Research Article
Performance of Some Ethiopian Fenugreek (Trigonella foenum-graecum L.) Germplasm Collections as Compared with the Commercial Variety Challa
School of Plant Sciences, Haramaya University, P.O. Box 138, Dire Dawa, Ethiopia
The grain legumes not only provide variety to human diet but also supply dietary proteins for vegetarians that abstain animal and fish proteins in their diet. Furthermore, considering the rapidly growing human population and thus the problem of malnutrition especially in Sub-Saharan Africa, use of legume species as a source of high-protein food is an amicable option. Moreover, legumes are also capable of symbiotic nitrogen fixation and thereby enriching the soil conditions that become suitable for crops following those (Bromfeild et al., 2001).
The genus Trigonella is one of the largest genera of the tribe Trifoliate in the family Fabaceae and sub-family Papilionaceae (Balodi and Rao, 1991). Among Trigonella species, Trigonella foenum-graecum (commonly known as fenugreek) is an annual species, with autogamous white flowers occasionally visited by insects. It is indigenous to countries on the eastern shores of the Mediterranean but widely cultivated in India, Egypt, Ethiopia, Morocco and occasionally in England (Polhill and Raven, 1981; Acharya et al., 2006). According to Hymowitz (1990), T. foenum-graecum, although important in food and medicine, is rarely grown outside its native habitat. Across the world only few known and well-defined cultivars are grown in specific areas.
Fenugreek is a chemurgic cash crop, usually cultivated as a break crop for cereal and it is considered as a good soil renovator (McCormick, 2004). The whole plant is used as forage and vegetable, while the seeds (whole, powdered into flour, or roasted) are used as human food and animal feed (Mir et al., 1993), spice, dyeing, flavouring, as well as for medical and (Westphal, 1974; Sharma et al., 1990) industrial purposes (Sharma et al., 1991). The aim of plant breeder is to develop improved varieties with increased yield and an acceptable grain quality and stability. This is the major breeding objective for fenugreek, as reported by Edison (1995) in countries such as India.
Systematic breeding efforts on this crop have so far been neglected and presence of variability in this crop offers much scope for its improvement. Only little of such vital information on fenugreek landraces is present under Ethiopian conditions. In view of filling up such a technical gap, this piece of research work was conceived by the author to address the objective of evaluating the potential of the land races as compared with the commercial variety for future improvement program.
Experimental site: The field experiment was conducted at Haramaya University Research station located at 9°24'N and 42°03'E, in Ethiopia during 2011 main cropping season. Haramaya has an altitude of 1980 m.a.s.l. It was in semi-arid sub-tropical belt of eastern Ethiopia. The area receives an average annual rainfall of 870 mm. The soil is characterized as a fluvisol with a pH of 7.4.
Experimental material and design: One hundred forty-three random samples of fenugreek accessions along with a commercial variety, Challa, were considered in this study. The accessions were collected from the most important production complexes of Ethiopia representing different agro-ecologies of varying altitude, rainfall, temperature and soil type (Fig. 1).
The commercial variety, Challa was released by Ethiopian Institute of Agricultural Research, Debrezeit Agricultural Research Center, after fulfilling the requirements set by the National Variety Release Committee for national production primarily in areas with 1700-2600 m.a.s.l. and average annual rainfall of 700-1200 mm. It is typically characterized by average seed yield of 900-1800 and 800-1500 kg ha-1 on research and farmer fields, respectively. The list of the tested accessions is given along with their geographical origins in Table 1.
Treatments were arranged in a 12x12 simple lattice design. Seeding was done in a plot of four rows with 2 m length and regular spacing of 10 cm between plants and 25 cm between rows. The layout and randomization were as per the standard procedure set by Cochran and Cox (1957). Two seeds per hole were placed carefully to ensure the first germination. Thinning was made at the true leaf stage. Weeding and other cultural practices were done as per the recommendations.
Data collected and analysis: The following data were collected during 2011 from the central two rows of the plot or from five sample plants randomly from each plot. Mean values of these samples were utilized to estimate the performance of each germplasm accession for the traits under consideration. The following data such as; days to flowering, days to maturity, grain filling period, powdery mildew, number of pods per plant, plant height, number of seeds per plant, number of seeds per pod, number of nodes per plant, number of podding nodes per plant, number of primary branches per plant, number of secondary branches per plant, number of nodules/plant, fresh weight of nodules/plant, number of effective nodules/plant, biomass yield per plot, thousand seed weight, seed colour, seed yield and harvest index were collected and subject to the analysis.
Fig. 1: | Map of Ethiopia showing geographical locations from where the accessions of fenugreek were collected |
Table 1: | Geographic origins of the fenugreek accessions by administrative zone, woreda and altitude |
NA: Not available, 1The second highest administrative level next to the region and accommodates from 15-20 Woredas, 2The next highest administrative level after zone and accommodates more than 20 peasant association | |
Least Significant Difference (LSD) was used for mean separation as indicated hereunder:
LSD = tα/2(Rdf)×SED
where, comparisons for two treatment mean:
And comparison of each treatment with grand mean (Singh and Chaudhary, 1999):
Whereas, a criterion that can be used to test whether each collected accession is significantly higher than a standard check (in this case Challa) was done by the LSI (Least Significance Increase) procedure which was the one-sided version of the LSD procedure which consisted of a series of one-tailed t-tests. The value of Least Significance Increase was tested at the 5% level of significance, by the formula as shown bellow as used as (Clewer and Scarisbrick, 2001):
where, Rdf is Residual degree of freedom; tα/2 is Tabulated value, SED is Standard error of deviation, EMS is Error mean square, r is number of replication and n is number of treatment.
As pointed out earlier, this investigation was conducted to bring to light the objectives of evaluate the potential of the land races as compared with the commercial variety and the detail accounts of each of these are presented and discussed hereunder in light of the available literature.
Comparisons made between the performance of the commercial variety Challa and the landraces is given in Table 2. There were many accessions that significantly differed from the commercial variety. Out of the traits considered in the experiment except thousand seed weigh, all showed significantly maximum value among the tested accessions (Table 2). When compared with the commercial variety, more than 31% of them in number of primary branch per plant, 27% in seed yield, 25% in physiological maturity, 14% in number of podding nodes per plant and about 8% in reaction with powdery mildew of the tested accessions performed significantly better in terms of the mentioned traits indicating that significant yield gains could be secured by simple selection. However, further evaluation over wider environments is necessary to arrive at conclusive points for such quantitative traits.
In contradict to this; there were accessions inferior to the commercial variety, Challa, in their performance. Of these, 66.43% of the tested accessions were susceptible to the disease powdery mildew more than the commercial Challa. And few of them showed inferior performance in thousand seed weight, number of nodes, secondary branch and total nodules per plant as compared with the commercial. Similar with the findings of other scholars like and this finding is in consistent with the finding of Asfaw et al. (2003), Feysal (2006), Banyai (1973) and Provorov et al. (1996).
Identification of superior accessions: The commercial variety, Challa with a value of 125 days ranked 4th for earliness in days to maturity, 59th for thousand seed weight (17.9 g), 58th for number of effective nodules per plant (2.55), 72nd for earliness in days to flowering (51 days), 122nd for biomass yield (2560 kg ha-1) and 131st for seed yield (920 kg ha-1). Traits of the ten highest ranked accessions for biomass and seed yield, days to maturity, number of podding nodes per plant, number of effective nodules per plant and thousand seed weight in comparison with those of the commercial variety Challa are presented in Appendix (Table A). The result from this investigation is in agreement with the previous reports of Cornish et al. (1983), Pant et al. (1983), Schneiter et al. (1994) and Feysal (2006).
The highest biomass yielding accessions were generally characterized by earliness in days to flowering but delayed in days to maturity implying that they need longer period for grain filling.
Table 2: | Number and proportion of germplasm collections exhibiting significantly lower or higher values of agronomic traits as compared with the commercial variety Challa |
They also had higher values of plant height, number of pods per plant, number of seeds per plant and pod, thousand seed weight, seed yield, number of nodes per plant, number of primary branches per plant and fresh weight of nodules per plant. The determining factor for biomass production in this study was plant height. Taller accessions produced more biomass. Heritability for plant height was high, despite the large environmental variance component (Fikreselassie et al., 2012). These accessions have equal values for harvest index, number of podding nodes per plant, secondary branches per plant and number of total and effective nodules per plant. Accessions in this category were yellow and green in seed color. Seven of them collected from North-western, one of each were from North-eastern and eastern part of the country. From the top ten of high seed bearing accessions, seven of the accessions had green and three had yellow seed color. In general, eight of the accessions were collected from North-western and one of each were from North-eastern and South-eastern Ethiopia.
Accessions producing the highest number of effective nodules per plant were characterized by shorter period of flowering and maturity. These accessions were superior for all of the nodulation traits (total and effective number and fresh weight of nodule). They however, categorized as equal for grain filling period, harvest index and number of seeds per pod. All of these accessions had green seed color except one accessions from South-eastern with yellow seed and one from North-western with mixed seed color.
Accessions producing the highest thousand seed weight, required longer periods to flower and mature and thus longer grain filling periods. They were also superior in number of secondary branches per plant. However, they were intermediate, for biomass and seed yield, harvest index, plant height, number of nodes and primary branches per plant, total and effective number of nodules per plant. Among the tested accessions, four of them (FgColl207599, FgColl234029, FgColl234026 and FgColl234033) exhibited white seed color, while four accessions (FgColl53107, FgColl236622, FgColl207370 and FgColl53014) exhibited yellow and the remaining two accessions (FgColl239061 and FgColl53005) exhibited green seed color.
Accessions, which reached physiological maturity in the shortest period, were also characterized by earlier days to flowering and shorter grain filling periods but higher number of seeds per pod and harvest index. This is in consistent with the findings of McCormick (2004). They were characterized by lower biomass and seed yields. Among the top ten early flowering and maturing accessions, eight of them had green seed color, whereas the remaining two were yellow. Four of the top ten were collected from North-eastern, two each from North-western and Eastern and one accession from South-eastern part of the country.
Accessions bearing higher (>30.7) number of podding nodes per plant were found to be late to flower and mature and thus had longer grain filling period and also had higher number of pods and seed yield and number of primary and secondary branches per plant. From the accessions with such characteristics, five had white, four yellow and one accession had green seed color. While seven of them were collected from north-eastern, the remaining three were collected from north-western Ethiopia.
From the present investigation, there is a possibility for selecting accessions with both high biomass and seed yield. For instance, FgColl212777 (5760 and 1440 kg ha-1), FgColl53078 (4600 and 1760 kg ha-1) and FgColl53107 (4880 and 1600 kg ha-1) collected from east Gojam, FgColl212656 (4480 and 1720 kg ha-1) from south Wello and FgColl53023 (4320 and 1640 kg ha-1) from north Shoa were best candidates for the traits. This indicates that simultaneous selection for both green manure and grain production is possible from this set of accessions. Another point of worth notice is that all these accessions have originated from the highlands ranging from 2510- 2690 m.a.s.l.
Differences among seed types: Table 3 summarizes the major characteristics of the 144 Ethiopian T. foenum-graecum landraces as they distributed over the four classes of seed color (green, mixed, white and yellow). The results reveal that most (91 = 63%) of the accessions exhibited Green (G) seed color and were collected from the main growing regions of the north-western (22%), north-eastern (32%), central (16%), south-eastern (13%) and eastern (15%) Ethiopia. These accessions exhibited a wide range of values particularly for days to flowering and maturity, biomass yield and thousand seed weight. Green-seeded accessions were most commonly characterized by early flowering and maturity time, low biomass yield and thousand seed weight.
The Mixed-seeded (M) accessions accounting for only 2.77% of the tested germplasm, were collected from North-western and South-eastern Ethiopia. These accessions were typically characterized by relatively late in maturity, higher seed and biomass yields per plant and intermediate seed size as was measured by thousand seed weight.
The White-seeded (W) accessions accounting for 9.72% of the tested material were exclusively collected from north-eastern Ethiopia. These white seeded accessions were generally characterized by being late in flowering and maturity, having higher thousand seed weight and moderate in biomass and low seed yield.
As with the green-seeded accessions, distribution of the yellow-seeded ones also found to represents the different regions of collection and accounted for 24.31% of the entire accessions used for the study. While more than half of the yellow seeded accessions were collected from north-western, one third was from south-eastern, two accessions each from central and eastern and only one accession was collected from north-eastern part of the country. The yellow-seeded accessions were generally early to flower but intermediate to mature and had higher seed and biomass yields.
It is evident from the result that more than half of the collections turned out to be green-seeded which, according to Duke et al. (1981), is the type preferred most in the north African markets. Taking into account, the wide distribution of such green-seeded accessions over the major growing regions of the country, it is possible to think of the market potential available for future exploitation of the genetic wealth. McCormick (2004) suggested that from 205 fenugreek accessions collected from different countries, green large-seeded accessions were mainly from Ethiopia and Egypt. But on the other hand, because of the growing demand for white seeded fenugreek across the world, enhancing the seed yield of white-seeded accessions of fenugreek warrants a great deal of attention of the researchers engaged in improving the crop.
Differences among regions of collection: Table 4 summarizes the agro-morphological attributes of the 144 T. foenum-graecum landraces studied as they grouped by the regions of collection. It is discernable from the results that the highest seed yield was not recorded from accessions originating from one region; instead, it was recorded from accessions originating from north-west (1324 kg ha-1), central highland (1232 kg ha-1) and south-eastern (1204 kg ha-1).
Table 3: | Main characteristics of the accessions of Ethiopian T. foenum-graecum belonging to different classes of seed color |
G: Green seed color; M: Mixed seed color; W: White seed color; Y: Yellow seed color, βNumber in parentheses show the number of accessions included in each of the regions represented as 1: North-western Ethiopia, 2: North-eastern Ethiopia, 3: Central Ethiopia, 4: South-eastern Ethiopia and, 5: Eastern Ethiopia and 6: Commercial variety |
Table 4: | Main characteristics of the 144 Ethiopian T. foenum-graecum accessions collected from major collection regions |
G: Green seed color; M: Mixed seed color; W: White seed color; Y: Yellow seed color, βNumber in parentheses show the number of accessions |
Accessions from the central highlands of Ethiopia were mainly green in seed color with relatively moderate thousand seed weight (16.82 g) and biomass yield (3168 kg ha-1). The accessions were relatively late in days to flower (52 days) and mature (129 days) as compared with the commercial variety Challa.
Germplasms from north-western Ethiopia were characterized by relatively high seed (1324 kg ha-1) and biomass (3516 kg ha-1) yields and thousand seed weight (18.68 g) and moderate days to flowering (51 days) and maturity (130 days). Of the four seed color types, green and yellow types were predominant.
Conversely, the accessions from north-eastern Ethiopian were late in days to flowering (52 days) but were early in terms of maturity (129 days) and exhibited low seed yield (1148 kg ha-1). Accessions from this region had predominantly green and white seed colors accompanied with moderate thousand seed weight (17.16 g). The white-seeded fenugreek accessions were not found in most of the regions except the North-eastern region represented in this investigation. Now-a-day, white and bold seeded fenugreek is highly demanded among the world consumers and exporters because of its attractive appearance as one of the quality parameters important in the business sector.
Accessions from south-eastern Ethiopia were found to be early to flower (50 days) and mature (129 days) with moderately high seed (1204 kg ha-1) but low biomass (2872 kg ha-1) yields and thousand seed weight (16.42 g). The seed color of the accessions collected from this region was green and yellow. Accessions from Eastern Ethiopia were, on the other hand, early to flower (50 days) and mature (129 days) with moderately high biomass yield (2936 kg ha-1) and thousand seed weight (16.70 g). Green seed color was predominant in the region. These range of regional variability in fenugreek is in consistent with different scholars engaged in different pulse crop species (Keneni et al., 2005a, b; Mussa et al., 2003; Alemayehu and Becker, 2002).
From the present investigation, higher seed yield bearing accessions were collected from north-west and central part of Ethiopia. For bold seeded accessions, eastern and north-western Ethiopia seem the preferred areas of collection. Beside the above traits of interest, accessions from Eastern part of the country were found to be earlier to flower and mature. Regarding the traits of seed color, the north-eastern region appeared as the only origin of white seeded cultivars used in this particular study. In the improvement point of view, this piece of information is critical for breeders who engage in improvement program in such away he/she can find the gene of interest from potential areas and can improve the crop as well as can converge or pool the gene for future use. The extent of variability also reported by other scholars (Acharya et al., 2006; Marzougui et al., 2007; Davoud et al., 2010) with the support of the present findings.
One hundred forty-three random samples of fenugreek accessions along with one commercial variety (Challa) were investigated in this study. The evaluation of 144 T. foenum-graecum indicated variation in yield, yield-associated traits and seed color. From this study, as the data suggest, there are better performing accessions than the currently growing accession Challa. The highest performing accessions were still quite diverse in other traits under study, indicating the potential for wider adaptation to different environments. Green-seeded accessions had greater proportion of high yielding accessions than yellow-seeded types. The highest biomass and seed yielding accessions were generally associated with the categories of yellow and green seed colors. The highest thousand seed weight-producing accessions, required longer time for flowering and maturity and grain filling period and white and yellow-seeded accessions were predominant. The varying characters of the superior accessions have implications for further work. Thus, the variation for the different characters found in fenugreek accessions included in this study could be exploited and used in fenugreek breeding programs. Among the three different types of seed color investigated, which was green, yellow and white, the white seeded fenugreek accessions had lower seed yield. Because of the high demand for this seed color across all over the world, enhancing the seed yield warrants a great deal of attention of the researchers engaged in improving of the crop. There are implications from the variations would provide a basis for a genetically diverse breeding among high performing accessions in this study. They program and provide diversity. It can be concluded that Ethiopian fenugreek landraces contains accessions that vary widely in the studied traits.
The author wish to thank Mr. Mekonen Dagne for the invaluable assistance in handling the field trial and laboratory work. The financial assistance from Haramaya University, Vice-president for Research, for the research work is highly acknowledged.
APPENDIX
The commercial variety Challa was compared to ten highest ranking fenugreek accessions, as shown in Table A.
Table A: | Traits of the ten highest ranking accessions of fenugreek for biomass and seed yields, days to maturity, number of podding nodes, effective nodules and thousand seed weight as compared to Challa |
DF: Days to 50% flowering, PH: Plant height in cm, BMY: Biomass yield in g per plant, PPP: No. of pods per plant, SPPL: No. of seeds per plant, SPP: No. of seeds per pod, TSW: Thousand seeds weight in gram, SY: Seed yield in g per plant, HI: Harvest index in percentage, DM: Days to 90% maturity, GFP: grain filling period, NPPL: No. of nodes per plant, PNP: No. of podding nodes per plant, PBR: No. of primary branches per plant, SBR: No. of secondary branches per plant, NOP: No. of nodules per plant, ENO: No. of effective nodules per plant, ENOPPL: No. of effective nodules per plant, FW: Fresh, weight of nodules in g per plant and Sc: Seed color |