Agronomic performances, yield and nutritional values of lupin grain varieties at Gircha research center, Gamo Highlands

Abstract

Lupin is a multipurpose legume used for food and feed. However, its production is limited to the northern and northwest highlands of Ethiopia. It is important to evaluate productivity of different varieties in different locations of the country. Therefore, this experiment aimed to evaluate agronomic performances, yield and nutritional values of lupin grain varieties in Gamo Highlands, southern Ethiopia. The field experiment consisting of three treatments (varieties) with five replications arranged in randomized complete block design (RCBD). The experiment was carried out for two consecutive rainy seasons. Data on plant height, days to flowering, days to maturity, number of tillers and pods (plant-1), pod length, seeds per pod, grain yield and thousand grains mass (g) was collected. Plant height (cm) at maturity for sanabor variety (86) was significantly higher (p < 0.05) than plant height of the local (79.7) and vitabor (78.9) varieties. Days to flowering was significantly different (p < 0.001) between varieties. Number of tillers per plant was higher (p < 0.05) for sanabor (7.79) as compared to Vitabor (6.11) and local variety (4.74). Straw dry matter yield (t/h) of the local (4.06) and sanabor (3.85) varieties were higher than Vitabor (3.41). Grain yield (t/h) of 4.74, 4.08 and 3.75 were recorded for local, sanabor and Vitabor varieties. The cost benefit analysis indicated that growing sanabor variety has the highest net return and profitable. From the biomass perspective/feed value, growing the local variety is recommended.

Keywords:

• Agronomic performance
• lupin
• profitability
• yield
• variety

REVIEWING EDITOR:

• Manuel Tejada, Universidad de Sevilla, Sevilla, Spain

SUBJECTS:

• Agriculture & Environmental Sciences
• Plant & Animal Ecology
• Nutrition

Introduction

In the highlands of Ethiopia, livestock production is inseparably linked to crop production because of the mixed crop livestock farming system (Alemu, 2016). One of the major constraints limiting the increased livestock production on smallholder resource-poor farms in the tropics is the inadequacy of animal feed resources, especially during the dry season. Natural pasture and crop residues are the main feed resources in the region. The quality and productivity of natural pasture especially during the dry season is low. The nutritive value of crop residues is inherently low (Yenesew et al., 2015). Agro-industrial by-products have a high nutritive value. However, they are expensive and are less accessible to smallholder farmers in rural areas.

Therefore, identifying alternative home-grown protein supplements is crucial for improving livestock production and productivity. Growing and using legume crops with a high nutritive value are an option to solve this problem. Among grain legumes, lupin species seem to be a realistic sustainable alternative source of protein in both monogastric and ruminant feed that can replace soybean without loss in the quantity and quality of livestock products (Sedláková et al., 2016; White et al., 2007).

White lupin (Lupinus albus) is one of the four cultivated lupin species, and is a widely known annual legume crop for human consumption and animal feed in some countries. Although a shortage of protein sources limits livestock production in Ethiopia, the contribution of lupin as a livestock feed has remained negligible. In Ethiopia, the local lupin variety, also known as Gibto is the predominant species produced by small-scale farmers. Farmers produce crops for multipurpose benefits, such as soil fertility maintenance, nutritional value as snacks, local soup and local alcohol preparation, and for traditional therapy purposes (Getachew, 2009; Shimels & Tizazu, 2010). Consequently, farmers have shown increasing interest in cultivating white lupin (Yeheyis et al., 2010). The local bitter tasting lupin is widely grown in the northwestern part of Ethiopia for soil fertility maintenance, forage, human consumption and as a supplement to low-quality roughages.

All of these food values, together with their role in soil fertility maintenance, make white lupin a dependable potential crop for the future. Lupin is produced as the sole crop or intercropped with other crops. When white lupin is produced as a sole crop, it is produced with minimum agronomic practices, such as zero tillage, with no cultivation, and weeding practices, which are the main causes of low productivity and inconsistent production status of the crop. Lupins have been shown to offer a safe, cost-effective and high-protein feed supply for livestock as an alternative to soybean (Glycine max L.). Recently, sweet varieties of lupine have been introduced into the country. However, the potential benefits of lupin as food and feed crops remain limited (Yeheyis et al., 2010; Yilkal, 2011). Likewise, its production is limited to the northern and northwest highlands of Ethiopia (Habtemariam et al., 2019). Evaluation of agronomic performance and nutritional quality in different agro-ecologies and locations of the country is important for devising exhaustive utilization protocols for lupin species. In Chencha, in particular, and Gamo Highlands, in general, a shortage of feed is critical. At the same time, lupin has never been cultivated in this area. Therefore, this study was initiated to evaluate agronomic performances, yield and yield related traits; and nutrient contents of three lupin grain (Local bitter, sanabor and vitabor) varieties at Gircha research center, Gamo Highlands.

Materials and methods

Study area

The study was carried out in the Chencha district of Gamo zone at Gircha Highland Fruits and Vegetables Research Center, which is owned by Arba Minch University. Chencha District is situated between 1300 m and 3250 m above sea level. Astronomically Chencha district is located between 37° 29′ 57″ East to 37° 39′ 36″ West and between 60° 8′ 55″ North and 60° 25′30″ South. The District has two agro-ecological zones, namely, highland (>2500 masl) and midland (2000–2500 masl), which account for approximately 82 and 18% of the total area, respectively. Owing to its rugged topography, the highland area is highly vulnerable to soil erosion. The rainfall regime in the district is bimodal. The first round of rainfall occurred between March and April. The second round of rainfall occurred from June to August. Rainfall distribution in Chencha varies from year to year and across seasons. The annual rainfall distribution in the district varies between 900 and 1200 mm. The average minimum and maximum temperatures of the district are 12 and 20.1 degree centigrade, respectively (FAO, 1990). The altitude of Gircha is 3007 m above sea level (WVE, 2012). The farming system in the district is a mixed farming system in which crop and livestock subsystems are practiced.

Experimental design and treatments

Three varieties (Sanabor, Vitabor and local) of lupin grains were collected from the Amhara Regional Agricultural Research Institute (ARARI) Bahir Dar. Sanabor and vitabor varieties are sweet, while the local variety is bitter. The seeds were then manually cleaned. A randomized complete block design (RCBD) with five blocks and three plots per block was employed. Each of the three varieties were randomly distributed in the plots of each block. A plot size of 4 m × 5 m was used. The spacing was 7 cm between plants and 30 cm between rows (Yenesew et al., 2015).

Planting was conducted in the main rainy season (June-July) during the two cropping years (2021 and 2022). The land was cleaned and plowed 3 times before planting to provide a fine seedbed. Planted species management activities such as hoeing, weeding, diseases and pest inspection were conducted. Hand-weeding was conducted twice: once at the seedling stage and once just before the flowering stage.

Data collection

Plant height (cm) was measured on five plants per plot, selected randomly from the soil surface to the tip of the plant. Grain yield per area unit (kg ha-¹), plant height (cm) and grain yield components, including number of pods (plant-¹), number of grains (plant-¹) and thousand grains mass (g) were measured. Number of pods/plant, pod length (cm) and number of seeds/pod were measured on 5 randomly tagged plants/plot at maturity. The number of pods per plant, pod length and number of seeds/pod were measured in five randomly tagged plants/plots at maturity. The analysis of plant height, number of pods, number of grains and thousand-grain mass was based on the samples taken immediately before harvest. Number of branches per plant was determined for five randomly tagged plants/plot at 50% flowering. To determine the 1000-seed weight, 1000 seeds were randomly selected from the harvested seeds for each plot and weighed.

Chemical analysis

Chemical analysis of the different varieties was carried out at Hawassa University, Animal Nutrition laboratory. After harvest, the dry seeds of each lupin variety were ground separately to obtain grain flour. The samples were then ground to pass through a 1-mm sieve, and the ground samples were used for laboratory analysis. The samples were analyzed on a% DM basis for crude protein (CP), DM and ash determination following the procedure described by AOAC (2005). The acid detergent fiber (ADF) and acid detergent lignin (ADL) components of each ingredient and feces were determined according to the procedures of Van Soest and Robertson (1985), whereas the NDF content was analyzed following the procedures of Vansoest et al. (1991). Ash content was determined by heating the samples in a furnace at 550 °C overnight, and organic matter (OM) content was calculated as DM minus ash (AOAC, 2005). Nitrogen (N) content was determined following the micro-Kjeldahl digestion, distillation and titration procedures (AOAC, 2005), and the CP content was estimated by multiplying the N content by 6.25. Moisture, crude fat, crude protein and ash contents were assessed according to the methodologies detailed in AOAC (2005). The contents of major minerals such as calcium (Ca), phosphorus (P), iron (Fe) and zinc (Zn) were analyzed using atomic absorption and mass spectrometry (2005).

Cost-benefit analysis

The purchasing Prices of Lupin seeds were known, and the selling price was estimated in Birr/kg. The selling price of lupin grain per hectare was also calculated. The labor costs (land preparation, sowing, weeding and harvesting) were common for all treatments/varieties. Partial budgeting is used to assess the profitability of any new technology to be imposed on agricultural businesses (Upton, 1979). The net return was estimated for each variety yield (kg ha-¹) observation produced on average farm gate prices of local, sanabor and vitabor varieties.

To measure the increase in net return associated with each additional unit of cost (marginal cost), the marginal rate of return (MRR) was calculated as: ΔNI/ΔIC; Where, MRR is the marginal rate of returns, ΔNI – change in net income compared with control/local variety, and ΔIC – change in input cost compared with control. The following points were considered during cost benefit analysis using a partial budget.

• Costs for all agronomic practices were uniform for all treatments within sites.

• Costs, returns and benefit were calculated per hectare basis.

Statistical analysis

The raw data were subjected to ANOVA and analyzed using SAS statistical software (SAS, 2009) version 9.2. When the analysis of variance revealed the existence of significant differences among the treatments, means were separated using Tukey’s test. The following statistical model was used for the data analysis: $$\mathit{\text{Yij}}=\mu +\mathit{\text{vi}}+\mathit{\text{bj}}+\mathit{\text{eij}},$$ where Yij is the response variable (the observation in jth block and ith treatment), µ is the overall mean, vi is the variety effect, bj is the block effect and eij is the random error.

Result and discussion

Agronomic performances

Agronomic performance (plant height, days to flowering and maturity, number of tillers and straw dry matter yield) is presented in Table 1. Plant height (cm) at maturity was recorded to be 79.7, 86 and 79.9, respectively, for local, Sanabor and Vitabor varieties, respectively. No significant differences (p > 0.05) were observed in plant height among the lupin grain varieties. Lower than the present results, plant heights (cm) of 67.7 and 53.8 were reported for sanabor and Vitabor varieties grown in Dabat District of North Gondar Zone (Friehiwot et al., 2019). Plant heights (cm) of 80–124 also noted for inoculated white lupin (Sulas et al., 2012). Mean plant height of 82 cm for different lupine varieties was reported by Rudloff (2011). This discrepancy may be due to environmental variations in the study area. Edwards et al. (2011) also reported that the plant height of narrow-leafed lupin varieties varied from 20 to 100 cm.

Table 1. Plant height, days to flowering/maturity, number of branches per plant and forage dry matter yield of lupin varieties.

Variables		Days to flowering	Days to maturity	Plant height (cm)	Number of branches	Straw DMY(t/h)
Variety	Local	67.70^a	140^a	79.70	4.74^b	4.06^a
	Sanabor	52.80^b	103.90^b	86.00	7.79^a	3.85^a
	Vitabor	55.80^b	108.80^b	78.90	6.11^b	3.41^b
	CV	10.65	6.41	7.25	20.92	8.73
	p-Value	<0.001	<0.001	0.036	0.0001	0.0007

Values in columns with different letters (a, b, c) vary significantly; cm: centimeter; DMY: dry matter yield, t/h: tone per hectare.

Days to flowering were significantly different (p < 0.001) between the local (67.7 days) and sweet varieties (52.8 and 55.8 days for the sanabor and Vitabor varieties, respectively). Similar results on days to flowering of sanabor (58.33 days) and Vitabor (60.66 days) varieties have been reported (Fikadu, 2021). Days to flowering in Sanabor has been reported to be 87 days (Friehiwot et al., 2019). The variation in days to flowering might be associated with the soil types and varietal differences. The days to plant maturity in the current study were significantly different (p < 0.020) for the local and sweet varieties. The highest number of days to maturity was recorded (140 days) for the local lupin grain varieties. Fikadu (2021) also reported days to maturity for sanabor and Vitabor at 117.33 and 119.66 days, respectively. In a similar study, longer days of maturity (167–233 days) were reported in the Mecha and Sekela districts of the West Gojjam zone (Zerihun, 2012). This may be due to agro-ecological variations in the study locations/sites. Mergia (2021) noted number of branches, pods/plant and straw dry matter yield (t/h) of sanabor variety as 11–20, 23–35 and 0.52–1.6, respectively, for different accessions of lupin in the highlands of Ethiopia. The local variety (4.06t/h) and sanabor (3.85 t/h) had the highest forage straw yield. Yenesew et al. (2015) reported mean straw dry matter yield of 4.2 ± 2.91 (t/h) for sweet lupine in south achefer district. Very low straw dry matter yield (t/h) of 1.45 and 1.53 were reported for Sanabor and Vitabor in Gondar area (Alemu et al., 2019). Forage yield of 0.6–1.7 tons per hectare were recorded for vitabor and sanabor varieties at midland and highland altitudes in the gojjam area (Fikadu, 2021). These variations in number of branches and straw yield, might be due to environment and genotype differences.

Grain yield and related traits

The grain yields and yield-related traits of the three lupin grain varieties are presented in Table 2. The number of pods per plant was not significantly (p > 0.05) affected by the variety, with an overall range of 19.35 to 21.1 pods/plant. The number of pods per plant (55.59) for sanabor and (52.17) for Vitabor were noted (Fikadu, 2021). This may be associated with differences in soil fertility levels and other management practices. The number of pods per plant was 8.1 to 16.9 pods/plant was reported in the highlands of Ethiopia (Friehiwot et al., 2019). A very small (5.4) mean pod number per plant has been reported (Pospišil, 2015). Pod length was significantly different (p < 0.01) and was higher for the local variety. A mean pod length of 4.3 cm was reported by Fikadu (2021) for sanabor and Vitabor varieties in the lemo and hadya zones. Similar findings on the number of seeds per pod (4.09) for the Haag blue variety have been reported in Gondar Zuria (Alemu et al., 2019).

Table 2. Grain yield and yield related traits of lupin grain varieties.

Variables		Pod number	Pod length	Seeds per pod	1000 seeds weight (g)	Grain yield (t/h)
Variety	Local	19.35	8.20^a	6.10	3895^a	4.74^a
	Sanabor	20.7	5.28^b	6.00	2140^b	4.08^b
	Vitabor	21.10	5.46^b	5.98	1693^c	3.75^b
	p-Value	0.48	<0.0001	0.97	<0.0001	0.0009
	CV	16.43	15.15	18.10	11.14	12.18

Values in columns with different letters (a b c) vary significantly; gm: gram; t/h: tone per hectare.

The same author noted 4.35–4.95 seeds per pod for Vitabor and Sanabor sweet lupin varieties. The number of pods per plant has been reported to be 3.7–6.8 for different varieties (Vojislav et al., 2008).

The number of seeds per pod in the present study was relatively higher than the range value of values 4.33 to 4.67 reported by Teklay et al. (2015) for Bora and Sanabor genotypes tested in the Tigray region. Different genotypes performed differently in the number of seeds per pod at different locations, which might be attributed to variations in agro-ecological conditions, such as soil-associated factors, moisture, temperature and management practices. Pod length, number of seeds per pod and grain yield were significantly influenced by crop years.

The 1000 seed weights of lupin varieties varied significantly (p < 0.001), and the highest (3895 gm) was recorded for the local lupin grain. Lower values (135–290 g) have been reported for different accessions (Pospišil, 2015). The grain yield performance of all lupin varieties was satisfactory. The grain yield in the current study differed significantly (p < 0.001) between varieties. The highest (4.06 t/h) was recorded for the local variety. Comparable to the present findings, Temesgen (2019) noted a mean seed yield per hectare of 3.982.29 ton for different lupin grain accessions in the Amhara region. Grain yield of sweet lupin (Sanabor) was reported to be 2.2 t ha-1 to 4.8 t ha-1 depending on the area (Yeheyis et al., 2010). Similarly, Fikadu (2021) recorded grain yield of 2.52 and 2.61 t/h for Vitabor and sanabor varieties in Lemmo district Hadya zone. Lower than that in the current study, Vojislav et al. (2008) revealed a grain yield of 1.425–3.005 (t/h) for different lupin grain varieties.

Chemical composition

The chemical composition of the lupin grain varieties tested is listed in Table 3. There were no significant differences (p > 0.05) in DM, ash, EE and ADL contents among the different varieties. Higher Crude protein (CP) content recorded for local variety (29.08%) than Vitabor variety (24.19%). Higher NDF values were recorded for sanabor and Vitabor than for the local variety. Similar dry matter content (92%) were reported for the same crop (Yilkal, 2011). Higher dry matter (94%) has also reported in local varieties (Mazumder et al., 2021). Mergia (2022) reported similar CP content of 22.5% for sanabor variety in the highlands of Ethiopia. Fikadu (2021) reported slightly different (22.4% and 21.85%) of crude protein for Vitabor and Sanabor varieties, respectively. The same author noted higher NDF (47%) content for both Vitabor and Sanabor varieties. Similarly, higher protein (39%) and fat (9.1%) was reported for local variety (Biadge et al., 2022).

Table 3. Chemical composition of different lupin grain varieties.

Variables		DM (%)	%DM
			ash	CP	EE	NDF	ADF	ADL
Varieties	Local	91.60	3.57	29.08^a	3.57	31.83^b	19.25^b	3.76
	Sanabor	92.00	3.68	24.19^b	3.16	36.42^a	23.74^a	3.62
	Vitabor	91.80	3.82	19.37^c	2.89	37.79^a	25.44^a	4.00
	p-Value	0.3039	0.0875	<0.0001	0.209	<0.0001	<0.0001	0.4291
	cv	0.58	6.67	15.79	26.01	5.39	11.72	17.54

Values in columns with different letters (a b c) vary significantly; DM: dry matter; CP: crude Protein; EE: ether extract; NDF: neutral detergent fiber; ADF: acid detergent fiber; ADL: acid detergent lignin; %: percentage.

A total ash content of 3.2% for local lupin grains was reported by Shimels and Tizazu (2010). Differences may arise because of the soil/location, agro-ecology and season of grain cultivation. Teshome et al. (2012), who collected two bitter lupin samples from Amahara Region (Gojjam), obtained protein contents 38.92% (Dangela) and 37.56% (Chagini), which is comparable to the study by Kefale and Abrha (2018), who noted protein content of 31.65% for sweet lupin grain.

Mineral profiles of lupin grain varieties

Some of the mineral contents (mg/100 g) in lupin grain varieties are presented in Table 4. There was no variation (p > 0.05) in the zinc content among the three grain varieties. Higher (105.62 mg/100 gm) calcium content for the local variety followed, respectively, by 95.55 mg/100 g and 88.68 mg/100 gm for sanabor and Vitabor varieties recorded. Shimels and Tizazu (2010) observed significant variations among white lupin landraces for phosphorus and calcium contents in the range of 979.8 and 2487.7 μg/g and 671.3 and 2490.2 μg/g, respectively, using the genotype of lupin (L. albus) seeds that were collected from the local markets of Dembecha and Debretabor in the Amhara region (northern Ethiopia). However, from both locations (Dembecha and Debretabor), they observed 2489, 125.1 and 825.6 μg/g, phosphorus, iron and calcium contents, respectively. Getachew (2009) also reported 60.0 and 67.2 μg/g contents of Iron for Dangla and Tilili white lupin genotypes, respectively. Zelalem and Chandravanshi (2014) reported significant differences among white lupin genotypes for calcium and iron in the ranges of 502–967 and 78–93 μg/g, respectively.

Table 4. Mineral profiles of different lupin grain varieties.

Variables		Mg/100 g
		Ca	P	Fe	Zn
Varieties	Local	105.62^a	273.59^b	9.17^b	4.253
	Sanabor	95.55^b	306.68^a	11.50^a	4.413
	Vitabor	88.68^c	303.94^a	11.46^a	4.579
	p-Value	<0.0001	<0.0001	<0.0001	0.5849
	CV	3.90	3.11	9.13	15.76

Values in columns with different letters (a b c) vary significantly; Ca: calcium; P: phosphorus; Fe: iron; Zn: zinc; Mg: milligram; g: gram.

Zemenay (2019) also noted 99.29, 3.83 and 17.36 (mg/100 gm) calcium, iron and zinc contents in local lupin grain variety. Element uptake in plants is a function of element concentrations in soils, soil pH, cation exchange capacity, organic matter content, types and varieties of plants and the age of the plant (Tsegaye & Struik, 2001). According to a study by Wickramasinghe (2017), the mineral content of sweet lupine is K (9.5–11.6), Mg (1.4–1.8), Ca (1.0–1.9), Mn (1316–1370), Fe (39–43), Zn (38–49). The biological utilization of dietary minerals is dependent on several factors, including antinutritional components such as phytate, which may adversely affect mineral absorption.

Cost-benefit analysis

Partial budgeting is a planning and decision-making framework used to compare the costs and benefits of alternatives for a farm business. Although the local variety was able to produce a higher grain yield of 42,660 kg-h, its market price is not comparable to that of the sweet varieties; hence, the net return is far less than that of the sanabor and vitabor varieties (Table 5). The highest net and marginal rates of return were recorded for the sanabor variety. This may be because local people prefer to fetch high prices. The highest net benefit of Birr 1,617,650 ha-1 was recorded for the sanabor variety, whereas the lowest net benefit of Birr 608,400 ha-1 was obtained from the local variety. The marginal analysis results revealed that Sanabor had a marginal rate of return (MRR) of 310.54%, which is well above the minimum acceptable rate of return (100%). This shows that farmers could receive a net return of Birr 2.96 for each Birr invested in the Sonabor variety rather than the local variety. Marginal rate of return (MRR) of 491.76% was obtained from Vitabor, which is higher than Sanabor. Therefore, the Vitabor variety of grain was economically feasible and recommended based on partial budget analysis.

Table 5. Cost benefit analysis of growing lupine grain varieties.

Variables	Varieties
	Local	Sanabor	Vitabor
Seed yield (kg/h)	47,400	40,800	37,500
Adjusted yield (kg/h)	42,660	36,720	33,750
Cost of production (ETB/h)	30,000	30,000	30,000
Selling price of grains (ETB/kg)	15	45	40
seed cost (EB/h)	1500	4500	4000
Gross field benefit/gross return	639,900	1,652,400	1,350,000
Total Variable cost (EB/h)	31,500	34,750	36,000
Net return	608,400	1,617,650	1,314,000
MRR (%)	–	310.5385	156.8

Kg/h: kilogram per hectare; ETH/h: Ethiopian Birr per hectare; ETB/kg: Ethiopian birr per kilogram; %: percent.

Conclusion

All the tested varieties perform well in terms of plant height, number of tillers and grain yield parameters. Difference in growth and yield performances were also recorded among the different varieties. The local variety performs better than the introduced sweet varieties in grain yield. Demonstration of these (sweet varieties) to farmers and awareness creation about their utilization is suggested.

Authors’ contributions

Yilkal Tadele designed the method, executed data collection and analysis and wrote the manuscript. Seifu Birhanu contributed to data checking, writing and editing of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

The authors are grateful to Arba Minch University for sponsoring this research work.

Notes on contributors

Yilkal Tadele

Yilkal Tadele (PhD) is working in Arba Minch University as an assistant Professor. He is an animal nutritionist. He has published more than twelve research and review articles.

Seifu Berhanu

Seifu Berhanu (MSc) is a staff of Arba Minch university. He has rich experiences in teaching and research. His profession is Animal Science with emphasis to dairy Production and Processing.