Project Abstract

<p>&nbsp;             <b>ABSTRACT&nbsp;</b></p><p>Garlic (Allium sativum L.) is one of the most important vegetable crops produced in Tigray region; however, farmers are producing the crop from the available cultivars without or with very low rates of nitrogen fertilizer. The cultivars produced in the region were not evaluated in comparison to improved varieties to the response of nitrogen fertilizer. Therefore, this experiment was conducted during 2014/2015 in Gantaafeshum district in Tigray region with objectives of assessing the effect of nitrogen rates on yield and yield related traits of garlic cultivars and thereby identifying adaptable and high yielding cultivars with higher market demand. Seven garlic cultivars (three improved, three locally introduced and one local) and four N fertilizer rates (0, 41, 82, 123 kg N ha-1 ) were arranged as 7 x 4 factorial treatments and laid out as a randomized complete block design with three replications. All yield and yield related traits were significantly influenced by the interaction of cultivar and nitrogen fertilizer except leaf length (cm), leaf number per plant, bulb length (cm) and sizes of bulbs and cloves of different categories that were significantly influenced either by both cultivar and nitrogen or one of these. The highest total yield was obtained from the cultivar Bora 1 (12.61 t ha-1 ) at the rate of 82 kg N ha-1 but the yield decreased to 12.27t ha-1 as the nitrogen level increased to 123 kg N ha-1 . The lowest yield was recorded from the local cultivar Guahgot (5.31 t ha-1 ) without N fertilizer application. The quality was determined based on number of marketable bulbs and weight of cloves.Bora-1 had 44.44 and 20% of bulbs categorized under medium and large categories, respectively. This cultivar had also the highest proportion of marketable cloves categorized under medium (27.10%) and large (33.80%) clove categories. The cost benefit analysis indicated that cultivar Felegdaero followed by Bora 1 both at 41kg N ha-1 rates had maximum marginal economic return of 148.24 and 135.84, respectively. Therefore, it is possible to suggest the advantage of growing cultivar Bora-1 at 82 kg N ha-1 followed by Tsedey and Felegdaero varieties both in combination of 123 kg N ha-1 at Guahgot, Gantaafeshum district and in other areas having similar agro-ecology. Key words Bulb yield, garlic variety, local cultivar and nitrogen <br></p>

Project Overview

<p> 1. INTRODUCTION&nbsp;</p><p>Garlic (Allium sativum L.) belongs to Alliaceae family (Allen, 2009). The origin of garlic is thought to be in Central Asia (India, Afghanistan, West China, Russia) and spread to other parts of the world through trade and colonization (Tindal, 1986). Garlic has been used in China and India for more than 5000 years, and Egypt since 2000 B.C. (Kamenetsky and Rabinowitch, 2001). Garlic is the most important Allium crop and ranks second next to onion in the world (Voigt, 2004). With respect to its production and economic value, garlic is one of the main Allium vegetable crops in the world and used as a seasoning in many foods throughout the globe. The oil of garlic is volatile and has sulfur combining compounds which is responsible for strong odor, its unique flavor and pungency as well as for healthful benefits (Salomon, 2002). Garlic is a basic flavoring in many types of dishes ranging from vegetable soup, meat, salad, tomato combination, spaghetti, sausages and pickles (Brewster, 1994). Similar to green onions, it is eaten as green and blenched tops in different ways as fresh and cooked as well as immature bulb consumption is common especially in tropics (Rabinowitch and Brewster, 1990). Bread and butter obtained from garlic have many uses in homes and restaurant cooking and food preparations (Nonnecke, 1989). Garlic has also medicinal value which is well recognized in the control and treatment of hypertension, worms, germs, bacterial and fungal diseases, diabetes, cancer, ulcer, rheumatism etc. (Kilgori et al., 2007(b); Samavatean et al., 2011). Many people perceived and appreciated garlic for its many medicinal attributes (Rabinowitch and Currah, 2002). The plant can perform best when planted on well drained soils. It is better to plant on flat beds; but on heavy soils, which are poorly drained during the rains; it is advisable to plant on the ridges. To obtain good yield, producers should give attention to select a land which has high fertility and apply considerable quantities of manure or fertilizers. Garlic production requires a growing period of 4.5-6 months and the amount of rainfall ranges between 600 mm to 700 mm during its production season. The optimum temperature for garlic growing lies between 12 °C and 24 °C. Garlic withstands moderate frost. Garlic production spread throughout the country and has been cultivated under irrigated as well as rain fed conditions, mainly in the mid and highlands of Ethiopia (Lemma and Hearth, 1994). <br></p><p> Garlic is one of the most important vegetable crops in Ethiopia and is used as ingredient of local stew ‘wot’ and has also a tremendous use in the formulation of local medicines. According to CSA (2012), in Ethiopia, garlic was cultivated on 13278.55 hectares of land and above 1.2 million quintal of yield was harvested during 2011/12 crop season. The average yield per hectare was 9.34 ton. Garlic is one of the most important bulb crops produced by small and commercial growers for both local use and export (Metasebia and Shimelis, 1998). As a cash crop, it is used to earn foreign currency by exporting to Europe, the Middle East, Africa countries and USA (Kilgori et al., 2007). At off season the same quantity of garlic is usually sold at twice or three times the value of onion (Getachew and Asfaw, 2000). In Tigray, producing and marketing high value vegetable crops are intensifying throughout the region. Different vegetables and spices have been introduced and cultivated mostly in the lowlands or flood plains where source of water and soil fertility is relatively higher. Garlic is one of the high value vegetable crops produced during the cold season, in rotation with pulses that have contributed in breaking the life cycle of pest problems and improve soil fertility (Gebremedhin et al., 2010). In the year 2011/2012 production season, the area covered by garlic production was about 616.10 ha; the total production obtained from this hectare was 8891.8 tones (CSA, 2012). <br></p><p> In spite of its importance (increasing of garlic production and productivity), garlic yield is low in many parts of the world, due to genetic and environmental factors affecting its yield and yield related traits (Nonnecke, 1989). In many garlic producing areas, lack of available nutrients is frequently the limiting factor next to soil water, because the uptake and liberation of N, P and S from soil organic matter depends upon availability of water (FAO, 2003). The other production constraints of garlic include lack of improved varieties resistant to major diseases and insects (Getachew and Asfaw, 2000). To overcome such production problems, great effort should have to be made in the selection and breeding of high yielding cultivars and the development of cultural techniques (Rabinowitch and Brewster, 1990. The most constraint of garlic production and productivity of the country in general and of the study area in particular is lack of improved variety (ies) in required quality and quantity. Consequently, farmers are restricted to use garlic landraces inferior in yield, prone to most of the diseases and insects with traditional agronomic practices. However, it is supposed that not all local cultivars are inferior in yield and quality. But less attention has been given to evaluate the local cultivars along with the improved varieties. Mostly farmers in Tigray region are using very low fertilizer rate below blanket recommendation. Because, it is not known the optimum rate of N and apply very small amount which could not have significant function for the crop production. Therefore, the low yield in the region is expected to be the results of lack of improved and adopted garlic varieties as well as the low N-fertilizer rates application. To overcome this problem, it is necessary to introduce improved garlic varieties and agronomic practices in the area which requires testing and identifying of suitable technologies before making recommendation. <br></p><p> A study in the Central Ethiopia indicated that application of 92 kg N ha-1 , 40 kg P ha-1 , and 30 kg S ha-1 was appropriate to attain maximum quality of the crop for enhanced household income (Diriba et al., 2013). It was also reported that garlic bulbs supplied with N, P and S improve bulb quality and nutrient contents did not significantly respond to highest level of phosphorus for bulb yield. Nitrogen and sulphur application showed a direct and positive effect on pungency and total soluble sugar (TSS) content. This showed that the importance conducting research focusing on N rates to increase yield which is partly the extension of the previous study. On the other hand, it is necessary to test different varieties and farmers cultivars with different N rates to identify variety (ies) and/or local cultivar(s) to attain maximum garlic yield potential for the specific agro-ecology. This is because that the varieties and agronomic practices recommended elsewhere may not perform in the new areas due to agro-ecology and genotype by environment interaction differences. Therefore, this&nbsp; study was initiated with the general objective of selecting high yielding and adaptable garlic cultivars with optimum nitrogen level to be applied in the study area.&nbsp;</p><p><b>Specific Objectives:&nbsp;</b></p><p>1. To identify adaptable and high yielding garlic varieties/cultivars with higher market demand for the study area 2. To elucidate response of garlic varieties/cultivars to nitrogen rates on growth, yield and yield components of garlic <br></p>