International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Index Copernicus Value (2013): 6.14 | Impact Factor (2015): 6.391 Volume 5 Issue 7, July 2016 www.ijsr.net Licensed Under Creative Commons Attribution CC BY Correlation Analysis of Yield and Yield Components of Seven Soybean Cultivars on Weed Competition Doni Hariandi 1 , Didik Indradewa 2 , Prapto Yudono 2 1 Graduate Student, Department of Agronomy, Faculty of Agriculture, Gadjah Mada University, Indonesia 2 Department of Agronomy, Faculty of Agriculture, Gadjah Mada University, Indonesia Abstract: The research aims to determine the variable yield components that correlate to the yield of soybean cultivars and to obtain soybean cultivars that are able to maintain yield despite competition with weeds. This field research is arranged using split plot with three blocks as the repetition where the main plot is the weed treatments and those are weed-free, weeding in a critical period, and weedy. Sub-plot is the soybean cultivars which are Anjarmoro, Argomulyo, Burangrang, Gema, Gepak kuning, Kaba, and Wilis. The research’s result shows the variable yield component effects to seed yield is the number of pod per plant, number of seed per pod and seed weight per plant. Cultivars which can survive from three kinds of the conditions (weed-free, weeded in a critical period, and weedy) are Anjasmoro cultivar and Kaba cultivar. Keywords: Soybean, cultivar, weed, endurance, yield 1. Introduction Soybean is one of the food commodities of Indonesia and also as a staple food other than rice. Soybean is a source of vegetable protein and widely consumed in Indonesia. Soybean demand in Indonesia is increasing from year to year but the production of itself is still sufficient according to Agricultural Ministry year 2015. Indonesian government still imports the soybean commodity from other country. The decreasing of the soybean production is caused by many factors as location, low price, bad seed, also less technology (Adisarwanto dan Wudianto, 1998 cit. Hendrawan, 2000), another factor is also the weed competition. Weed can decrease the quality production of the plant. Weed also could increase the quantity of the production of the plant. The weed also impacts on the plant’s growth. The decrease of the plant production of soybean plant is caused by weed reach at the lever 18-76% (Manurung and Syam’un 2003). This research aims to determine the variable yield components which has correlation at the production of the of soybean cultivars and to achieve soybean cultivar that can produce better production. 2. Materials and Methods The research was held at Education and Research Garden and Development (KP4) Gadjah Mada University which located at Kalitirto, Berbah, Sleman, Yogyakarta, Indonesia. This research started on November 2015 till March 2016. Materials used are seven soybean seeds with different cultivars, fertilizer (Urea, SP-36 and KC1), and pesticide. The tools utilized for this research are farming tools, ruler, camera, rope, scissor, stationery, knife, cutter, plastic bag, paper bag, pail, scale, oven, and moisture tester. This field research is arranged using split plot with three blocks as the repetition where the main plot is the weed treatments and those are weedy, weeding in a critical period, and weed-free. Sub-plot is the soybean cultivars which are Anjarmoro, Argomulyo, Burangrang, Gema, Gepak kuning, Kaba, and Wilis. Soybean cultivars are given by Balai Penelitian Tanaman Kacang-kacangan dan Umbi-umbian Malang, Indonesia. The data result of observation uses ANOVA analysis and Duncan’s New Multiple Range Test (DMRT) at 5% level. The analysis uses correlation analysis to determine between variable yield components and the data result would also be analyzed using regression analysis. However, to evaluate cultivars that can survive on three kinds of conditions including weed-free, weeding in a critical period, and weedy would use statistic method with Genotype and Genotype by Environment Interaction Biplot (GGE Biplot). 3. Results 3.1 Number of pod per plant The analysis result in Table 1 shows that the interaction between the weeds and cultivars toward the number of pod per plant. The weed-free treatment shows that Gepak kuning cultivar have highest number of pods per plant compared to the other cultivars. Kaba cultivar shows that the highest number of pods per plant in the weeding treatment, but it is not different with Gepak kuning kultivar, while on weedy treatment Gepak kuning cultivar shows the highest number of pods per plant, but not significantly different with Kaba cultivar. Paper ID: ART2016605 DOI: 10.21275/v5i7.ART2016605 2151