Macaw palm (Acrocomia aculeata) is native to tropical forests in South America and highly abundant in Brazil. It is cited as a highly productive oleaginous palm tree presenting high potential for biodiesel production. The aim of this work was to characterize and study the genetic diversity of A. aculeata ex situ collections from different geographical states in Brazil using microsatellite (Simple Sequence Repeats, SSR) markers. A total of 192 accessions from 10 provenances were analyzed with 10 SSR, and variations were detected in allelic diversity, polymorphism, and heterozygosity in the collections. Three major groups of accessions were formed using PCoA—principal coordinate analysis, UPGMA—unweighted pair-group method with arithmetic mean, and Tocher. The Mantel test revealed a weak correlation (r = 0.07) between genetic and geographic distances among the provenances reaffirming the result of the grouping. Reduced average heterozygosity (Ho < 50%) per locus (or provenance) confirmed the predominance of endogamy (or inbreeding) in the germplasm collections as evidenced by positive inbreeding coefficient (F > 0) per locus (or per provenance). AMOVA—Analysis of Molecular Variance revealed higher (48.2%) genetic variation within population than among populations (36.5%). SSR are useful molecular markers in characterizing A. aculeata germplasm and could facilitate the process of identifying, grouping, and selecting genotypes. Present results could be used to formulate appropriate conservation strategies in the genebank.

The experiment was conducted at Kulumsa, South East Ethiopia, using four levels of nitrogen (N) (0, 50,100 and 150 kg N ha⁻¹) and four levels of phosphorus (P) (0, 35, 70 and 105 kg P₂O₅ ha⁻¹) fertilizers arranged in 4 × 4 factorial arrangements in randomized complete block design with three replications. The available P was increased after harvest due to the application of N and P fertilizer at the rates of 100 or 150 kg N ha⁻¹ and 70 or 105 kg P₂O₅ ha⁻¹. More specifically, nutrients concentration and nutrient uptake were significantly (p < .01) varied among treatment combinations and nutrient use efficiency was declined by increasing N and P after optimum rates. The higher physiological efficiency of N (53.47 kg kg⁻¹) and P (580.41 kg kg⁻¹) and the highest apparent recovery of N (19.62%) and P (2.47%) was recorded from application of 50 kg N ha⁻¹ and P at 70 kg P₂O₅ ha⁻¹ and the highest agronomic efficiency of N (10.78 kg kg⁻¹) and P (15.25 kg kg⁻¹) was recorded from N at the rate of 50 kg N ha⁻¹ and P at 35 kg P₂O₅ ha⁻¹, respectively. The combination of N at 100 kg N ha⁻¹ and P at 70 kg P₂O₅ ha⁻¹ was promising combination that generated highest net benefit 488,878.5 ETB (Ethiopian birr) ha⁻¹ with the highest marginal rate of return (36638%) and gave the highest seed yield (1858.82 kg ha⁻¹) with yield increment of about 57.72% over the control.

Microsatellites or simple sequence repeats (SSRs) are useful molecular markers allowing for efficient conservation and sustainable use of genetic resources of plant species. Development of SSR marker system for new species is a very expensive task and time consuming. Cross-species amplification of microsatellite loci is considered as a cost-effective approach for developing microsatellite markers for new species. The aim of this work was to examine the transferability of some SSR markers of two Arecaceae species (Astrocaryum aculeatum and Elaeis oleifera), in Acrocomia aculeata. Out of the total markers analysed 44% of the markers successfully amplified the genomic DNA in A. aculeata, of which 26% were polymorphic detecting a range of three to eight alleles with an average of 4.5 per locus. High average percentage of polymorphic loci (P= 71.2%) per provenance was obtained within a range of 57–100% detecting genetic variation in A. aculeata germplasm collections. The polymorphic markers detected a positive inbreeding coefficient (F>0) per locus revealing heterozygote deficiency in the accessions that were analysed. As the cross-amplification was at family level, in which the taxonomic distance is relatively wider between the sources (A. aculeatum and E. oleifera) and the target (A. aculeata) species, the amplification success was relatively low. However, the results are promising and implicated that high cross-amplification success could be achieved at species or genus level in A. aculeata. The markers will contribute towards the domestication of the potential macaw palm through realizing various studies such as population genetics, germplasm characterization, genetic improvement and conservation.

In Ethiopia, the low productivity of garlic is largely due to a shortage of high yielding and stable varieties. To address this issue, thirteen garlic genotypes were evaluated for yield stability and performance across six different environments in central and southeast Ethiopia. The genotypes were analysed using Additive Main effects and Multiplicative Interaction (AMMI) and genotype-by-environment interaction (G × E) methods. Results showed that the genotypes differed significantly for bulb yield performance and morphological traits, with G-020/03 and G-054/03 producing the highest bulb yield with 25.39% and 18.39% yield advantages over the check variety, Kuriftu, respectively. Furthermore, G-020/03 demonstrated better yield stability across most environments, while G-054/03 exhibited specific adaptability. GGE biplot analysis confirmed that these two genotypes were among the three winning genotypes in terms of yield performance and relative stability. Therefore, G-020/03 and G-054/03 have been selected as candidate varieties for release, potentially improving garlic productivity in Ethiopia.

Phytophthora infestans is the major bottleneck in potato production in Ethiopia. Selection of appropriate planting time is highly location specific and the most important subject in rain-fed potato production. However, research recommendation on optimum planting time and fungicide application frequency for high lands area of Arsi (Kulumsa) is lacking. Thus, field experiment was carried out to evaluate the effect of planting time and fungicide application frequency on disease severity, yield and yield components of potato at Kulumsa during main cropping season of 2017. The treatments consisted of four planting time in the months of June and July and four fungicide application frequencies at the rate of 2.5 kg ha-1 of Ridomil Gold M.Z 68% W.P. Treatments were combined in 4 × 4 factorial arrangement and laid out in randomized complete block design with three replicates. Data on disease, tuber yield and yield components were analyzed using Statistical Analysis System Version 9.3. The interaction effect between treatments showed a highly significant (p<0.01) effect on disease incidence and area under disease progress curve and a significant (p<0.05) effect on percent severity index. Early planting in June produced significantly higher number of marketable and total tuber numbers per hill which were progressively reduced in subsequent plantings, whereas delay planting in July resulted in higher number of unmarketable tubers per hill. The interaction between early planting and different fungicide application frequencies gave the highest average tuber weight, marketable and total tuber yield per hectare. Therefore, the combination of early planting in June and twice fungicide application gave the optimum results in the study area. Key words: Disease incidence, fungicide, integrated disease management, potato tuber, production season.

Seed quality is crucial for the success of crop production, as it affects germination capacity, emergence potential, and seedling growth. This study investigated the impact of extended stor-age on the germination capacity, oleoresin and essential oil contents of black cumin seeds from three black cumin varieties in Ethiopia: "Aden", "Dershaye", and "Darbera". Seeds were stored for up to three years, and germination studies were conducted using a Completely Randomized De-sign. Results showed that storage period significantly affected various germination parameters, with a decrease in germination percentage observed with increasing storage period. However, variety and the interaction between storage period and variety had no statistically significant effect on germination percentage. The study also provides valuable insights into the correlations between different germination indices. Additionally, as black cumin seeds age, their oleoresin and essential oil contents decrease across all three varieties. Proper seed storage practices are essential in maintaining the germination potential of black cumin seeds, particularly over ex-tended storage periods. Overall, this study provides insights into the impact of extended seed storage on black cumin seed quality and germination potential, highlighting the importance of proper seed management practices to support sustainable crop production.