INTRODUCTION

Garlic (Allium sativum L.), the second most important Allium crop after the bulb onion, is cultivated worldwide including Ethiopia and consumed by almost every culture as a popular condiment and green vegetable and is also used for its medical values (Kamenetsky, 2007;Jung et al., 2020). About 196 thousand tons of garlic is produced in Ethiopia (CSA, 2019) on 21 thousand hectares of land involving 1.95 million small-scale farmers in the highlands of the country. Most of the farmers produce garlic mainly to sale and earn cash while retaining a small amount for own consumption and for planting material. Moreover, a significant number of Ethiopians earn their living from involvement in production, transportation and marketing of garlic.

Despite its importance, the productivity of local cultivars of garlic is low 7.5 t/ha compared to the world average of 16.9 t/ha (FAOSTAT, 2018). The cultivars have as many as 20, but small size cloves which are difficult to process even for household uses. Moreover, the local garlic genotypes are susceptible to major garlic diseases such as garlic rust (Puccinia alli Rudolphi), downy mildew (Peronospora destructor Berk. Casp.), basal rot (Fusarium oxysporum), and an insect pest onion thrips (Thrips tabaci Lind.) further reducing productivity and production (Getachew et al., 2008;Abraham et al., 2019).

As a result, the price of garlic has been increasing sharply tripling within the past five years. Thus, introduction of genotypes and varieties from major garlic producing countries and testing their adaptability to Ethiopian conditions became of paramount importance. In previous report (Do et al., 2020), better growth and quality results were obtained in Korean peppers compared to local varieties.

Attempts have been underway to improve the productivity of garlic through the Technical Cooperation Project (TCP) in collaboration with the Korea Program for International Cooperation in Agricultural Technology (KOPIA). The project “Development of improved garlic (Allium sativum L) technologies in Ethiopia” has been undertaken since 2014. Among other efforts, the project introduced thirteen garlic genotypes from the Republic of Korea. The objective of the present study was, therefore, to investigate the performance and adaptation of some introduced garlic genotypes, mainly of Namdo, in Ethiopia.

MATERIALS AND METHODS

The thirteen garlic genotypes were introduced from the National Institute of Horticulture and Herbal Science (NIHHS), Rural Development Administration (RDA), Republic of Korea in 2013. The introduced varieties were: Namdo, Daeseo, Dasan, Hwasan, Sandae, Poongson, Ui seang (bulbils), Wangyo 57025, Wangyo 57030, Wangyo 57031, Wangyo 57028, Wangyo 57022, and Wangyo 57024. A preliminary (observation) study was conducted to test the adaptability of the genotypes.

They were planted at Debre Zeit and Kulumsa Agricultural Research Centers in the rainy season of 2014. The regional characteristics of two experimental cites were as below (Table 1).

Each genotype was planted on a single ridge comprising of 20 plants. The released local variety Kuriftu was also planted for comparison. Data on vegetative as well as bulb yield and yield components were recorded and analyzed using descriptive statistics.

In addition, the performance of Namdo was further compared with four local varieties (Tsedey, Holeta Local, G- 94-1/94, and G-104-1/94) developed by the Debre Zeit Agricultural Research Center. The trial was undertaken at Kulummsa Agricultural Research Center. The trial was laid out in randomized complete block design with three replications. Each variety was planted on a plot size of 4 m². Data on vegetative, bulb yield and yield components as well as days to maturity were recorded.

Analysis of variance (ANOVA) was undertaken using SAS statistical software (SAS Institute Inc., 1990). When the ANOVA was significant (p≤0.05), means were separated using Least Significant Difference (LSD) at 5 percent level of probability. All agronomic practices were undertaken as recommended by Getachew et al. (2008).

RESULTS AND DISCUSSION

The results of the preliminary study showed that only three of the thirteen genotypes Namdo, Daeseo, and Wangyo 57022 formed bulbs. The other ten genotypes failed to form bulbs irrespective of the long growth period they had taken in the field. In line with the present study, Moustafa et al. (2009) who compared nine introduced and five Egyptian garlic genotypes found out that three genotypes (Mild French, Asian Tempest, and Silver White) that belonged to silver skin and Asiatic groups failed to form bulbs in Egypt. Comparison of the genotypes that produced bulbs showed that Namdo had bulbs 38 to 60 mm in diameter and weighed from 25.1 to 92.7 g (Table 2). The bulbs comprised of 6 to 11 cloves that had 15.3 to 23.2 mm diameter and weighed 3.3 to 10.2 g.

On the other hand, Daeseo had smaller size bulbs than Namdo, but Daeseo bulbs had more number of cloves than Namdo, ranging from 8 to 16 depending on bulb size. In general, Namdo and Daeseo had considerably bigger bulbs than Kuriftu, the local variety. Both genotypes had bulbs more than double the bulb size of Kuriftu, whereas the weight of cloves of both genotypes are nearly five times the cloves of Kuriftu. In contrast, both Namdo and Daeseo took 179 days to mature as compared to the 120 days needed for Ethiopia varieties to mature, which is an additional 59 days.

The extended days to maturity of these varieties could be due to the short day photoperiod of the tropical environment they were subjected to in contrast to the temperate environment they were adapted. Atif et al. (2019) reported that shortening daily photoperiod from 16 h to 8 h extended days to maturity of garlic from 66 to 92 days.

Garlic grown at Kulumsa produced bigger cloves than those grown at Debre Zeit and matured ten days later than those grown at Debre Zeit which could be due to the fact that Kulumsa is a highland site with cooler temperature than Debre Zeit and is more suitable for garlic growth and development.

Results of a follow-up study undertaken at Kulumsa showed that Tsedey had the highest yield (128.7 t/ha) followed by Namdo (95.3 t/ha) and other varieties (P<0.05) (Table 3). Namdo was vegetatively vigorous than all the local varieties (P<0.05). It had the same bulb yield as Kuriftu and G-94-1/94, but significantly better than G- 104-1/94. The bulb weight of Namdo was not statistically significant compared to other varieties, except for G-104- 1/94 (P<0.05). Namdo had significantly low number of cloves (9) compared to fourteen in G-94-1/94 and twentythree in Tseday (P<0.05), which is 50 to 160% more than that of Namdo. However, the cloves of Namdo weighed three to six folds heavier than that of the other varieties (P<0.05), which was attributed to 54-67% thicker and 7- 30% taller cloves compared to its comparators, respectively (P<0.05).

Moustefa et al. (2009) evaluated fourteen genotypes and found that the number of cloves ranged from 8-43. Concurrently, Namdo and Deoseo had similar number of cloves as White Brazilian (8) and Inchelium Red (6), while the Ethiopian varieties had similar number of cloves as that of California Early (27) and Early Red Italian (11). On the other hand, some Egyptian genotypes such as Balady had 43 cloves.

The bulb weight of the genotypes tested by Moustafa et al. (2009) ranged from 67-173 g in sharp contrast to 33- 45 g observed in genotypes tested in the present study. Similarly, Kumar et al. (2015) studied 41 garlic genotypes in India and found genotypes with varying bulb weight (8.5-43.4 g), bulb diameter (2.3-4.4 cm), clove weight (7.8-30.5 g), and bulb yields (3.7-12.3 t/ha). Twenty-two percent of these genotypes had bulbils. In Ethiopia, bigger bulbs usually have bigger cloves and are preferred for ease of peeling and thus have better price than the small bulbs. However, there is no set prices based on size. It is subjective depending on how the merchants set and consumers accept the price. Very small bulbs are definitely not liked.

Namdo planted at three different dates had significantly different vigor of plants, bulb yield and yield components, and maturity date (Table 4). There are no differences in plant height, bulb diameter, and number of cloves per bulb among the planting dates, respectively. Namdo planted in mid-July produced the most vigorous plants that gave higher bulb yield as compared to later plantings (P<0.05). The vigorous plants resulted in heavier bulbs which could be due to taller bulbs. Moreover, those planted in mid-July had 16% thicker (P<0.05), 25% taller (P<0.05), and 31% heavier (P<0.05) cloves than those planted in mid-August and 46% thicker, 32% taller and almost twice heavier cloves than those planted in mid-September (P<0.05), respectively.

On the other hand, Namdo planted at three different months from mid-July to mid-September differed in their ability to produce top bulbils (Table 5). Thirteen percent of those planted in mid-July and mid-August produced top bulbils, while only 3% of those planted in mid-September produced bulbils (Table 5). Those planted in mid-August produced about 3.5 bulbils per plant each of which weighed 6.2 g while those planted in mid-July had only 2.2 bulbils per plant each of which weighed 3.0 g. The bulbils of those planted in mid-September were the lightest in weight (0.8 g). The bulbils produced viable seedlings (Fig. 2a, b).

SUMMARY AND RECOMMENDATIONS

Garlic production and productivity has been low, among others causes, due to lack of productive varieties and narrow genetic base of garlic from which development of elite varieties difficult. Thus, thirteen garlic genotypes were introduced from NIHHS. The genotypes were tested for their adaptability to agro-ecologies where garlic is grown in Ethiopia. An observation trial was undertaken at Debre Zeit, in 2014 rainy season comprising the thirteen genotypes and the local variety, Kuriftu. Only three of the genotypes could able form bulbs. The bulbs of these genotypes had fewer number of cloves but bigger in size than those of Kuriftu. However, they took about 179 days to mature as opposed to the 120 days taken by Kuriftu. Additional trial comparing Namdo, one of the best performing genotypes, with four other local varieties was undertaken at Kulumsa in the 2019 rainy season. The results showed where Namdo, had better bulb yield than all the varieties except from Tsedey. It had bigger bulbs and cloves than all the local varieties. However, it took longer time to mature than the local varieties. In addition, a planting date trial was undertaken to identify a suitable period for growth and development of Namdo at Kulumsa. Planting was done on mid- of July, August, and September. It was observed that Namdo planted in mid-July had better yield and bigger cloves than those planed on other dates. Moreover, those planted on mid-July and mid-August gave many plants with bulbils and bigger size bulbils than those planted in mid-September. Therefore, based on the results of the aforementioned studies, Namdo can be recommended for verification that may lead to its production in Ethiopia. However, the long period of time it takes to mature should be managed with further manipulation of planting date and supplemental irrigation in order to extend the growth period. Frailer of the ten genotypes to form bulbs indicated that genotypes adapted to temperate agro-ecology may not adapt to tropical agro-ecologies due to their difference in photoperiod requirement. Thus, large scale introduction and production for garlic prior to undertaking through investigation of the genotypes should be avoided.

적 요

마늘은 에티오피아에서 양념으로 쓰이는 가장 중요한 작목 중 하나이다. 그럼에도 생산성은 세계 평균의 절반 수준에 머 물고 있는 실정이다. 이렇게 생산성이 낮은 주요 원인으로는 품종의 다양성 부족, 낮은 영농기술 수준과 병해충 등을 들 수 있겠다. 이를 극복하기 위하여 한국의 농촌진흥청 국립원 예특작과학원으로부터 13종류의 마늘 품종이 도입되어 데브라 자이트와 쿨룸사에 위치한 농업연구소(Debre Zeit and Kulumsa agricultural research centers)에서 예비 실험이 진행 되었다. 도입된 13 품종 중에서 Namdo, Daeseo 및 Wangyo 57022 등 3 품종에서만 주아 (bulbil)가 형성이 되었다.

한국에서 도입된 마늘 3 품종의 적응성을 조사한 결과는 아 래와 같이 정리할 수 있다.

한국에서 도입된 품종 중에서 특히, Namdo의 경우 성장 기 간이 조금 떠 짧아질 수 있다면 에티오피아에서 생산이 가능 한 품종으로 판단된다.