Advances in Life Science and Technology www.iiste.org ISSN 2224-7181 (Paper) ISSN 2225-062X (Online) DOI: 10.7176/ALST Vol.70, 2019 19 Evaluation of the Effects of Intra and Inter Row Spacing on the Growth and Yield of Ground Nut (Arachis Hypogaea L.) at Haro Sabu, Western Ethiopia Teshome Gutu*, Dereje Abera and Biru Alemu Oromia Agricultural Research Institute, Haro Sebu Agriculture research center Abstract Ground nut (hypogaea L.) is one of most important food crop grown in Oromia Regional State, Ethiopia. However, its productivity is very low due to inappropriate intra and inter spacing practice. Thus,the study was conducted in 2016 and 2017 during the main cropping season at Haro Sabu Agricultural Research Center and Kombo subsite of Kelem Wollega zone of Western Ethiopia to identify the effects of different spacing on growth parameters, yield and yield components of ground nut varieties. The experiment was laid out in Randomized complete Block design with three replications in factorial arrangement. The experiments was consist of two factors. Nine levels of spacing were 50cmx5cm, 50cmx10cm, 50cmx15cm, 60cmx5cm, 60cmx10cm, 60cmx15cm 75cmx5cm, 75cm x10cm, 75cm x15cm and two varieties (Manipinter and Sartu). The highest total number of pods per plant (21.36) was obtained from variety manipinter. Regarding to spacing, the highest number of pods per plant (25.00) was obtained from 75cmx10cm and followed by 75cmx15cm(22.45) . The highest hundred seed (66.85g) weight and grain yield (2105 kg ha -1 ) was recorded from manipinter variety. Regarding to spacing, the highest grain yield (2474 and 2433 kg ha -1 ) was obtained from 50cmx5cm and 60cm x5cm respectively. The highest net benefit (50269.00 and 50245.00 ETB ha -1 ) was recorded from 50cmx5cm and 60cmx5cm spacing respectively. However the highest marginal rate return (288.46%) was recorded from spacing 60cm x 5cm followed by 50cm x 5cm (2.66%). Therefor spacing of 50cmx5cm and 60cmx5cm was optimum plant population density for production of ground nut in Kelem Wollega zone of western Ethiopia. Keywords: Arachis hypogaea L., grin yield, interaction effect, spacing DOI: 10.7176/ALST/70-04 INTRODUCTION Groundnut (Arachis hypogaea L.) is an important monoecious annual legume used for oilseed, food and animal feed (Pande et al., 2003; Upadhyaya et al., 2006). It is the main source of food in various forms and used as a component of crop rotation in many countries (Gbèhounou and Adengo, 2003). Groundnut is grown on 26.4 million ha worldwide with a total production of 38.2 million metric tons (FAOSTAT, 2010). Developing countries account for 97% of the world’s groundnut area and 94% of the total production. The lowland areas of Ethiopia have considerable potential for increased oil crop production including groundnut. The estimated production area and yield of groundnut in Ethiopia in 2016/2017 cropping season were 74861.37 hectares and 1296364.18 quintals, respectively (CSA, 2017).The seed yield is a function of interaction between genetic and environmental factors including soil type, sowing time and method, seed rate, fertilizers and time of irrigation among which, row spacing plays a vital role in getting higher yield (Hussain et al., 2003). Proper spacing ensures adequate ventilation, reduces competition among plants for space and nutrients, and reduces transmission of diseases, facilitates weeding and movement in the farm and also reduces overcrowding and, therefore; allows interception of radiation by plant canopies. The response of ground nut to plant density has been investigated in many areas of the world. Investigation of growth and yield performance of ground nut with special reference to arrangement has been conducted and the result showed that leaf area index, crop growth rate, pod growth rate, pod and kernel yield have increased by increasing plant density (Kiniry et al., 2005). Cultivation of groundnut in narrow rows can lead to maintenance of a complete crop cover over the soil which inhibits weed seed germination and reduces the need to carry out weeding (Lee et al., 1994). Early canopy closure by closely spaced groundnut crop has been shown to smother weeds hence reducing weed/crop competition, especially for soil nutrients and water. Such benefits are more evident under low input conditions as seen on most smallholder farms. Some investigators concluded that narrow row spacing was superior in yield and more economical than broader rows (Pereira et al., 1988). Plants growing in too wide rows may not efficiently utilize the natural resources such as water and nutrients, whereas growing in too narrow rows may result in sever inter and intra- row spacing competition (Ali et al.,1999). Therefore, it is of crucially important to manipulate the row spacing in order to increase plant productivity. Production of groundnut is under progress since recently in west and Kellem Wollega zones. The information of agronomic practices such as row and planting spacing is limited because it is produced at subsistence level by rural farmers and the farmer cultivate ground nut without consideration of the appropriate row and plant spacing. Research on manipulating plant density and their effects on growth and yield