and decreasing crop productivity. Microbes such as Azospirillium, Azotobacter, Bacillus, and Pseudomonas can increase the availability of soil nutrients so that plants quickly absorb them. This study aims to determine the morphology, physiological character, quality, and physicochemical of five rice varieties with various doses of microbial-enriched organic fertilizer, and to determine the optimum dose of microbial-enriched organic fertilizer for each rice genotype. This research was carried out from July 2020 to January 2021 at the Sawah Baru Experimental Site, Faculty of Agriculture, IPB University, and from March 2021 to September 2021 at the Laboratory of Applied Sciences, Faculty of Agricultural Technology, IPB University. The experiment was carried out using a Split-plot Design with 3 replications. The main plots were doses of organic fertilizer enriched with microbes consisted of 0, 10, 20, and 30 tons ha-1 , and the sub-plots, namely rice varieties including IPB 3S (a new type of rice), Inpari 24 (brown rice inbred), Hipa 18 (hybrid), Inpari 32 (new high yielding variety), and Tarabas (japonica). The data were analyzed using Analysis of variance (ANOVA) followed with the Duncan Multiple Range Test (DMRT). The results showed that the application of microbial-enriched organic fertilizer significantly increased plant height, number of tillers, root dry weight, shoot dry weight, leaf greenness, number of grain per panicle, and productive tillers. Applying 30 tons ha-1 of organic fertilizer can increase dry grain weight per plant by 25.78%. The yield of grain produced after applying 10 to 30 tons ha-1 of organic fertilizer increased by 12.91% to 32.5%. The application of organic fertilizer up to 30 tons ha-1 still increase grain productivity per hectare therefore the optimum dose for microbial-enriched organic fertilizer cannot be determined yet. Physicochemical analysis showed that the application of microbial-enriched organic fertilizer resulted in rice yields ranging from 64.6 to 64.9%. Inpari 24 (brown rice inbred) and Tarabas (japonica rice) had the lowest amylose content. The results of the cooking properties analysis showed that Inpari 24 had moderate gel consistency. Consumer preferences from organoleptic test results liked the color, aroma, taste, and texture of rice at all doses of microbial enriched organic fertilizer and the five rice varieties.
Keyword: gel consistency, hybrid, microbes, nutrient uptake, viscosity

Judul: Application of Zn Fertilization to Increase Yield and Concentration of Zn in Rice on Four Rice Varieties
Abstrak: Penelitian ini bertujuan untuk mendapatkan informasi tentang respon varietas terhadap Zn dalam pertumbuhan, komponen hasil dan kandungan Zn dalam beras pada padi varietas IPB 3S, Akita Komachi, Hipa 18, dan Inpari 42. Penelitian dilaksanakan di Kebun Percobaan IPB Sawah Baru, Departemen Agronomi dan Hortikultura, Fakultas Pertanian, IPB pada Januari hingga Juli 2020, dilanjutkan di Laboratorium Pasca Panen, Laboratorium Uji dan Laboratorium Technopark hingga bulan Agustus 2020 Rancangan percobaan yang digunakan adalah rancangan split plot yang terdiri atas dua faktor yaitu varietas sebagai petak utama dan dosis pupuk Zn sebagai anak petak. Perlakuan varietas terdiri dari varietas IPB 3S, Akita Komachi, Hipa 18, dan Inpari 42. Perlakuan dosis Zn terdiri atas lima taraf dosis 0 kg ha-1, 4 kg ha-1, 8 kg ha-1, 12 kg ha-1 dan 16 kg ha-1. Satuan percobaan yang digunakan petakan seluas 25 m2. Hasil penelitian menunjukkan bahwa varietas memiliki karakter yang berbeda pada peubah yang diamati, meliputi seluruh peubah vegetatif, biomassa dan panen, kecuali peubah bagan warna daun lima MST, bobot basah akar dan tajuk fase vegetatif, dan volume akar fase panen. Aplikasi pupuk Zn berpengaruh nyata terhadap peubah persentase rendemen beras, beras kepala, beras pecah, dan beras menir. Perlakuan dosis pupuk Zn tidak berpengaruh terhadap pertumbuhan, hasil, komponen hasil maupun kandungan Zn dalam beras. Tidak terdapat respon yang berbeda antar varietas terhadap aplikasi dosis pupuk Zn, The objective of this research was to obtain information on the effect of Zn application on growth, crop yield and Zn content in rice grain of IPB 3S, Akita Komachi, Hipa 18 and Inpari 42. The research was conducted at Sawah Baru Experimental Field, Department of Agronomy and Horticulture, IPB University from January to July 2020, and at the Post-Harvest Laboratory, Test Laboratory and Technopark Laboratory until August 2020. The experimental design used in this research was split plot design with two factors, i.e. variety as main plot and dose of Zn fertilizer as subplot. The factor of variety consisted of IPB 3S, Akita Komachi, Hipa 18, and Inpari 42. The factor of Zn fertilizer dose consisted of five levels 0 kg ha-1, 4 kg ha-1, 8 kg ha-1, 12 kg ha-1 and 16 kg ha-1. The experimental unit was a plot of 25 m2. The result showed that variety has different characteristics on vegetative variables, harvest variables, and harvest biomass variables except on leaf index color on 5 WAT, root’s and shoot’s fresh weight in vegetative phase, and root’s volume at harvest. The application of Zn fertilizer affects the variable of milled rice percentage, head rice, broken rice and rice groats percentage. Application of Zn fertilizer didn’t affect growth, yield, yield component and Zn content on rice. There are no different responses between variety on application of Zn fertilizer.
Keyword: biofortification, micro nutrient, rice production, zinc

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf