1Ethiopian Institute of Agricultural Research, Jimma Agricultural Research Center, Ethiopia
2Jimma University College of Agriculture and Veterinary Medicine, Ethiopia
Received: January 07, 2021; Accepted: January 21, 2021; Published: February 02, 2021
Citation: AbaDura NS, Beyene TM, Garadew W (2021) Genetic Diversity of Enset ( Ensete Ventricosum (Weelw)) from Southern Ethiopia using Morphological Traits. J Plant Sci Agri Res Vol.5 No.1:48.
South and Southwestern part of Ethiopia is repository for indigenous crop ‘ensete ventricosum. To assess the diversity of these clones, study was carried out in Southern part Sheka zone, Ethiopia. The altitude of the study area ranged from lowland to highland. The study was conducted on-farm within these three agro-ecologies viz., lowland (Yeki), Midlan (Andiracha) and highland (Masha). The result indicated that there were significant variations among genotypes in few qualitative traits (psedostem and most quantitative traits. Moderate variations were observed among enset clones in pseudostem and midrib color with evenness (E) values of 0.59 and 0.54 respectively. Besides, the enset in the study area differ in stature ranging from minimum of 2 m to maximum of 7m, leaf length (2.00-6.80 m), leaf width (0.4-0.98cm) and psedustem circumference (1.00-2.90m). The altitudinal effects on growth of enset were observed where the maximum growth parameters diversified enset clones were recorded at higher altitude and decreased with decrement of altitude indicating higher altitude to be conducive for enset productions and diverse enset genetic resources.
Diversity; Ensete; Quantitative Traits; Qualitative Traits
There are different root and tuber crops grown in Ethiopia at different agro-ecologies. These include potato, sweet potato, taro, yam, cassava, anchote and Ensete are some of them. Each of them grows at different altitudinal range from lowland to highland of these crops; potato and Ensete are categorized under highland crop even though it can be grown at mid-altitude. Among these crops, Ensete and anchote are indigenous to Ethiopia .
Despite Ensete grouped under root and tuber crops, unlike other root and tuber crops, its corm and pseudo-stem are consumable part while all the rest parts are functional for multipurpose including construction materials, wrapping purpose, animal feed, medicinal value and etc. . Mostly it is source of carbohydrate with low protein where producers supplement with other pulse crop to fill protein gap . The crop is important food crop after cereal and pulse with coverage of 25% of arable land in southern region of Ethiopia supporting more than 6-7 persons per house .
In Ensete producing areas, there are diversified Ensete landraces cultivated where farmers plant separately for different purpose. These clones indigenously identified based on farmers experiences. Additionally, number of researchers conducted on-farm diversity study as well as compositional analysis and reported as there is diversity among assessed clones. For example, Tesfaye and Ludders  conducted on-farm diversity study and recorded about 86 named landraces. Similarly, Zerihun  in his survey study undertaken in eight zones of SNNPR of Ethiopia that 218 different Enset clones were recorded with their vernacular name; the survey result conducted in Kembata Tembaro zone by Melesse , detected Ensete clones diversity and the uses of clones were portrayed where total of 111 different Ensete clones were characterized by farmers, of which 21 of them have medicinal uses. Additionally, Semman  conducted survey study in Sheka zone and identified 90 Ensete clones based on farmer’s morphological classification methods like leaf, midrib and pseudo-stem color. Besides, the Semman  assessed biochemical content of 14 Enset clones and clustered under three groups. However, most studies done at different Ensete growing region consider phenotypic and farmer’s classification and naming based. To verify the extent and reality of the diversity of the crop in the specific study area or to disqualify it, measuring and recording quantitative and qualitative traits of the crop is the base as benchmark and as a source of information to conserve and conduct further experiment on this indigenous crop. That was why this experiment was conducted to quantify the extent of Ensete clones diversity based on quantitative and qualitative parameters in Sheka zone, southern Ethiopia.
Description of the study area
The study was conducted in Enset repository zone Sheka zone within three districts i.e. Masha, Yeki and Andiracha which found in South Nation Nationality People Regional State (SNNPRS) south part of Ethiopia. The zone has three agro-ecologies (lowland, midland and highland) laying between 7024’N-7052’N of latitude and 35°13’E-35°35’E longitude at an altitude ranging from 900 MASL-2800 MASL . Agro-ecologically, Masha is found at highland agro-ecology at altitudinal range from 1800 MASL-2800 MASL. Andaracha is also located from mid to highland altitudinal range from 1400 MASL-2500 MASL whereas Yeki which is low to midland of 900MASL-1800MASL. Generally, the zone receives minimum and maximum annual rainfall of 1600 mm-2200 mm and minimum and maximum temperature of 21°C-29°C .
Quantitative traits such as Plant Height (PH), Leaf Length (LL), Pseudostem Circumference (PsCr), Leaf Width (LW) and Petiole Length (PetL) were recorded in meter from 43 different Enset clones sampling three plants from each clone and district that were mature enough and uniform age managements.
Additionally, qualitative attributes like leaf color, pseudostem color, petiole color and mid-rib color were collected using banana descriptor with some modification as used by other scholars.
All quantitative trait data were subjected to Analysis of Variance (ANOVA) and analyzed using nested design ( Enset clones were nested under each district) to investigate if significant differences exist among the locations using SAS Ver. 9.1.
To evaluate the Enset clones diversity, abundance, distributions, evenness and richness across the districts of Sheka zone, Simpsons’ (1949) and Shannon-Weaver (1949) diversity indices were calculated using the following formula. Shannon diversity index (H’) = −Σ pilnpi;where pi is proportional abundance of ith clone (ni/N), Simpson diversity index (S ) = (1− D) =1−Σn((n −1) / N(N −1))2 and D = −Σ(n / N)2, where D denoted for measure of probability that two individuals randomly selected from the same site, N=total number of farm surveyed or Enset producers or total number of individual clones, ni= is frequency of ith species.
Qualitative and Quantitative Traits Based Enset Diversity
Qualitative data based Enset clones diversity
Analysis of Shannon-Weaver diversity index (H’) of four morphological qualitative traits of 43 Enset clones was evaluated and presented in Table 1. The analysis of qualitative data for pseudostem color indicated, most numbers of clones had showed dark brown pseudostem color with 23.25% followed by greenish black leaf sheath with 16.27% and 13.95% respectively. The minimum diversified species were Enset with black spot on green (2.33%) and dark red to greenish yellow pseudostem color with 4.65% each Table 1.
Table 1: Frequency distribution and Shannon-Weaver diversity indices (H’) of qualitative traits.
|Traits||Code||Description||Frequency of clones||%||E=H’/H’max|
|Pseudostem color||1||Dark red to black||2||4.65||0.59|
|2||Dark red to brown||4||9.3|
|3||Black spot on green||1||2.33|
|Leaf color||1||Light green||6||13.95||0.34|
|4||Middle black with either side green||2||4.65|
|5||Green with black stripe||7||16.28|
|9||Red with black stripe||1||2.33|
|Midrib color||1||Greenish red||9||20.93||0. 47|
|7||light red to red||2||4.65|
|Mean||0.50 ± 0.1|
Regarding leaf color, clones were predominantly deep green and dark green color with 39.53% and 37.21% respectively. Besides, though light greenish leaf cultivars were more about 13.95%, there were few clones with light-purple and purple color with 4.65% each respectively Table 1.
As far as petiole and leaf mid-rib color concerned, majority of clones were black (25.58%) and dark red with 18.60% petiole color and red (27.90%) and greenish red (20.93%) mid-rib color recorded. But, cultivars with purple and red with black stripe petiole color were few in numbers with 2.33% only. In the case of mid-rib color few clones with light red to red and purple midrib color (4.65%) were recorded. The same report was cited by Zerihun  in which frequency of petiole and mid-rib red color with red ranged second next to green color.
Additionally, evenness result also revealed moderate diversity index value for pseudostem (0.58) and petiole underside color 0.54, and minimum for leaf and mid-rib color each 0.47 and 0.34 respectively Table 1. Likewise, Mikias  recorded minimum and maximum Enset diversity index from 0.31 to 0.95 for leaf color and mid-rib color. Also, 0.94 for petiole underside as well as 0.83 for mid-rib underside color were reported. The mean ± Standard value of all traits in this analysis was 0.48 ± 0.1 detecting as there was minimum morphological evenness within the clones detecting variation of clones Table 1.
This was supported by classification of Shannon Weaver Diversity index (H’) as high when E>=0.75, moderate when E=0.5-0.75 and low when E<0.5 by Jamago . The qualitative morphological result Table 1 witnessed the view of farmers on identification of clones based on color of different plant parts.
These morphological variations of the clones provide an opportunity for improvement through breeding the crop and call for germplasm conservation .
Analysis of variance of quantitative trait based Enset clones diversity
The analysis of variance for Enset quantitative traits showed there were significant differences among Enset within the districts with all analyzed parameters except leaf width Table 2.
Table2. The summary of ANOVA for traits and their significance level for 43 Enset clones.
|Traits||Mean square||CV (%)||Mean ± SD||Min||Max|
|PH (m)||7.07||1.47||0.43||14.16||4.51 ± 1.19||2.00||7.20|
|LL (m)||0.81||0.96||0.17||10.00||4.40 ± 0.92||2.00||6.80|
|PsCr (m)||0.47||0.25||0.20||10.72||1.88 ± 0.44||1.00||2.90|
|LW (m)||31.59||182.71||140.70||15.72||0.75 ± 0.14||0.40||0.98|
|PetL (cm)||23.13||19.94||8.591||3.35||0.28 ± 0.13||0.00||0.60|
PH:Plant Height, LL: Leaf Length, PsCr: Pseudostem Circumference, LW: Leaf Width, PetL: Petiole Length
The mean, minimum, maximum, root mean square of clones and coefficient of variation of all parameter were summarized in Table 2. Accordingly, maximum Plant Height (PH), Leaf Length (LL), Pseudostem Circumference (PsCr), Leaf Width (LW) and Petiole Length (PetL) were observed to be 7.2 m, 6.80 m, 2.90 m, 0.980 m and 0.60 m respectively. The minimum were recorded to be 2 m, 2 m, 1 m, 0.4 m and 0 m for plant height, leaf length, pseudostem circumference, leaf width and petiole length with mean of 4.1 m, 3.60 m, 1.68 m, 0.75 m and 0.25 m in that order.
Concerning the location effects, the mean separation result revealed that there was highly significance differences observed between all districts for plant height and pseudostem circumference Table 2. From the result one can understand that, even though clones nested under districts (wereda), as altitude of the area increase, all parameters of Enset increase. The largest plant height, leaf length and pseudostem were found in Masha than Andiracha and in Andiracha than Yeki based on altitudinal variation.
But, there were no significant difference among the three districts with leaf width and petiole length. For leaf length, there is no significance difference observed between Andiracha and Masha but, there was difference between Andiracha and Yeki as well as Masha and Yeki districts Table 3. This might be due to agroecological variations where Masha and Andracha mainly highland areas while Yeki altitudinal range are low to midland.
Table3. Summary of mean separation of districts on quantitative traits of 43 Enset clones
|Districts||Plant height||Leaf length||Pseudostem circumference||Leaf width||Petiole length|
The result of the study for both quantitative and qualitative attributes indicated that, there were variations among Enset clones. However, the extent of variation for different traits varies. Concerning qualitative trait, most Enset moderately vary in pseudostem and petiole color. Additionally, the quantitative trait measurements indicated difference among available Enset clones in most attributes except in leaf width and petile length. However, for more confirmation and thereby to conserve each Enset indigenous genetic resources separately, molecular characterization is very important.