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Abstract Nitrogen stress is one of the key factors limiting sorghum crop productivity. To identify desirable sorghum genotypes best suited to nitrogen stress, the response of 300 sorghum landraces and two standard checks: KS78, and BCK60 were evaluated using yield-based indices. The experiment was conducted under nitrogen stress and ideal conditions for two years using a split-plot in RCBD design with two replications. Nitrogen treatments were assigned to the main plots, and sorghum genotypes were assigned to the subplots. Fourteen nitrogen stress screening indices, namely, the yield stability index (YSI), stress tolerance index (STI), modified stress tolerance index (KSTI), low nitrogen tolerance index (LNTI), relative decrease in yield (RDY), tolerance index (TOL), yield index (YI), stress susceptibility index (SSI), stress susceptibility percentage index (SSPI), and harmonic mean (HM), were computed using grain yield. The yield under optimal and stress conditions was significantly positively correlated with the HM, MP, GMP, STI, HM, YI, and modified STI. The results from the cluster analysis, PCA biplot, and 3D biplot classified the genotypes into three groups: nitrogen stress tolerant, nitrogen stress susceptible, and poor performers under both environments. Using STI, GMP, and MP, Genotypes (G80) ETSL101255, (G216) ETSL101006, (G35) ETSL101258, (G146) ETSL100813, and genotypes (G244) ETSL100292, (G161) ETSL100539, (G240) ETSL100890, (G93) ETSL101845, (G261) ETSL100625, (G248) ETSL100874, (G258) ETSL100752, (G142) ETSL100921, (G135) ETSL100307 were identified as top nitrogen stress tolerant, and susceptible genotypes respectively. We conclude that the indices MP, GMP, and STI can help in improving sorghum yield by selecting nitrogen efficient genotypes.

AbstractEthiopia is rich in durum wheat diversity; however, national average productivity of durum wheat is low due to lack of strong national research program, and these calls for development of improved new varieties. Knowledge on extent of genetic variability and identification of important characters are a prerequisite for the development yielder and quality variety. Therefore, the present study was carried out to assess the extent of genetic variability and character association among yield and yield related traits in selected Ethiopian durum wheat landraces. Forty nine durum wheat accessions were studied for 20 traits at Sinana and Selka locations by using 7 × 7 simple lattice design in 2018/19. Combined analysis of variance revealed significant differences among accessions for all traits, indicating the presence of considerable variability among genotypes. A significant accession by locations interaction effect was observed which indicates differential performance of genotypes over environments. Protein content varied from 10.7%–16.7% with the overall mean of 13.5%. Also phenotypic coefficients of variation (PCV) ranged from 2.93 for hectoliter weight (HLW) to 27.08 for productive tillers (PTL) while, genotypic coefficients of variation (GCV) ranged from 0 for wet gluten (WGL) to 16.43 for vitreous (VTR). Low to high heritability was observed for the studied traits. Similarly, genetic advance as percent of mean varied from −0.20–31.24. High broad sense heritability and high genetic advance were obtained for grain yield (GY) (86.57 and 31.24) and vitreous (VTR) (75.76 and 29.39), respectively, indicating traits could be improved easily through selection. Overall, the present study revealed that there is sufficient variability existed in Ethiopian durum wheat landraces.

Abstract Maize production and productivity are affected by biotic and abiotic factors. Among the biotic factors, fungal diseases incited by common leaf rust (CLR) and turciccum leaf blight (TLB) are the most important foliar diseases of the crop in Ethiopia. A field experiment was conducted at Haramaya University, research station “Raare,” during the 2019/2020 main cropping season. The objectives of the study were to investigate the effect of host resistance and fungicide application on the epidemic development of CLR and TLB, yield and yield components of maize, and the management of these foliar diseases. Four maize varieties (Afranqalloo, Bate, Gibee‐3, and Raare‐1) and Mancozeb at four different rates (0, 1.5, 3.0, and 4.5 kg ha−1) were evaluated under field conditions against the diseases. The treatments were laid out in a factorial arrangement in a randomized complete block design with three replications. All disease and agronomic data were collected during the experimental season. The results from analysis of variance showed that the combination of the variety Bate with Mancozeb at a rate of 4.5 kg ha−1 proved to be the best treatment combination for managing both diseases. Similarly, Mancozeb at a rate of 4.5 kg ha−1 resulted in the lowest CLR and TLB disease incidence and severity (60.4% and 21.0%; 63.7% and 41.78%), respectively. Likewise, the highest grain yield (8392 kg ha−1) and thousand kernel weights of 529 g and the lowest epidemic development were recorded from the variety Bate treated with 4.5 kg ha−1 Mancozeb. The result also revealed that the integration of host resistance (the variety Bate) with 4.5 kg ha−1 Mancozeb was the most effective treatment in reducing CLR and TLB epidemic development and in increasing the grain yield of maize. The economic analysis also showed the presence of the highest marginal rate of return from the Bate variety treated with 4.5 kg ha−1 Mancozeb compared to other treatment combinations. Thus, it is concluded that the variety Bate treated with 4.5 kg ha−1 Mancozeb can be used to improve maize production and productivity in the study area and elsewhere with similar agroecologies.

Abstract Common leaf rust (CLR) and turcicum leaf blight (TLB) are the key foliar diseases of maize in Ethiopia. However, in Eastern Ethiopia, information related to the distribution and abundance of CLR and TLB and the relationship of the diseases with independent variables are lacking. Therefore, this study was initiated with the objectives of assessing the distribution of CLR and TLB and their association with biophysical factors and cropping systems. A survey was conducted in the 2019 cropping season in different agroecological zones of East and West Hararghe zones and a total of 120 fields were surveyed. For each field assessed, disease parameters and information on cropping system were recorded. Data were analyzed by using the SAS GENEMODE procedure. Result showed that CLR incidence ranged from 16.84% to 100% in Kombolcha and Kuni districts, respectively. The severity level ranged from 6.0% for Kombolcha to 58.2% for Kuni and Chelenko districts. However, the TLB incidence ranged from 13.4% to 100% at Kobo and Haramaya districts, respectively. Similarly the severity level ranged from 6.0% to 58.0% at Kombolcha and Kuni districts, respectively. Result also showed the presence of higher values of CLR incidence, and severity (>61.7% and >32.1%, respectively) and higher level of TLB incidence and severity (>58.1% and >30.2%, respectively) were highly associated with the West Hararghe Zone, Altitude >2000 m.a.s.l., Kuni and Haramaya districts, fields without any type of fertilizer, un weeded fields, intercroped with sorghum, maize verities sown in June, and seeds collected from previous yield resulted in the highest disease incidence and severity. Among the independent variables, district was the most important variable in its association with CLR incidence (χ2 = 647.93 and 341.18, 7 df) and severity (χ2 = 219.56 and 112.83, 7 df) and with TLB incidence (χ2 = 758.91 and 350.03, 7 df) and severity (χ2 = 330.92 and 124.04, 7 df) when entered first and last into the logistic regression model, respectively. Hence, it is concluded that CLR and TLB are the most widely distributed and important foliar diseases of maize in the Hararghe highlands. Information from this study is very useful to maize growers to device an ecologically sound, and effective management options against these diseases in the study are and elsewhere where the diseases are common and prevalent.

Efficient maize-faba bean intercropping system for optimum grain yield and productivity is needed in order to use the limited land and to enhance food security of the smallholder farmers. A field experiment was conducted at Haramaya, eastern Ethiopia during the 2018 and 2019 main cropping seasons to determine the effect of variety and spatial arrangement on a maize-faba bean intercropping system on yield components and yields of the component crops and the productivity of the system. The treatments consisted of the recommended 100% plant populations of maize (Baate) variety intercropped with 50% of the recommended density of four faba bean varieties (Yeferenji Baqela, Yehabesha Baqela, Batte and Gachena). The component crops were sown at three levels of spatial arrangements (1:1 1:2 and 2:2), whereas sole maize and the four faba beans were sole-planted. The treatments were laid out as a randomized complete block design with three replications in factorial approach. The results revealed that cropping season affected all the maize variables-cropped. Sole-cropped maize gave the higher grain yield (5.91 t ha−1) compared to intercropping system. Maize intercropped with 2:2 spatial arrangements gave the highest grain yield (5.37 t ha−1). Sole-cropped faba bean gave higher seed yield (2.04 t ha−1) than intercropped faba bean. The 1:1 spatial arrangement was superior in number of pods per plant (5.27), aboveground dry biomass (3.81 t ha−1), and seed yield (0.86 t ha−1) to the other spatial arrangements. Variety Gachena was superior to the other varieties in number of pods per plant (5.49), above ground dry biomass (3.77 t ha−1), seed yield (0.88 t ha−1). Land equivalent ratio (LER) was unaffected by variety differences; however, a 26.8% yield advantage was achieved at 1:1 spatial arrangement in which the highest LER (1.268) value was obtained. The highest gross monetary value (GMV) (96,308 ETB ha−1), maize equivalent yield (MEY) (6420.53 kg ha−1) and monetary advantage index (MAI) (17,506) was obtained from Gachena variety. A 1:1 spatial arrangement gave the maximum GMV (94,162 ETB ha−1), MEY (6277.49 kg ha−1) and MAI (18,761). Therefore, it is concluded that intercropping of Gachena variety in a 1:1 spatial arrangement with maize resulted in the highest productivity and economic advantage for the farmers of the study area.

Abstract Cowpea is one of the most important grain legumes for human consumption and animal feeding. Despite this importance, its production is hampered by biotic and abiotic constraints. Genotype by environment interaction study was performed to identify the most stable cowpea genotype(s) and the desirable environment(s) for cowpea research in Ethiopia. Twenty‐four cowpea landraces and one standard check were evaluated for grain yield and yield‐related traits at six locations (Sekota, Kobo, Sirinka, Melkassa, Mieso, and Babile) using 5 × 5 triple lattice during 2019. Combined analysis of variance showed that grain yield was significantly affected by environments, genotypes, and GE interactions. AMMI analysis revealed the contribution of environment, genotype, and GEI for 29.79%, 15.6%, and 42.06% of variation on grain yield. The first two principal components explained 57.97% of the total GEI variance. AMMI model selected G24 as 1st and 2nd best genotype at five environments. The polygon view of the GGE biplot identified three mega‐environments (ME1, ME2, and ME3) with winning genotypes: G24, G3, and G16, respectively. The highest productive (2528.8 kg ha−1) environment, miesso has been identified as the most; discriminating and representative testing environment whereas the lowest productive (1676.1 kg ha−1) Sirinka was the least discriminating and representative. The highest yielder G24 (2632 kg ha−1) was identified as the “ideal” and the most stable genotype followed by G16 (2290 kg ha−1) while the least stable and low yielder was G11. Therefore, genotypes G24 and G16 were recommended for verification and commercial production in most cowpea growing areas of Ethiopia.

Twenty-five common bean genotypes were evaluated to assess the genetic variability, trait association, and determine the direct and indirect effects of traits on seed yield. The genotypes were grown in a lattice design at the research farm of the Melkassa Agricultural Research Center, Melkassa and Miesso, in the 2018 cropping season. Analysis of variance revealed that significant differences were observed among the genotypes at individual locations. The phenotypic coefficient of variation values were moderate for number of nodes, seeds per pod, plant height, and hundred seed weight at Melkassa. Moderate genotypic coefficient of variation values were obtained for pods per plant and seeds per pod. At Miesso, moderate phenotypic coefficients of variation values were recorded for number of nodes, hundred seed weight, and plant height. High heritability estimates were obtained for seed yield and hundred seed weight at Melkassa and for seed yield at Miesso, indicating that selection could be fairly easy and improvement is possible using these traits in a common bean breeding program. High genetic advances were obtained for seed yield and pods per plant at Melkassa, while moderate genetic advances as a percent of the mean were attained for plant height, hundred seed weight, and seeds per pod. Similarly, at Miesso, high and moderate genetic advances as percent of mean values were obtained for seed yield and hundred seed weight, respectively. Seed yield showed positive and significant phenotypic association with days to flowering, internode length, and pods per plant at Melkassa and had positive and significant phenotypic association with seeds per pod and hundred seed weight at Miesso. Hence, selection of those genotypes based on the traits with high genotypic coefficient of variability, heritability, genetic advance, and positive correlation coefficient and direct effect on seed yield can be recommended for further yield improvement at the respective location and at the national level in general.

Maize (Zea mays)-faba bean (Vicia faba) intercropping is a recent practice in eastern Ethiopia and there is limited information on optimum planting density and suitable varieties of faba bean for productive intercropping with maize. Therefore, a field experiment was conducted in eastern Ethiopia during the 2018 and 2019 main cropping seasons to determine the effects of variety and density of faba bean on the yield components of the crops and the productivity of the intercropping. Treatments consisted of three farmers’ varieties (Yeferenji Baqela, Yehabesha Baqela, Batte) and one improved variety (Gachena)intercropped with maize in an additive design at three plant densities (25%, 50%, and 75% of their recommended sole crop density of 250,000 plants ha−1) and the recommended 100% plant density of sole faba bean and sole maize. A randomized complete block design in a factorial arrangement of treatments replicated three times per treatment was used. Analysis of data revealed that sole maize produced a significantly higher number of ears per plant (1.70), thousand kernel weight (287.9 g), aboveground dry biomass (19.11 t ha−1) and grain yield (6.16 t ha−1) than intercropped maize. Among the intercropping systems, maize intercropped with 25% of the sole faba bean produced a significantly higher grain yield (5.56 t ha−1) than 50% and 75% plant density. Similarly, the 75% plant density of the sole faba bean intercropped with maize produced the highest grain yield (0.96 t ha−1) compared to the 25% and 50% plant densities. Faba bean planted in the sole system produced a significantly higher seed yield (2.08 t ha−1) than the intercropped faba bean with maize. Faba bean variety Gachena was found to be superior than the other varieties in number of pods per plant (10.23), aboveground dry biomass (3.73 t ha−1), grain yield (1.96 t ha−1) and harvest index (26.75%). Land equivalent ratio showed 18.4% higher yield advantage when maize was intercropped with faba bean than when it was sole-cropped. The highest gross monetary value (99318 Ethiopian Birr ha−1) and maize equivalent yield (6621.2 kg ha−1) were obtained from maize intercropped with Gachena faba bean variety with no significant differences among the plant densities. It is concluded that intercropping of maize with 75% plant density of improved Gachena variety resulted in superior performance of the system in terms of productivity and economic return.

The study was conducted to estimate the effects of genotype, environment, and genotype × environment interaction on grain yield and yield-related traits and to identify stability genotype. At six environments, twenty-four cowpea landraces and one check were evaluated in a 5 × 5 triple lattice during the 2019 cropping season. Data were collected on yield and yield-related traits. The analysis of variance for each environment and across environments showed significant differences among genotypes, environments, and GEI for most traits including yield. Environment, genotype, and GEI showed 27.45%, 20.9%, and 49.55% contribution to the total sum of squares, respectively, for grain yield. This indicated that the environments were diverse and most of the variation in grain yield was caused due to interaction and environmental means. G24 (2632 kg ha−1) and G16 (2290 kg ha−1) were the highest yielder and stable genotypes with mean grain yields above the grand mean (2049.28 kg ha−1) and standard check (2273 kg ha−1). G24 and G16 were the most stable genotypes according to cultivar superiority, Wricke’s ecovalence, regression coefficient, and devotion from regression stability models.

Identifying yield and grain plumpness QTL that are independent of developmental variation or phenology is of paramount importance for developing widely adapted and stable varieties through the application of marker assisted selection. The current study was designed to dissect the genetic basis of yield performance and grain plumpness in southern Australia using three doubled haploid (DH) populations developed from crosses between adapted parents that are similar in maturity and overall plant development. Three interconnected genetic populations, Commander x Fleet (CF), Commander x WI4304 (CW), and Fleet x WI4304 (FW) developed from crossing of Australian elite barley genotypes, were used to map QTL controlling yield and grain plumpness. QTL for grain plumpness and yield were analysed using genetic linkage maps made of genotyping-by-sequencing markers and major phenology genes, and field trials at three drought prone environments for two growing seasons. Seventeen QTL were detected for grain plumpness. Eighteen yield QTL explaining from 1.2% to 25.0% of the phenotypic variation were found across populations and environments. Significant QTL x environment interaction was observed for all grain plumpness and yield QTL, except QPlum.FW-4H.1 and QYld.FW-2H.1. Unlike previous yield QTL studies in barley, none of the major developmental genes, including Ppd-H1, Vrn-H1, Vrn-H2 and Vrn-H3, that drive barley adaption significantly affected grain plumpness and yield here. Twenty-two QTL controlled yield or grain plumpness independently of known maturity QTL or genes. Adjustment for maturity effects through co-variance analysis had no major effect on these yield QTL indicating that they control yield per se.