Journal of Natural Sciences Research www.iiste.org ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online) Vol.5, No.5, 2015 1 Effect of Inter and Intra-Row Spacing on Yield and Yield Components of Tomato (Solanum lycopersicum Linn.) in South Tigray, Ethiopia Harnet Abrha 1 Abrha Kebede 2 Birhanu Amare 1 Mehari Desta 1 1.Tigray Agricultural Research Institute, Alamata Agricultural Research Center, P.O.Box56 Alamata, Ethiopia 2.Hawzen Millennium Village Project, Hawzen, Ethiopia Corresponding author E-mail: hany7mn@gmail.com Abstract Tomato is one of the vegetables with its highest production in south Tigray and growers used as a source of income due to its cash value nature. A field experiment was conducted at Tumuga and Fala locations during 2012/2013 cropping season under irrigation condition. The objective was to determine the best inter and intra- row spacing for optimum yield and yield components of tomato. The treatment consisted of factorial combination of two inter-row spacings (50 and 100 cm) and three intra-row spacings (20 cm, 30 cm and 40cm) using Randomized Complete Block Design in a factorial arrangement(2x3) with three replications. The highest total and marketable fruit yield was obtained from 20 cm intra-row spacing with 50 cm inter row spacing. On the other hand, the lowest total and marketable fruit yield was obtained from the wider spacing of 40 cm intra-row with 100 cm inter-row spacing. The present result indicates that determinate tomato type can produce higher total and marketable fruit yield under narrowly spaced plants. From this study it could be concluded that appropriate inter and intra-row spacing with variety selection could be practiced to increase the yield and quality of tomato plant. Thus, Tomato (Roma VF variety) growers around the study area can be benefited if they use narrow spacing (20 cm intra and with 50 cm inter-row spacing). Keywords: Tomato, intra-row spacing, inter-row spacing, yield INTRODUCTION Tomato (Solanum lycopersicum Linn.) belongs to the Solanaceae family. The center of origin for the world tomato is considered to be Andean zone, whereas it is considered that the tomato was domesticated in Mexico, and that the name of tomato was derived from the ‘tomatil’ in the Nahua tongue of Mexico (Ara et al., 2007). Presently, tomato is one of the vegetables with the highest production in the world and its production is increasing all over the world, primarily, in Asia. The production area in Europe, north and Latin America tends to stop increasing but the production is sustained by the increase of yield per hectare, probably using high yielding varieties and other improved agronomic practices (Zhang, 2010). The importance of tomato as a vegetable crop is reflected in its large-scale cultivation in the world. Tomato is grown on about 4.5 million hectares worldwide, the largest producer being China with 32 million metric tons. India produces about 7.6 million metric tons of tomatoes from about 540,000 ha (Daniel, 2007). Now-a-days tomato is grown in most of the countries around the globe except the colder region. It can be grown on a small scale in the kitchen garden, where a few plants yielding fruits for the whole family and a commercial scale as a cash crop by the vegetable growers (David, 2010). Tomato is among the most important vegetable crops in Ethiopia. Both fresh and processed tomato varieties are popular and economically important vegetable crops produced in the country (Geleta et al., 1995). The total production of this crop in the country has shown a marked increase (Lemma et al., 2003) since it became the most profitable crop providing a higher income to small scale farmers compared to other vegetable crops. However, tomato production is highly constrained by several factors especially in developing nations like Ethiopia. The national average of tomato fruit yield under farmers’ condition is 9 t/ha, which is very low compared to 25 and 40 t/ha at demonstration and experimental research plots, respectively (Lemma, 2002). Increasing production of the crop has a great role to strengthen the growing vegetable industries in the country. However, the production and productivity of the crop in the country is influenced by different factors. Lemma et al. (2003) reported that plant spacing greatly influenced fruit yield in both fresh market and processing tomatoes. Mehla et al. (2000) also reported the importance of plant spacing on yield and quality parameters in tomato crop in addition yield variation in tomato may also be occurred due to disease infestation, lack of improved variety and variation in cultural practices like plant population per given area. Plant spacing is the most important factor that affects yield and fruit quality of tomato (Tesfaye, 2008). In Ethiopia, so far plant spacing was determined for tomatoes only at Melkassa research center, moreover, such study was done in tomatoes under vertisol condition and the whole of such previous agronomic studies were confined only to sandy loam soils of the rift valley regions of the country. Accordingly, farmers get lower yield