Effect of Earthing-Up Frequency on Growth and Yield of Anchote ( Coccinia abyssinica ) Varieties at Gimbi District, Western Ethiopia

Anchote ( Coccinia abyssinica (Lam.) Cogn) is a tuberous root crop native to Ethiopia. It is a good source of protein, carbohydrates, calcium, and iron. However, little attention has been given to the improvement of genetic and agronomic practices such as selection of variety, staking, weeding, fertilizer application, and earthing-up frequency. Tus, the attainable yield is below the potential. Te experiment was arranged in a 3 × 5 factorial arranged in a randomized complete block design (RCBD) with three replications with the objective of determining the efect of earthing-up frequency on the growth and yield of anchote varieties. Te interaction efect of earthing-up frequencies and varieties signifcantly afected anchote leaf number plant − 1 , shoot dry weight plant − 1 , unmarketable tuber weight ha − 1 , vine diameter, shoot fresh weight plant − 1 , tuber fresh weight plant − 1 , marketable tuber weight ha − 1 , and total tuber yield ha − 1 . Total tuber yield ha − 1 was perfectly correlated with tuber fresh weight plant − 1 ( r =1), and all parameters were signifcantly correlated with tuber dry matter plant − 1 , and tuber dry matter plant − 1 was positively and sig-nifcantly correlated with total tuber yield ha − 1 ( r =0.46). Consequently, the highest total tuber yield was observed from earthing-up four times (26.94t ha − 1 ) and three times (26.88 t ha − 1 ) with Desta 01, while the lowest was observed from the control with Acc405 (15.11). Te highest economical tuber yield was obtained from three times earthing-up frequency (26.878t ha − 1 , 25.50t ha − 1 , and 23.92t ha − 1 for Desta 01, Acc405, and Acc173), and the lowest was observed from the control (22.83 t ha − 1 , 15.11t ha − 1 , and 21.11 t ha − 1 for Desta 01, Acc405, and Acc173), respectively. Terefore, for the study area, it is better to apply three times earthing-up frequencies (35 days, 49days, and 63days from planting date for once, twice, and three times earthing-up, respectively) with Desta 01 variety followed by Acc405. Since the experiment was conducted using irrigation, it is suggested to be repeated under rainfed conditions to draw a defnite conclusion.


Introduction
Anchote (Coccinia abyssinica (Lam.)Cogn.) is a short life cycle plant known by trailing vine belonging to the cucurbitaceous family.In Ethiopia, the cultivation of anchote is limited to the western and south-western parts of Ethiopia such as Wollega, Kafa, Sidama Jimma, and Illubabor [1,2].Anchote is produced for its tuberous root though its young immature leaves are also used as food in some areas [3].It is used as a cultural, social, and economic crop for the community of anchote-producing area [4].It is important as food and forage for people and livestock, respectively [4].Anchote dish is known for its cultural food in the western region of the Oromo people, such as the celebration of the Ethiopian Meskel holiday (the fnding of True Cross) and other holidays.Food prepared from anchote is the frst to be served in the town and rural communities of the western regions of Ethiopia [5].Te food from anchote is also mixed with diferent green pepper paste, which is named "kochkocha" and ghee, and eaten with diferent bread, made of tef, maize, and wheat.Anchote dish is considered a unique and cultural food, which specifes western regions of Ethiopia.However, its expansion to other diferent parts of the county is very limited [2].Tis could be because of low agricultural productivity, overdependence on some cereal crops, limited research coverage, and little attention given to this crop at a national level; which brings the absence of information on suitable planting time, lack of planting materials, shortage of released varieties, lack of awareness on production and utilization could be considered as a bottleneck for its good distribution [2].
Little attention has been given to anchote research and development [2].Consequently, there is only one variety so far developed and released by Debre Zeit Agricultural Research Center [6].Due to this problem, it is widely known that poor agronomic practices and traditional selection practices are being followed by farmers to have anchote types of desired quantity and quality, such as larger tuber size [2].In Ethiopia, no study has been conducted on anchote earthing-up frequency.Terefore, in the study area, farmers usually apply to earth up to their anchote crop only once.Besides, they use landraces, which are very low in production and productivity.
Anchote has the potential to produce a tuber yield of 20-30 t ha −1 under farmer's conditions [7] and from 73 t ha −1 to 76.45 t ha −1 under research stations [2,8].However, the average yield of anchote in the Gimbi district is 14.35 t ha −1 , while 10-15 t ha −1 for western Oromia zones [9].Among other factors, this yield gap of anchote is partially attributed to the low frequency of earthing-up [10] because adequate earthing-up results in plants having a larger area of root volume to gain enough water and nutrients for tuber development, which needs for photosynthesis [10,11].Besides, earthing-up minimizes the soil temperature, which is used to facilitate tuber growth and formation [10,12].Earthing-up also protects the tuber from insect damage by barring the tuber in the soil [13].Hence, it needs to optimize and ensure the earthing-up frequency of anchote through research, since in anchote crop production, earthing-up is critical in that it creates a favorable condition for tuber growth and development.
Anchote has a high return for the farmers.However, most farmers are failing to achieve high yields partly because they do not adequately earth-up their anchote crop [10].Anchote has a relatively short growing period, which means that it is one of the acceptable alternative crops to withstand the population pressure in developing countries like Ethiopia to minimize hunger because anchote is known to withstand draught and can substitute other food crops.Besides, within a single year, it can be produced more than once.When farmers do not adequately earth-up their anchote crop, the reward or advantage of anchote production cycle is shortly meaningless, as it will not bring away the good consequences in line with [10] who confrmed that the earthing-up frequency was carried out in order to increase yield in case of potato [14].Besides, the positive efect of earthing-up of any level of sweet potato on marketable tuber was signifcantly higher than no earthing-up.Western Ethiopia is one of the high rainfall receiving areas and known for diferent root and tuber crop cultivation, specifcally anchote, which is highly coupled with the life of the community in the area [2,5].Tus, anchote is a potential crop produced on nearly 3,000 ha, 743 ha, and 29 ha of land in the West Wollega Zone, Gimbi district, and weraseyo peasant association [7], and Gimbi district has a high potential for anchote production [2, 3 15].Tough anchote is produced on large coverage of land and too interlinked with the life of people in Gimbi district, their existing practice of its production is very poor, and in other anchote-producing areas, the crop has been grown under poor agronomic practices, particularly earthing-up frequency [2,3,15].Consequently, their reward is too low as compared to the potential yield as stated for all regions of the anchoteproducing area [2,3,10,15].Terefore, the overall objective of this study was to assess the growth and root yield response of anchote varieties to the earthing-up frequency at Gimbi district, western Ethiopia.

Description of the Study Area.
Te study was carried out in Weraseyo peasant association, in Gimbi district, western Ethiopia and located 5 km from Gimbi district which is located 441 km from Addis Ababa.Te site is found between Gimbi town in South West, Lalo Choli peasant association in the North, Choli Mikael peasant association in the West, and Lelisa Sarity in the east direction.Geographically, it is located between 9 °10′ N latitude and 35 °44′ E longitude while its altitude range is 1824 to 1872 m a.s.l (Figure 1).Besides, from personal observation, the soil of the study site has sandy (40%), clay (30%), and silt (30%); the soil is clay loam, which is good for most crops.

Experimental Material.
Tree varieties of anchote were obtained from the Debre Zeit Agricultural Research Center and used in this study.Two of them (Acc405 and Acc173) were in the pipeline to be released.Te released variety, Desta 01, which yields an average yield of 32 t ha −1 , matures at 120 days, and creamy fresh root color has been used for the study.Te descriptions of the three varieties are shown in Table 1.

Treatments and Experimental Design.
Five levels of earthing-up frequency are no earthing-up, earthing-up once, earthing-up twice, earthing-up three times, and earthing-up four times and tree varieties of anchote (Desta 01, Acc405, and Acc173 were used as treatments combination).Te experiment was arranged in a 3 × 5 factorial arrangement in a randomized complete block design (RCBD) with three replications.Te plot sizes were fxed at two meters long and two meters wide, and each plot had fve rows with 10 plants in each and with row spacing of 40 cm.Tere was a 20 cm distance between the plants, and the plots were 0.6 m apart from each other and 1 m between replications.Te total numbers of plots were 45.Tree seeds per hill were sown and fnally thinned into one seedling per hill after complete emergence.Seeds were sown on well-prepared fve rows per 2 International Journal of Agronomy bed at a 5 cm depth in the soil directly on the bed [8].Data were recorded from 15 randomly taken plants (from the three middle rows of the fve rows per plot) in line with the experiment conducted on sweet potatoes [16] and cucurbit species [17].

Experimental Procedure
2.4.1.Land Preparation and Sowing.Te land was plowed by oxen.Fine seedbeds were prepared and used for the ease of seed planting [15].Ten, planting blocks and plots were opened using a hoe, which was used for the row marker.Te rows were straightened using a plastic thin rope line and sharp wood.Tis operation was followed by the pegging of three blocks with ffteen plots.Local wooden pegs have marked all plots [15].Te sowing of anchote seed was carried out on 07 December 2020.
Tough there is no seeding rate recommendation, there were 125,000 seedlings ha −1 [8].Tis seed was covered by a thin thickness of soil to be sown at a shallow depth and spaced at 20 cm within the row.Te rows were spaced 40 cm from each other.Tree seeds were placed at each planting station.Te sown seeds were then covered completely with soil with care not to heap too much soil above but to minimize seed emergency barriers.

Fertilizer Application.
Te recommended rate of N and P is 46 kg ha −1 and 20 kg ha −1 , respectively, but P in NPS-blended fertilizer is in the form of P 2 O 5 (19% N: 38% P 2 O 5 : 7% S graded).Terefore, 45.8 kg ha −1 P in the form of P 2 O 5 was used [7].Consequently, based on this recommendation, 120.53 kg ha −1 and 50.21 kg ha −1 of NPS and Urea were applied, respectively.Te fertilizer was applied in the band; this means that the application was 2.17 kg and 0.91 kg per total 45 plots for NPS and UREA, respectively.Ten, 0.048 kg and 0.02 kg of NPS and urea were applied for each plot, but urea was applied by split application, i.e., 0.61 kg (2/3 of the total recommendation) was applied at planting.

Earthing Up.
Te earthing up was carried out starting 15 days after the complete emergence of plants [18] even though anchote can be germinated 9 days after planting [2].However, in line with Mengesha et al. [8], the complete emergence occurred after 20 days while the rest of the three levels were carried out at every two weeks intervals from each other: 49 days, 63 days, and 77 days from the complete emergence date.Tis was carried out according to the experimental protocol of up to fve treatments, which required that some plots were earthedup once, some twice, some three times, and some four times while in some plots, earthing up was not carried out [10].Te diferent levels of earthing-up frequency could be implemented to evaluate appropriate earthing-up levels for the growth and root yield of anchote varieties.Te practice of earthing up was carried out to improve growth and yield parameters as earthing up lowered the soil temperature and protected the tuber from sunlight.However, in line with Sakadzo et al. [19], the earthing-up operation was ended three weeks before fowering to minimize economic loss.Terefore, a ridge of a uniform height was prepared at each earthing up to keep other factors constant.International Journal of Agronomy 2.5.Agronomic Practices.Te frst weeding was carried out after three weeks from the date of the emergency [10] because plants compete for nutrients, light, and water at the initial stage is comparatively higher that of other growth stages [20]; however, the rest weeding operations were carried out simultaneously at every earthing-up operation to clean up the feld.Appropriate feld sanitation and other agronomic practices such as watering schedules, staking, and weeding were wisely managed to minimize the occurrence of diseases and pests.However, no insecticide, fungicide, or nematocide was applied, since there are no serious diseases or pest problems.
2.6.Data Collected.Diferent treatments were harvested at diferent times (110 days to 139 days from the planting date according to varieties and experimental protocol) when more than 90% of the plants showed physiological maturity.Harvested yield from each plot was gathered separately to allow parameters to be measured.Te tubers were harvested manually by digging with hoes, and care was taken to separate the tubers produced by each crop.All samples on a plot were harvested, packed, and labeled separately for ease of identifcation.Terefore, data were collected on phenological traits, growth traits, and yield and yield components of the crop.
2.6.1.Phenological Traits.Days to 50% fowering was recorded as the number of days from planting when 50% of plants in each plot produced fowers (15,16,17,21].Days to physiological maturity recorded from plants in the plots, as the number of days from planting when 90% of leaves turned yellow [21]. 2.6.2.Growth Traits.Plant height was measured by tape meter at maturity, but before harvesting from the 15 sampled plants and taken from the base of the plant to the top of the shoot by using a graduating tape meter, and the mean was used for data analysis.Vine internodes length (cm) was measured by a graduated ruler at maturity, but before harvesting of the plant by taking the representative part or the middle portion of vines from 15 sampled plants, and the mean was taken for data analysis.Vine diameter (mm) was measured at maturity, but before harvesting, and taken at 12 cm above the ground or middle part of the vine from 15 sampled plants.It was measured by a caliper meter and calculated for each plant.
Number of leaves per plant was counted from each sampled plant and divided by the total number of 15 sampled plants.Leaf length (cm) was recorded after fowering, but before the full maturity stage by measuring the length of the leaves in cm; which was taken from the middle parts of the plant by selecting 15 leaves at random from every 15 plants from the plot and then, mean was taken.After fowering but before reaching complete maturity, the breadth of the leaves (measured leaf width (cm)) was measured from the central sections of the plant by randomly picking 15 leaves from each of the 15 plants in the plot.Te mean of the measurements was then obtained for analysis.Tis was done after fowering but before the full maturity stage.Shoot fresh weight per plant (kg): to calculate the shoot fresh weight for a specifc plant, the weight of all the leaves, branches, and stems from 15 tested plants in each plot were weighed, and the result was divided by the total number of 15 sampled plants.Shoot dry weight per plant (kg) was obtained after drying the samples taken for determination of the shoot fresh weight in the open sun for seven days, and then, oven-dried was applied at 105 °C until a constant weight of 10% was attained for 24 hrs.

Yield and Yield
Components.Tuber fresh weight per plant (kg): all treatments were harvested and weighed separately by digital balance.Te average weight of fresh tubers per plant was determined by dividing the initial tubers weight of 15 sampled plants per plot soon after harvest by the plant population within a sample of a single plot or divided by the number of 15 plants.Tuber dry matter content per plant (%): anchote tubers, which were harvested for fresh tuber weight per plant, were chopped into pieces.Ten, the tuber fresh weights were placed in paper bags and dried at 105 °C for 24 hours to a constant weight.Ten, the dry matter content was calculated as the weight of 15 sampled tubers after drying in kg divided by the initial weight of 15 sampled tubers in kg times 100.
Marketable tuber weight per hectare (t ha −1 ): anchote tubers, which were graded according to their free of blemishes, pest damage, and size of >100 g, were regarded as marketable as in the case of sweat potato [8].So, the weight of marketable tubers per hectare was determined by weighing the weight of tubers from the whole three middle rows from each plot in kg and converting it to the weight of total marketable tuber weight in each plot.Finally, the marketable tuber weight was recorded for a single plot and converted to marketable tuber weight per hectare.Unmarketable tuber weight per hectare (t ha −1 ) was measured in kg from the total storage root yield which was afected, damaged, and undersized (<100 g) as in the case of sweat potato [22] from whole three middle rows from each plot and calculated for each plot.Finally, the unmarketable tuber weight recorded for a single plot is converted to unmarketable tuber weight per hectare.Total tuber yield per hectare (t ha −1 ): the total yield per hectare was determined by the mean fresh weight of the tuber per plant multiplied by the plant population per hectare.

Cost-Beneft Analysis to Determine the Appropriate Earthing-Up
Frequency in Anchote Production.Cost-beneft analysis of the diferent levels of earthing-up frequency was carried out using a partial farm budget; total weeding and earthing-up costs were compared with net beneft [23,24].Terefore, it was estimated based on the formula developed by CIMMYT [25].Gross unadjusted tuber yield (kg ha −1 ) was the average yield of marketable tuber weight ha −1 .Adjusted tuber yield (kg ha −1 ): the average yield was adjusted downward by 10% to refect the diference between the experimental yield and the yield of farmers.Gross income/beneft (ETB ha −1 ) was computed by 4 International Journal of Agronomy multiplying the feld/farm gate price that farmers receive for the crop when they sell it as adjusted yield.Total cost (ETB ha −1 ) was the cost of labor for weeding and earthing up whereas other costs such as harvesting, land preparation, inputs, sawing, and transportation costs were assumed to remain the same or are insignifcant among treatments.Net beneft (ETB ha −1 ) was calculated by subtracting the total costs from gross income/benefts.Te marginal rate of return (%) was calculated by dividing the change in net beneft by the change in cost time 100.Model: where Y ij(k) = the mean value of the response variables of the i th earthing up at j th variety in k th blocks, μ = overall mean, E j = earthing-up efect, V k = variety efect, EV ik = interaction efect, R i = block efect, and έ ijk = random error term.

Phonological Traits
3.1.1.Days to 50% Flowering.Te analysis of variance indicated that the main efect of earthing-up frequency (p < 0.01) and varieties (p < 0.01) had a highly signifcant efect on days to 50% fowering.However, the interaction efect of earthing-up frequencies and varieties did not signifcantly afect day to 50% fowering.For earthing-up frequency, the maximum days to 50% fowering were obtained from four (91.81 days) and three (91.77days) times earthing up, and the lowest (80.77 days) was obtained from no earthing-up (control) frequency (Table 2).Tis could be because adequate earthing-up frequency can facilitate vegetative growth.On the contrary, the absence of earthing up creates stress on the plant because of lack of aeration and enough moisture thereby, resulted in high production of ethylene hormone, which facilitates the reproductive stage, particularly early fowering.Tis result is in line with the work of Getachew et al. [27], who stated that the lack of aeration and mechanical barrier of soil colloids can afect plant growth and bring early fowering to plants.For variety, the longest day to 50% fowering was recorded from Desta 01 (88.29 days) while the shortest was recorded from Acc173 (85.76 days) and Acc405 (86.13 days) (Table 2).Te study of Sadik et al. [21] which suggests that a variety of factors, including genetic and environment infuence how early potatoes fower, is supported by this result, which may be the result of the environment's ability to vary for diferent kinds.

Days to Physiological Maturity.
Both main efects of earthing-up frequency (p < 0.01) and varieties (p < 0.01) had signifcant efects on days to physiological maturity.However, their interaction efect had no signifcant (p < 0.05) efect on days to physiological maturity.Tis is in line with the work of Gutema (2016), who confrmed that the interaction efect of earthing up and tuber form of potato had no signifcant efect on the days to physiological maturity of potato.For earthingup frequency, the highest days to physiological maturity were recorded from four times (129.84days) and three times (129.30days) earthing up, while the least days to physiological maturity were obtained from control (114.65 days) (Table 2).Te reason for this may be because soil with no earthing up lacked enough moisture and was exposed to high temperatures, consequently probing the plant for the production of ethylene hormone which is the main cause of aging.Tis supports the fnding of Getachew et al. [27], who stated that stress could afect plant growth and bring early maturity to the plant whereas adding the soil to the plant could facilitate the mobilization of nutrients and regulate adequate temperature and moisture thereby prolonging vegetative growth over reproductive growth.Tis result supports the fnding of Getachew et al. [27], who reported that earthing up at 15 days after the complete emergence of the potato enhances vegetative growth that extends days to physiological maturity.For variety, the highest (123.36 days) days to physiological maturity were obtained from Desta 01, and the lowest (121.95 and 122.58 days) were recorded from Acc173 and Acc405, respectively (Table 2).Tis variance may result from genetic variability; variations in the plant's vegetative growth validate the fndings of Sadik et al. [21], who found that environmental and genetic factors regulate the number of days potatoes take to reach physiological maturity.International Journal of Agronomy

Plant Height.
Te interaction efect of earthing-up frequency and variety and the main efect of variety had no signifcant (p > 0.05 and 0.202, respectively) efect on plant height.However, the main efect of earthing-up frequency (p < 0.01) was highly signifcantly infuenced plant height of anchote (Table 3).Te longest plant height was obtained from earthing up four times (237.19cm) and three times (235.04cm), while the shortest was obtained from control (174.86 cm) (Table 3).Tis could be because adding soil to the plant is adding nutrients and moisture for the plant and is utilized by plants for their growth and development, specifcally plant height.Tis agrees with the fnding of Fitsum et al. [12], who indicated that the highest plant height was recorded from potatoes earthed up.Similarly, the authors of [28] reported that earthing up signifcantly afected the height of the onion plant, measured on diferent days after planting.

Vine Internode Length.
Te interaction efect of earthing-up frequency and variety and the main efect of variety did not signifcantly (p > 0.05 and 0.1473, respectively) afect the vine internode length of anchote.However, the earthing-up frequency had a highly signifcant efect (p < 0.01) on anchote vine internode length.Te highest vine internode length was obtained from four times (7.88 cm) and three times (7.85 cm) earthing up while the lowest was obtained from the control treatment (5.0822 cm) (Table 3).Tis result might be as the results of the diferent varieties of anchote vine internode length were infuenced by a change in soil condition because of added soil to the anchote.Te authors of [8] stated that the variability in internode length among accessions of anchote could be due to genetic diferences and/or environmental efects.

Leaf Length.
Te interaction efect of earthing-up frequency and variety did not signifcantly afect (p > 0.05) the leaf length of anchote.However, the two main efects (p < 0.01) had a highly signifcant efect on the leaf length of anchote.Te longest leaf length was observed from earthing up four times (9.72 cm) and earthing up three times (9.71 cm), while the shortest leaf length was observed from no earthing up (7.46 cm) (Table 4).Tis might be because the active growth stage of the plant was improved by the soil porosity, aeration, better root growth, and penetration for nutrient absorption thereby increasing leaf length for the requirement of metabolic activities.Tis result agrees with that of Getachew et al. [27], who stated that the largest leaf area was obtained from potato earthing up after a complete plant emergency coincided with the increased plant growth and development that ultimately increased the leaf area of potato.In the case of variety, the longest leaf length was obtained from Desta 01 (8.64 cm) and Acc405 (8.51), and the shortest was observed from Acc173 (8.32 cm) (Table 4).Tis result may be due to the genetically unique characteristics of diferent varieties.Te results are consistent with the fnding of Mengesha et al. [8], who reported that the presence of genetic variability among accessions evaluated and that the accessions interact with the environment resulting in a differential genotypic response.

Leaf Width.
Te interaction efect of earthing-up frequency and variety did not signifcantly afect the leaf width of anchote.However, the main efects of earthing up (p < 0.01) and variety (p < 0.01) had a highly signifcant efect on the leaf width of anchote.Te widest leaf width was observed from earthing up four times (10.29 cm) and earthing up three times (10.26 cm) while the narrowest leaf width was observed from no earthing up (9.24 cm) (Table 4).Tis might be because the active growth stage of the plant is improved by the soil porosity, aeration, better root growth, and penetration for nutrient absorption thereby increasing leaf width for the requirement of metabolic activities.Tis  6 International Journal of Agronomy result agrees with that of Getachew et al. [27], who reported that the largest leaf area was obtained from potato earthing up after complete plant emergence, which coincided with the increased plant growth and development that ultimately increased the leaf area of potato.For variety, the widest leaf width was obtained from Desta 01 (9.97 cm) and Acc405 (9.91 cm) while the narrowest was observed from Acc173 (9.46 cm) (Table 4).Tis result may be due to genetic diferences among the varieties under study.Te result agrees with the fnding of Mengesha et al. [8], who reported that the presence of genetic variability among accessions evaluated and that the accessions interact with the environment resulting in a diferential genotypic response.

Vine Diameter.
Te interaction efect of earthing-up frequency and variety had a signifcant efect (p < 0.05) on the vine diameter of anchote.Te analysis showed that the highest vine diameter was obtained from four times (6.82 mm) and three times (6.80 mm) earthing up with anchote variety Desta 01, while the lowest was recorded from no earthing up with variety Acc173 (3.94 mm) (Table 5).Tis result might be because earthing-up contributed to controlling weeds and increased root penetration that enabled the plant to absorb enough nutrients and water thereby increasing the vine diameter of anchote.Tis is in line with the fnding of Getachew et al. [27] who reported that the earthing-up enabled potatoes to absorb more nutrients and Gebremedhin et al. [29] who also indicated that one-time earthing up increased growth parameters and yield components of potatoes as compared to no earthing up.

Leaf Number per Plant.
Te interaction efect of earthing-up frequency and variety had a highly signifcant efect (p < 0.01) on the leaf length of anchote.Te highest leaf numbers per plant were obtained from earthing up four times (35.36 leaves) and three times (35.18 leaves) with Acc173.Te lowest leaf numbers per plant were observed from no earthing up with Desta 01 (17.82 leaves) and Acc405 variety (18.11 leaves) (Table 5).Tis result is in line with the fnding of Ali et al. [28], who indicated that the number of leaves per plant was observed to vary signifcantly between earthing up and none earthing up in the case of onion.

Shoot Fresh Weight per Plant.
Te interaction efect of earthing-up frequency and variety had a signifcant efect (p < 0.05) on shoot fresh weight per plant of anchote.Te highest shoot fresh weight per plant was recorded from four times earthing up with Acc173 (0.584 kg) and Acc405 (0.583 kg) and three times earthing up with Acc173 (0.57 kg) and Acc405 (0.58 kg) (Table 5).Te lowest shoot fresh weight per plant (0.36 kg) was recorded from the control with Acc405.Tis result agrees with the fnding of Fitsum et al. [12], who reported that the fresh shoot biomass of potatoes was signifcantly afected by earthing up whereas low fresh shoot biomass was recorded from the control.Tis may be because of more leaf number, leaf area, and lateral branches as the result of adequate nutrient and moisture absorption by their root that grew freely.Fitsum et al. [12] also supported this by showing that the more lateral branches and enlarged leaves, the higher the shoot biomass per potato plant as a result of earthing-up.In addition, the author of [2] indicated that the diference in ground coverage of anchote accessions could be due to the diference in soil conditions and varieties.

Shoot Dry Weight per Plant.
Te interaction efect of earthing-up frequency and variety had a signifcant efect (p < 0.05) on shoot dry weight per plant of anchote.Te highest shoot dry weight per plant was recorded four times (0.06 kg) and three times (0.0609 kg) earthing up with Desta 01 (Table 5) while the lowest shoot dry weight per plant (0.04 kg) was obtained from the control with Acc173.Tis indicates that days to maturity were prolonged (up to 4 months) as a result of earthing up, and shoot dry weight increased though it declined after four months of harvesting as an increment of yield components.Tis agrees with the work of Abera and Haile [7], who indicated that anchote produced signifcantly higher fresh and dry above-ground biomass at the 4th month of harvesting date.However, it is also acknowledged that during the following harvesting dates, which are the seventh through the sixteenth month of in situ storage, the biomass of anchote, both fresh and dry, dramatically decreased [7].

Yield and Yield Components
3.3.1.Tuber Fresh Weight per Plant.Te interaction efect of earthing-up frequency and variety had a signifcant efect (p < 0.05) on tuber fresh weight per plant of anchote.Te highest tuber fresh weight per plant was obtained from earthing up four times with Desta 01 variety (0.216 kg) and earthing up three times with Desta 01 (0.215 kg) (Table 6), while the lowest was from control with Acc405 (0.121 kg) and control with Acc173 (0.169 kg).Tis might be because earthing up decreased the soil temperature, facilitated aeration and moisture, and improved root penetration that enabled to increase in tuber fresh weight.Tis is in agreement with the work of Chitsinde [10], who stated that adequate earthing up results in plants having a larger area of root volume, to gain enough water and nutrients for tuber development as compared to control, which has a limited area for water and nutrient extraction needed for photosynthesis.Terefore, due to favorable soil moisture, aeration, and availability of nutrients, there may greater number of leaves, thereby capturing enough sunlight that is used to facilitate tuber growth.Tis result agrees with the fnding of [7], who stated that the greater the number of leaves in a feld, the better the interception of sunlight, and the higher the tuberous root yield.In addition, the highest shoot fresh weight could be due to the genetic variability of anchote as also stated by Mwololo et al. [30], who reported that the weight diference of sweet potato varieties might have come from the genetic capability of the varieties.

Tuber Dry Matter Content per Plant.
Te interaction efect of earthing-up frequency and variety had a signifcant efect (p < 0.05) on tuber dry matter per plant of anchote.Te highest tuber dry matter content per plant was obtained from earthing up four times with Desta 01 (29.382%) and earthing up three times with Desta 01 (29.349%) while the lowest was from control (8.807%) and earthing up once (9.065%) with Acc173 (Table 6).On the other hand, there was no signifcant diference between four times earthing-up frequency for Acc175 and three times earthing-up frequency for Acc405.
Te result showed that the tuber dry matter content was positively and signifcantly correlated with leaf width (r = 0.71), leaf length (r = 0.87), leaf number per plant (r = 0.70), shoot fresh weight per plant (r = 0.48), and shoot dry weight per plant (r = 0.89) (Table7).Zalalem et al. [31] reported that a positive and highly signifcant correlation was observed between above and underground biomass showing the presence of a close connection between them.Tis result revealed that as the result of earthing up, there was an increment of leaf width, leaf length, and leaf number, which increased the amount of solar radiation intercepted and more photoassimilate produced, thereby adequate amount of carbohydrate to translocate to the tuber.Tis result agrees with the fnding of Chitsinde [10], who stated that adequate earthing-up results in plants gaining enough water and nutrients for tuber development because of good photosynthesis in the case of potatoes.According to Zalalem et al. [31] , there was a possible increase in photoassimilate production and translocation to the potato tuber due to the increased total leaf area, which also increased the amount of solar energy intercepted.Besides, tuber in aerated soil accumulated more dry matter content which supports the fnding of [32,33], who stated that the aerated plant had more dry matter due to the root improvement in the case of sweet potato.
Te result also showed that the evaluation of any crop by its limiting factors and any additional value is due to varieties, which agrees with the work of [34], who indicated that diferent dry matter contents are observed even within the same varieties [35,36] and also stated that the wider Means followed by the same letter across columns are not signifcantly diferent at p � 0.05, TFWPP � tuber fresh weight per plant, TDWPP � tuber dry weight per plant, and control � without earthing up.LSD � least signifcance diference and CV � coefcient of variation.International Journal of Agronomy variability in the root of sweet potato varieties is also in agreement with the root traits diversity exhibited in dry matter.

Marketable Tuber
Weight per Hectare.Te interaction efect of earthing-up frequency and variety had a highly signifcant efect (p < 0.01) on marketable tuber weight t ha −1 of anchote (Table 8).Te highest marketable tuber t ha −1 was obtained from earthing up four times with Desta 01 (25.98 t ha −1 ) and three times earthing up with Desta 01 (25.88 t ha −1 ), while the lowest (11.38 t ha −1 ) was from control with Acc405 (Table 8).Te result showed that the earthing up increased the tuber in size and prevented it from being infected by insects because of a decrease in temperature, soil compaction, and exposure to sunlight.In addition, since dry matter content and marketable tuber were positively and signifcantly correlated (r = 0.69) (Table 7), it might be difcult to penetrate insects, and soil has physically buried the tuber, which enabled the tuber to be easily seen by insects.Tis result accepts the work of Getachew et al. [27], who indicated that proper ridging increases tuber yield, by creating favorable conditions for tuber initiation and development.

Unmarketable Tuber
Weight per Hectare.Te interaction efect of earthing-up frequency and variety had a signifcant efect (p < 0.05) on unmarketable tuber weight per plot of anchote.Te highest unmarketable tuber weight per plot was obtained from control with Acc173 (4.59 t ha −1 ), while the lowest was from earthing-up four times (0.96 t ha −1 ) and three times (0.99 t ha −1 ) with Desta 01(Table 8).Nevertheless, all earthing-up frequencies at four times and three times with their corresponding varieties were not statistically diferent.Tis may be because the anchote tuber with no earthing up could be undersized as a result of high temperature and low nutrient released as well as damaged by insects which agrees with the fnding of Getachew et al. [27], who reported that poor earthing up around the plants could expose the tuber to sunlight, high temperature, diseases, and insect damage.In line with this, Chitsinde [10] also reported that when the temperature was increased to 25 °C, the size of tubers formed by the plant also decreased, and this practice was common when the crop was not properly earthed up.In addition, genetic variability and genetic interaction with the environment also infuenced unmarketable tuber yield which confrms the fnding of Taf et al. [37], who indicated the interaction of soil adding to bush and varieties infuences yield components of sweat potato.7).Tis might be because tuber yield was formed and increased as a result of low temperature and earthing up minimized tuber exposure to sunlight, damage by insects, and soil compaction collectively improved the total yield of the tuber.Tis agrees with the work of [38], who reported that tubers formed well when soil temperature was as low as 10 °C to 12 °C permitted tubers formation and development.Tis might be because, at a high temperature above the optimum, the rate of respiration is greater than the rate of photosynthesis, reduces the translocation of carbohydrates to the tuber, and increases the occurrences of diseases around the storage tuber [38] and also concluded that more earthing enables large tubers to be formed on the buried stems in the case of sweat potatoes.In addition, the wider variability in the root of sweet potato varieties is also in agreement with the root traits diversity exhibited in root yield variability, which confrms the work of germplasm collection from Tanzania [33,35].Te correlation analysis also revealed that tuber yield t ha −1 was positively and perfectly correlated with tuber fresh weight per plant (r � 1).Te total yield per hectare was also signifcantly correlated with days 50% to fowering (r � 0.67), days to physiological maturity (r � 0.61), plant height (r � 0.59), vine internode length (r � 0.56), vine diameter (r � 0.69), leaf number per plant (r � 0.47), leaf length (0.58), leaf width (r � 0.45), shoot fresh weight per plant (r � 0.38), shoot dry weight per plant (r � 0.62), tuber dry matter content per plant (r � 0.46), marketable tuber weight per hectare (r � 0.96), and unmarketable tuber weight per hectare (r � −0.43) (Table 7).Tis might be due to the improvement of the considered traits could result in an improvement in tuber yield.Tis confrms the fnding of [39,40], who stated that considerable emphasis should be given to yield and growth traits to increase root yield in anchote.

Cost-Beneft Analysis for Appropriate Earthing-Up
Frequency.Te values of total income vary (309,054.26, 379,824.70, 412,304.54, 476,291.89,and 479,557.39ETB (Ethiopian Birr) ha −1 for control, once, two times, three times, and four times earthing-up frequency, respectively) for diferent levels of earthing-up frequency, while the value of partial costs of anchote production calculated from control, and once and two times earthing-up frequencies were not diferent (180,000 Ethiopian Birr ha −1 ) from each others.Te current result showed that the highest total income was obtained from four times earthing-up frequency (479,557.39ETB ha −1 ) and the lowest was obtained from control (309,054.26ETB ha −1 ) whereas the highest total cost was obtained from four times earthing-up frequency (240,000 ETB ha −1 ).However, the lowest total cost was recorded from control, once, two times, and three times (180,000 ETB ha −1 ) earthing-up frequency.Te highest net beneft was observed from three times earthing-up frequency (296,291.89ETB ha −1 ), while the lowest was recorded from the control treatment (129,054.26ETB ha −1 ).Te above results might be due to diferences in yield recorded by the diferent earthing-up frequency levels much resulting in the highest yield to its production cost which 10 International Journal of Agronomy confrms the work of Omovbude and Udensi [24], who stated that the diferences in yield recorded by the diferent treatments mulch resulting in the highest yield.

Conclusion
Anchote is native to Ethiopia and is the only crop produced for its edible tuberous root from its family Cucurbitaceae.However, its distribution was limited to the western and south-western parts of Ethiopia, since the attempts made so far to improve the genetic and agronomic practice related to the management of the crop are very limited.Tus, the objective of this study was to evaluate the superior yielding variety and earthing-up frequency on anchote to improve the current anchote growth and root yield in the study area with the implementation of optimum earthing-up frequency on diferent anchote varieties.Results of the current experiment revealed that the interaction efects of earthing-up frequency and varieties signifcantly afected anchote leaf number per plant, marketable tuber weight per hectare, shoot dry weight per plant, unmarketable tuber weight per hectare, vine diameter, shoot fresh weight per plant, tuber dry weight per plant, tuber fresh weight per plant, and tuber yield per hectare.Te main efects of earthing-up frequencies and varieties signifcantly infuenced days to 50% fowering, days to 50% fowering, leaf width, and leaf length.Te maximum economical yield was obtained from three times earthing up (26.88 t ha −1 ) with Desta 01 followed by three times earthing up with Acc405 (25.5 t ha −1 ).In conclusion, for the study area, it is better to apply three times earthing-up frequency with Desta 01 variety followed by Acc405.To assure future food security, using the anchote crop will be an alternative opportunity.Tus, comparative attention should be given to this crop, to satisfy the food demand of the population.Te experiment was conducted under irrigation conditions and at one location and season; therefore, it should be repeated under rainfed and at more locations and seasons to assess the further efect of earthing-up frequency on the growth and yield of anchote varieties and come up with a sound recommendation.International Journal of Agronomy

Figure 1 :
Figure 1: Map of the study area.

Table 1 :
Information about the three anchote genotypes/varieties.

Table 2 :
Efect of earthing-up frequencies and varieties on the day to 50% fowering and days to physiological maturity of anchote at Gimbi district, western Ethiopia in 2020/2021.
Means followed by the same letter across columns are not signifcantly diferent at p � 0.05; 50% FD � day to 50% fowering; DFM � day to physiological maturity; control � without earthing up.LSD � least signifcance diference and CV � coefcient of variation.

Table 4 :
Efect of earthing-up frequencies and varieties on leaf length and leaf width of anchote at Gimbi district, western Ethiopia in 2020/2021.
Means followed by the same letter across columns are not signifcantly diferent at p � 0.05, LL � leaf length, LW � leaf width, and control � without earthing up.LSD � least signifcance diference and CV � coefcient of variation.

Table 3 :
Efect of earthing-up frequencies and varieties on plant height and vine internodes length of anchote at Gimbi district, western Ethiopia in 2020/2021.
Means followed by the same letter across the column are not signifcantly diferent at p � 0.05; PH � plant height; VIL � vine internode length; control � without earthing up.LSD � least signifcance diference and CV � coefcient of variation.

Table 6 :
Interaction efect of earthing-up frequencies and varieties on tuber fresh weight per plant and tuber dry matter content per plant of anchote at Gimbi district, western Ethiopia in 2020/2021.

Table 5 :
Interaction efect of earthing-up frequencies and varieties on vine diameter, leaf number per plant, shoot fresh weight per plant, and shoot dry weight per plant of anchote at Gimbi district, western Ethiopia in 2020/2021.Means followed by the same letter across columns are not signifcantly diferent at p � 0.05, VDPP � vine diameter per plant, LNPP � leaf number per plant control � without earthing up, SFWPP � shoot fresh weight per plant, and SDWPP � shoot dry matter content per plant.LSD � least signifcance diference and CV � coefcient of variation.

Table 7 :
Correlation coefcient of the 15 parameters of three anchote varieties grown at Gimbi district, western Ethiopia in 2020/2021.