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In Ethiopia using inorganic fertilizer started in the early 1970s. But it still depended solely on urea and DAP. Today, according to ATA and Ministry of Agriculture and Natural Resources K, Zn, B, S, and Cu are in deficit in Ethiopia and Amhara Region as well as in Wag-Lasta areas. But some studies conducted in Wag-Lasta and throughout the region in different crops indicate that these nutrients had no response on crop yields. So, this experiment was conducted in 2017 rain feed cropping season on five farmers' parcels per location to verify the response of sorghum to potassium, zinc, and boron nutrients. The treatments were: NPS, NPSK, NPSZnB, and NPSZnBK, with the recommended rate of 46 and 23 kg ha-1 N and P2O5, respectively for Sekota, 23 kg ha-1 N, and P2O5 for Lasta. Moreover, 150, 1.47, and 0.07 kg ha-1 KCl, Zn, and B, respectively used uniformly in both locations. The experiment was laid out in randomized complete block design (RCBD) with three replications. The collected data were analyzed by SAS software version 9.0. Analysis of variance revealed that the application of potassium, zinc, and boron had no significant effect (P =0.05) on sorghum yield and yield components at all sites. The exchangeable potassium content in the soil of the study sites is above the critical value level. The result disagrees with the soil fertility map which showed more than 98% of potassium deficiency and more than 80% NPSZnB deficiency. Hence, the application of K, Zn, and B nutrients had no yield advantage over the recommended N and P nutrients in the Wag-Lasta areas. Therefore, currently to increase production and productivity of crops in Wag-Lasta areas using of recommended rate of nitrogen and phosphorous with organic fertilizer sources for each district is the best option rather than using K, Zn, and B nutrients. [ABSTRACT FROM AUTHOR]

Wheat row planting has been seen as a good agronomic practice for increasing wheat yields in Ethiopia. To meet this end, Ethiopian government agricultural extension activities are concerned with the promotion and scaling-up of wheat row planting. However, there is shortage of empirical study on the impact of row planting on wheat yield compared to the conventional broadcast planting method in Dawuro zone, southwestern Ethiopia. This study analyzes factors affecting smallholder farmers participation in wheat row planting and its impact on wheat yield, using data collected from 307 wheat farm households in the Mari Mansa district of Dawuro zone, southwestern Ethiopia. Binary logit and propensity score matching techniques were employed for data analysis. The results of logistic regression suggest that the availability of active family labor force, access to agricultural extension, participation in training and field visit days, farmers saving status, participation in off-farm income, education level, and age of smallholder farmers were important determinant factors in influencing adoption of wheat row planting method in the study area. The propensity score -matching results indicate that the mean yield of row-planted wheat was higher by 24.46% compared to the mean yield of conventional broadcast planting methods in the study area. Therefore, there is need to put due attention by the government agricultural extension services and nongovernment agricultural and rural development programs to promote and scale-up wheat row planting practices at smallholder farm level to reduce the current yield gap between row and conventional broadcast planting of wheat in Dawuro zone. [ABSTRACT FROM AUTHOR]

The experiment was conducted during July-November, 2022 at Melkassa and Kulumsa Agricultural Research Center main station under rain fed condition to assess the extent of genetic variability and to identify potential candidate genotypes. A total of 64 small seeded common bean genotypes were evaluated for 18 quantitative traits using 8*8 triple lattice design. The analysis of variance showed that there was highly significant (p<0.01) difference among genotypes for all studied traits at both individual locations. The genotypes variation for seed yield was ranged from 1685.09 kg ha-1 to 4499 kg ha-1 at Melkassa and from 1369.76 kg ha-1 to 4848.38 kg ha-1 at Kulumsa. High PCV and GCV were recorded for total number of seeds per plant, number of fertile pods and total number of pods plant-1 in both locations. Moderate to high value of GCV and broad sense heritability coupled with high GAM were obtained for seed per plant, dry pod yield per plant, fertile pods per plant, seed weight per plant, hundred seed weight and seed yield per hectare in both locations; indicating the importance of those traits in yield improvement of small seeded common bean. G-39, G-27, G-58, G-35, G-29, G-18, G-8, G-61, G-37 and G-33 showed yield advantage from 49% to 88.9% at Melkassa and G-33, G-8, G-4, G-12, G-58, G-11, G-45, G-13, G-36 and G-30 from 16% to 36% at kulumsa over the best standard check G-64. The existed variations implied the possiblity for further improvement of seed yield and atributing traits through utlizing selected potential genotypes and targeted hybridization schemes in breeding programs. [ABSTRACT FROM AUTHOR]

Castor (Ricinus communis L.) locally known as ‘Gulo’ is a species of flowering plants in the spurge family (Euphorbiaceae) which contains a vast number of plants mostly native to the tropics. Castor belongs to a monotypic genus Ricinus and sub-tribe Ricininae. It was initially believed to have four centers of origin: East Africa (Ethiopia), Northwest and South West Asia and Arabian Peninsula, India, and China. However, Ethiopia is considered to be the most probable site of origin because of the presence of high diversity. The overall objective of this research was conducted to test environmental adaptability of castor bean genotypes at wondogenet, Ethiopia. The experiment was conducted at Wondogenet Agricultural Research Center’s (WGARC) on-station testing site during the main cropping season of 2022. Highly significant (P<0.01) differences among varieties were observed in the testing site for days to plant height, number of capsules per plant, number of nods per plant, nod length, number of branches per plant and seed yield per hectare. Caster seed yield for genotypes tested at the tested area ranged from 1114 to 1451.27 kg/ha, and the mean value was 1235.95 kg/ha. The top yielders included Acc#95, Acc#82, and Hiruy, with 1451.27, 1294.03, and 1260.27 kg/ha, respectively. Compared with environmental variance, genetic variance was larger for plant height, number of racem per plants, length of main racem, number of capsuls per plant, number of nodes per plants, node length and number of branches per plants. Therefore, the higher proportion of phenotypic variance observed on these traits was due to the larger proportion of genotypic variance. [ABSTRACT FROM AUTHOR]

Ethiopia is one of the Gum and Resin producing countries with a large potential. Borana pastoralists particularly utilised these resources as a source of revenue. The majority of Ethiopia's gum-resin products are collected from natural oozing. In southern Ethiopia, improved tapping mechanisms are uncommon. This study was conducted to determine the effect of different tapping machines and tapping at different tree diameter classes on the gum and incense yields of selected tree species. Commiphora corrugata, Boswellia microphylla, and Boswellia neglecta tree species were selected for their potential existence and economic importance. A factorial experiment was arranged in a randomised complete block design (RCBD) in which three types of tapping materials including natural oozing and three levels of tree size (diameter classes) were used. Accordingly, materials (Panga, Axe, Sonki, and control) were applied at diameters of (5-8 cm, 8.1-11 cm and >11 cm) for a tree height below DBH (at < 130 cm) and above DBH (at >130 cm) on selected tree species while natural oozing was remained untapped and used as controls. Accordingly, the highest mean yield was recorded for trees tapped by axe (5.99 g/tree), followed by Sonki (5.01 g/tree) and bigger diameter class >11 cm (7.10 g/tree) for Commiphora corrugata. The highest mean yield was also obtained for trees tapped by axe (10.76 g/tree) in the first year and (43.71 g/tree) in the second year and bigger diameter class >11 cm (15.16 g/tree) in the first year and (47.81 g/tree) in the second year for Boswellia microphylla. Moreover, the highest mean yield was recorded for naturally oozing trees (6.16 g/tree) and bigger diameter class >11 cm (6.33 g/tree) for Boswellia neglecta. Tapped trees generally provided significantly higher yields than untapped or control trees, and frankincense yield increased with increasing tree size. [ABSTRACT FROM AUTHOR]

Bread wheat is the world's leading cereal grain, and more than one-third of the world's population uses it as a staple food. The bread wheat production in Ethiopia is low compsssared to the national average yield, mainly due to the lack of high-yielding genotypes. This study was conducted during the 2019-2020 growing season to assess genetic variability and estimate the association of traits among bread wheat genotypes. The experiment consists of 49 bread wheat genotypes and is laid out in 7 × 7 simple lattice designs. The results showed significant differences (p < 0.01) among genotypes for most of the studied traits. Moderate genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) values were estimated for yield plant −1, thousand seed weight, and biomass yield. High heritability coupled with a high GAM was observed for thousand seed weight and yield plant –1. The grain yield showed a highly significant (p < 0.01) correlation with many yield-related traits at the phenotypic and genotypic levels. The biomass yield and the harvest index exerted the highest positive direct effect on grain yield at the genotypic level. The highest intercluster distance was observed between clusters I and IV (D2 = 31.86 ∗ ∗ ), followed by clusters II and IV (D2 = 29.21 ∗), and clusters II and III (D2 = 28.24 ∗), which indicated the chance of selecting a member of these clusters for hybridization. This experiment's result indicates sufficient genetic variability among the tested genotypes, which provides ample scope for selecting superior and desired genotypes. Best-performed genotypes should be included in the future breeding program for further yield improvement. In conclusion, attention should be given to traits with moderate to high heritability and GAM, exerting a positive direct effect on the grain yield. However, the experiment should be repeated over locations and seasons to draw a definite conclusion. [ABSTRACT FROM AUTHOR]

Biochar is a carbon-rich product, which is processed by pyrolyzing biomass to improve soil properties and maintain environmental sustainability. This study aim was to investigate the effect of biochar and inorganic fertilizer on soil properties, growth, and yield. Four treatments and four replications have been used for the experimental plots using Randomized Complete Block Design (RCBD). Soil physiochemical properties have been investigated based on soil samples within 0-30 cm depth in each plot. The two types of biochar (grass and chat waste) have been used for the treatments. The pyrolyzing temperature required for grass and chat waste is 250°C and 1100°C, respectively. The plant height, total yield, and the marketable and nonmarketable yield of onion have been examined. The analysis showed that treatment with grass biochar and inorganic fertilizer had a similar effect on soil properties but chat (Catha edulis) biochar had a lower effect on soil properties. The total yield and days to 70% maturity have been increased due to the cumulative treatment of grass biochar and inorganic fertilizer. The biochar of grass and inorganic fertilizer have been significantly increased in marketable bulb yield, but unmarketable yield becomes decreased. The chat waste and controlled treatments shown an increased unmarketable yield and declined marketable bulb yield. Overall, biochar can substitute the inorganic fertilizer, which can help to improve the w soil fertility and environmental sustainability. Therefore, biochar has a win-win solution. [ABSTRACT FROM AUTHOR]

Garlic (Allium sativum) has for centuries been valued by humans for food, culinary and medicinal purposes world over. The objective of this study was to investigate genetic variability among garlic accessions for yield, yield related and phenology traits in Ethiopia. A field study was conducted at the DebreZeit Agricultural Research Center during 2012, using 49 garlic accessions from the highlands of North Shewa, East and West Arsi, Arsi, Bale and Sidama zones, which are among the major garlic producing areas in Ethiopia. The experiment was arranged in a 7x7 simple Lattice design, with two replications. Accession were highly significant (P < 0.01) for days to maturity, leaf number per plant, neck diameter, yield per plant, biological yield per plant, dry weight above ground, bulb dry weight, dry weight underground, clove number per bulb, and clove weight per bulb. Heritability estimates ranged from 82.48% for clove number, to 6.46% harvest index. High heritability, combined with high genetic advance (as per cent of mean) observed for mean clove number, yield per plant, biological yield per plant and clove weight per plant showed that these characters were controlled by additive gene effects. Thus phenotypic selection for these characters would likely be effective in variety selection and development. Bulb yield per plant had positive and highly significant genotypic and phenotypic correlations, with all characters, except plant height and harvest index. Path analysis at phenotypic level revealed that biological yield and bulb dry weight contributed major positive direct effects to bulb yield per plant. These traits showed positive and highly significant genotypic correlations with bulb yield except harvest index. [ABSTRACT FROM AUTHOR]

Inappropriate spacing is one of the major problems in tomato production at the study area. A field experiment was conducted to determine inter- and intrarow plant spacing for yield and yield components of tomato at Shewarobit, central rift valley of Ethiopia, under irrigation condition. The treatment comprises of three intrarow spacing (20, 30, and 40 cm) and four interrow spacing (60, 80, 100, and 120 cm) replicated three times and arranged in randomized complete block design using tomato variety Weyno. Data collected on fruit yield and yield components were analysed using SAS. The main effect of interrow spacing significantly affected marketable fruit, unmarketable fruit, marketable fruit number, unmarketable fruit number, and fruit diameter. The 20 cm interrow spacing showed a marked increase in marketable fruit yield by 35.96% as compared to 30 cm spacing used by farmers. Planting tomato in closer interrow spacing (60 cm) resulted in 50% yield increment than the widest (120 cm) space between rows. Interaction effects of both inter- and intrarow spacing significantly (p < 0.05) affected plant height and fruit length. An intrarow and interrow spacing of 20 ∗ 100 cm and 20 ∗ 120 cm resulted in tallest plants and widest fruits, respectively. Therefore, farmers can use 20 cm intrarow spacing and 60 cm interrow spacing for planting of tomato seedling of Weyno variety. [ABSTRACT FROM AUTHOR]

Faba bean (Vicia faba L.) is an important cool-season legume crop that ranks fourth after chickpea (Cicer arietinum L.), field pea (Pisum sativum L.) and lentil (Lens culinaris L.) in terms of total production. The global production of faba bean was 4.8 Mt in 2017, with China, Ethiopia and Australia being the largest producers (1.8, 0.93 and 0.37 Mt, respectively). However, its area of production is not increasing relative to other crops, mainly because of high yield instability. This can be attributed to several factors related to plant traits (e.g. phenology, morpho-physiology) and biotic and abiotic stresses. Faba bean has a very poor flower : pod ratio, with a maximum 20% of flowers resulting in pods. Environmental stresses such as frost, heat and drought cause significant damage to flowers and young pods; therefore, matching phenology of crops to the environment is important for avoiding or minimising detrimental effects of unfavourable environmental conditions. In order to improve adaptation and yield, we need to understand the main factors affecting plant growth, including biotic stresses, identify the main yield components, and find traits associated with tolerance to frost, heat and drought. Yield instability is a major issue in faba bean and is driven by plant traits and biotic and abiotic stresses. The present article reviews the main factors affecting plant yield, the most important yield components, the effect of environmental stresses (particularly low-temperature stress), and the role of sowing date in improving adaptation and yield in faba bean. [ABSTRACT FROM AUTHOR]

Fourteen common bean (Phaseolus vlgaris L.) varieties that were released in Ethiopia from 1997 to 2012 were evaluated as large-seeded food type common bean varieties with the specific objectives to: (1) estimate the genetic progress made in 15 years of common bean breeding in Ethiopia; (2) assess changes in associated traits in the genetic improvement of common bean varieties released in Ethiopia; and (3) assess the reaction of common bean varieties to bean anthracnose [Clletotrichum lindemuthianum (Sacc. & Magnus) Briosi & Cavara]. The study was conducted at two locations, Bako and Gute during 2014/2015 main cropping season in a randomized complete block design (RCBD) with three replications. Days to 50% flowering (DF), Days to 90% maturity (DM), Grain filling period (GFP), Hundred Seed weight (HSW), Biomass yield (BMY), Grain yield per plot (GY), Harvest index (HI), Biomass production rate (kg/ha/day), Seed growth rate (kg/ha/day), Grain yield per day (kg/ha/day) and Anthracnose (1-9) scale data were collected on plot basis and Plant height, Number of pods per plant, Number of seeds per pod, Number of seeds per plant and grain yield per plant data's were collected on plant basis. Statistical data analyses were performed for biomass yield, grain yield, seed weight, harvest index and bean anthracnose severity. Combined analysis of variance showed highly significant differences among the common bean varieties and between test environments for hundred seed weight. The VXL interaction of seed weight did not show significant difference among the varieties. Regression analysis of mean performance at both environments on year of varietal release showed positive relationship for seed weight (r = 0.08), biomass yield (r = 0.04) and anthracnose disease severity (r = 0.10) but negative relationship for grain yield (r = -0.38), and harvest index (r = -0.37). The highest overall locations mean average of grain yield was 2679.5 kg ha-1 for Ayenew and the lowest was 1050.2 kg ha-1 for GLP-2, the grand mean being 1806 kg ha-1. The annual rates of genetic progresses were 12.7 kg ha-1 (0.13% ha-1 year- 1), -48 kg ha-1 (-0.39%), 0.68 g 100 seed-1 year-1 (0.34% 100 seed-1 year-1), -0.004% and 0.39% for biomass yield, grain yield, seed weight, harvest index and anthracnose disease severity, respectively. Generally, the grain yield was reduced in the period of genetic improvement, due to the consistent performance of the reference variety Gofta. Stepwise regression indicated that grain yield day-1 (82.5%) and days to mature (21.8%) explained more for the variation of grain yield; but, seed size (-40.2%) was more important cause for grain yield reduction than bean anthracnose (-9.3%). The yield of large seeded food type common bean varieties were reduced due to anthracnose and its large seeded for the last fifteen years (1997- 2012) of breeding; in future also managing the disease; especially, anthracnose disease will be the crucial and Ayenew (26.79.5 kg ha-1), Gofta (2627.1 kg ha-1) and Fedis (2180.6 kg ha-1) will be recommended for the area. [ABSTRACT FROM AUTHOR]

Fourteen common bean (Phaseolus vlgaris L.) varieties that were released in Ethiopia from 1997 to 2012 as large-seeded food type common bean varieties were evaluated with the specific objectives to: (1) estimate the genetic progress made in 15 years of common bean breeding in Ethiopia; (2) assess changes in associated traits in the genetic improvement of common bean varieties released in Ethiopia; and (3) assess the reaction of common bean varieties to bean anthracnose [Clletotrichum lindemuthianum (Sacc. and Magnus) Briosi and Cavara]. The study was conducted at two locations, Bako and Gute during 2014/2015 main cropping season in a randomized complete block design (RCBD) with three replications. Days to 50% flowering (DF), Days to 90% maturity (DM), Grain filling period (GFP), Hundred Seed weight (HSW), Biomass yield (BMY), Grain yield per plot (GY), Harvest index (HI), Biomass production rate (kg/ha/day), Seed growth rate (kg/ha/day), Grain yield per day (kg/ha/day) and Anthracnose (1-9) scale data were collected on plot basis and Plant height, Number of pods per plant, Number of seeds per pod, Number of seeds per plant and grain yield per plant data's were collected on plant basis. Statistical data analyses were performed for biomass yield, grain yield, seed weight, harvest index and bean anthracnose severity. Combined analysis of variance showed highly significant differences among the common bean varieties and between test environments for hundred seed weight. The VXL interaction of seed weight did not show significant difference among the varieties. Regression analysis of mean performance at both environments on year of varietal release showed positive relationship for seed weight (r = 0.08), biomass yield (r = 0.04) and anthracnose disease severity (r = 0.10) but negative relationship for grain yield (r = -0.38), and harvest index (r = -0.37). The highest overall locations mean average of grain yield was 2679.5 kg ha-1 for Ayenew and the lowest was 1050.2 kg ha-1 for GLP-2, the grand mean being 1806 kg ha-1. The annual rates of genetic progresses were 12.7 kg ha-1 (0.13% ha-1 year-1), -48 kg ha-1 (-0.39%), 0.68 g 100 seed-1 year-1 (0.34% 100 seed-1 year-1), -0.004% and 0.39% for biomass yield, grain yield, seed weight, harvest index and anthracnose disease severity, respectively. Generally, the grain yield was reduced in the period of genetic improvement, due to the consistent performance of the reference variety Gofta. Stepwise regression indicated that grain yield day-1 (82.5%) and days to mature (21.8%) explained more for the variation of grain yield; but, seed size (-40.2%) was more important cause for grain yield reduction than bean anthracnose (-9.3%). It could, thus, be concluded that the yield of large seeded food type common bean varieties were reduced due to anthracnose and its large seeded for the last fifteen years (1997- 2012) of breeding; in future also managing the disease; especially, anthracnose disease will be crucial and Ayenew (26.79.5 kg ha-1), Gofta 2627.1 kg ha-1) and Fedis (2180.6 kg ha-1) are recommended for production in the study areas. [ABSTRACT FROM AUTHOR]

Sesame (Sesamum indicum L.) is one of the chief foreign exchange earning oil crops in Ethiopia. However, its productivity remains low due to lack of appropriate agronomic practices. The aim of this research was to study the effect of organic mulches on sesame productivity and in situ moisture conservation. This experiment was carried out in Humera Agricultural Research Center, Western Tigray, during 2015 growing season. The experimental design was Randomized Complete Block Design with three replications. There were four types of organic mulches; rice straw, sorghum straw, sesame straw, and Sudan grass were compared with control. Sesame, variety Setit-1 was used in the experiment. The organic mulching rate of application was 10 ton ha−1 and this was applied evenly to the soil immediately after germination. Soil water content, phonological characteristics yield, and yield components of sesame were collected. The analyzed results indicated that organic mulching had significant effect on soil moisture content at 0–0.2 m, 0.21–0.4 m, and 0.41–0.6 m in every two-week interval after sowing and grain yield of sesame. Sesame straw conserved highest soil moisture content as compared with respective mulch material. The highest yield (664 kg ha−1) was recorded with Sudan grass while the lowest grain yield (190 kg ha−1) was recorded with no mulch. [ABSTRACT FROM AUTHOR]

• Cutting once after growing season significantly promoted biomass yields of herbaceous vegetation and grass. • Cutting every 3 weeks favored non-grass diversity and both non-grass and herbaceous richness. • Subsequent cutting across years significantly promoted grass composition & biomass. • Continuous cutting over years markedly affected non-grass composition & density. • Herbaceous vegetation nutritional values markedly varied among functional groups. Herbaceous vegetation species' responses to cutting frequencies have not been evaluated in the Borana rangelands, southern Ethiopia. The current study was investigated to determine the grass and non-grass species' yield responses to four cutting frequencies over two years (2019 and 2020). The four treatments were cutting once after the end of the main growing season (T1), cutting every week (T2), cutting every-two weeks (T3), and cutting every-three weeks (T4). Treatments were arranged in a randomized complete block design with four replications. In total, 37 different herbaceous species comprising 15 grasses and 22 non-grasses were sampled. Treatments had a significant effect (p < 0.01) on herbaceous biomass with yield decreasing as the number of cutting frequencies increase. Herbaceous species richness was significantly (p < 0.05) high for T4. Grass biomass was significantly (p < 0.001) high for T1. T4 markedly (p < 0.05) favored non-grass species richness and diversity while T3 significantly (p < 0.05) promoted density. Subsequent cutting over years significantly (p < 0.05) affected grass species composition and biomass. Continuous application of more frequent cuttings over years significantly (p < 0.05) favored non-grass species composition and density. Of the herbaceous vegetation attributes studied, only biomass was significantly (p < 0.05) affected by subsequent application of cutting frequencies over years being high for less frequent cutting (T1). Furthermore, T1 enhanced the percentages dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) of both grass and non-grass species. T2 favored the percentage of crude protein and true in-vitro organic matter digestibility for grass and non-grass species. Our study outlines that intermediate cutting (T4) had a positive effect on herbaceous vegetation attributes and forage nutritional qualities. Hence, for short-term rangeland management in terms of plant yield and better quality, cutting every-three weeks (intermediate cutting) will be suggested when applied subsequently over years. [ABSTRACT FROM AUTHOR]

• We examine inter- and intra-plot heterogeneity of productivity in maize plots. • We find high inter- and intra-plot variabilities in plant population and yield. • Intra-plot heterogeneity overrides inter-plot heterogeneity in smallholder maize. • The magnitude and distribution of yield estimation errors are method-dependent. • More intensively managed plots show lower intra-plot heterogeneity and lower yield. Intra-plot heterogeneity in yield is often observed in smallholder farming systems, although its implications for yield measurement remain under-investigated. Using a unique dataset on smallholder maize production in Ethiopia, we quantify the magnitude of inter- and intra-plot heterogeneity, describe the relationship between intra-plot heterogeneity and maize productivity, and document the implications of intra-field heterogeneity on the accuracy of alternative yield estimation protocols. Our data include five common yield estimation protocols, as well as full plot harvests of 230 smallholder maize fields. We surveyed agronomic decisions, biophysical variables, and accessibility characteristics of the surveyed fields. We quantify intra-plot heterogeneity using the coefficient of variation (CV) of stand density, cob weight, and maize grain yield. A generalized linear mixed model is used to explore the relationship between these variables and the method- and heterogeneity-dependence of yield estimation accuracy. We find inter-plot CV values ranging from 32 to 56 %, 22 to 73 % and 39 to 49 % in population density, cob weight and grain yield, respectively. Intra-plot heterogeneity constituted most of this variation, with across-method mean CV values of 41 %, 82 % and 63 %, respectively, of the total variability in population density, cob weight and grain yield. A rise in intra-plot heterogeneity of 0.5 % to 0.8 % is associated with a significant increase in yield estimation error under alternative yield estimation protocols. Regression analysis shows that interactions in agronomic decisions, input intensity and plot accessibility factors dictate intra-plot heterogeneity and method accuracy in smallholder systems. Intra-plot heterogeneity is larger than inter-plot heterogeneity in the current study area. Our analysis shows that the effect of intra-plot heterogeneity on yield estimation accuracies is method-dependent and yield estimation methods that fail to capture true intra-plot heterogeneity are more error-prone. Results of such estimations should be considered with caution when used as the basis of decision-making. [ABSTRACT FROM AUTHOR]

In the article titled "Effect of Plant Spacing on Yield and Yield Components of Tomato ( I Solanum lycopersicum i L.) in Shewarobit, Central Ethiopia" [[1]], author Hailay Gebremedhin was affiliated to "Department of Horticulture, College of Agriculture and Environmental Sciences, Debre Berhan University, P.O. Box: 50, Debre Berhan, Ethiopia", which is incorrect. The correct affiliations for this author are as follows: SP 2 sp Department of Horticulture, College of Agriculture and Environmental Sciences, Adigirat University, P.O. Box: 50, Adigirat, Ethiopia. REFERENCES 1 Amare G., Gebremedhin H. Effect of plant spacing on yield and yield components of tomato (Solanum lycopersicum L.) in Shewarobit, Central Ethiopia. [Extracted from the article]