Sixteen cultivars (three resistant species and thirteen susceptible cultivars to cochineal insects) were included in the experiment to evaluate their nutritional and chemical compositions and to determine the in vitro digestibility of cladodes of the Opuntia species. Cultivars showed highly significant (p < 0.001) differences in their chemical composition. The cultivars’ content of ash, crude protein (CP), dry matter (DM), organic matter (OM), in vitro dry matter digestibility (IVDMD), in vitro organic matter digestibility (IVOMD), acid detergent fiber (ADF), neutral detergent fiber (NDF) and Cell (cellulose) varied, with ranges of 8.18–22.75%, 3.19–10.40%, 86.40–91.88%, 77.45–91.82%, 68.25–87.3%, 55.81–78.95%, 14.88–26.15%, 29.66–67.05% and 10.99–19.92%, respectively. The ash content showed a significant highly negative correlation with OM (r = −1.00; p < 0.001), IVDMD (r = −0.603; p < 0.001) and DOMD (r = −0.904; p < 0.001), respectively. The Garao, Aloqa and O. robusta var. X11 cultivars showed the highest similarities, as they are found close to the first branch of the dendrogram. In total, 90% of the variation among the nutritional traits was attributed to the first four PCs, with 55.97% to the first two principal components (PCs). The nutritional composition of the resistant species was greater than or equal to the susceptible ones.

In Tigray, northern Ethiopia, prickly pear (Opuntia ficus-indica) is an important crop that serves as a source of seasonal food and income, soil and water conservation, live fencing, and an all-year-round livestock feed. With the intention of increasing the benefits from the crop, an exotic insect, the cochineal (Dactylopius coccus), was intentionally introduced. Nevertheless, the insect has gone wild and caused severe damage to the crop. It has now become a serious threat to the survival of the plant species in the Tigray region. Thus, cactus pear populations and exotic materials were evaluated in the laboratory for their resistance to the insect. The cultivars were tested in 2018 using a complete randomized experimental design with five replications and several plants from three different species of cactus pear: (Opuntia ficus-indica, Opuntia stricta, and Opuntia robusta). Each cladode of the test entries was artificially inoculated with 30 crawlers (mobile first instar) of Dactylopius coccus, less than 24 hours from hatching. Days to first and second molting, days to maturity and number of surviving crawlers on each infested cladode after 7, 14, 21 and 45 days were recorded. The number of crawlers in susceptible species, the weight, size and the relationship between weight and size of insects to the number of crawlers produced were also recorded. There was a highly significant difference among cactus pear species in their resistance to the insect, expressed in terms of the number of surviving crawlers and days to maturity. None of the cochineal crawlers on O. stricta and O. robusta test cultivars were able to reach maturity. On the other hand, most of the cochineal crawlers inoculated on the O. ficus-indica lines were able to reach maturity and produce new offspring. The average period for first instar, second instar, maturity and life cycle of the female cochineal, was 19.4, 15.2, 40.4 and 75 days respectively. Thus, both O. robusta and O. stricta were resistant while all O. ficus-indica lines tested were completely susceptible. Besides, the number of crawlers produced per mature female cochineal was found to have a significant correlation coefficient with the size and weight of individual female cochineal. In areas where O. ficus-indica is challenged by D. coccus, suitable cultivars of O. stricta and O. robusta could perhaps perform the same services that were previously filled by O. ficus-indica.

Cactus pear (Opuntia ficus-indica) is a common plant in Ethiopia/Tigray and is known for its various uses, but the diversity of the cactus pear population in Ethiopia varies according to farmer accounts. Therefore, this study was conducted to determine the genetic diversity of the cactus pear population. Descriptive statistics were applied to the qualitative data using SPSS software to calculate frequency distributions. Principal component analysis (PC) was also performed to analyse the qualitative characteristics. The degree of morphological diversity was expressed as the Shannon–Weaver index (H’). Most of the cultivars in this study exhibited ovoid fruit shapes with shape indices ranging from 0.65 to 0.79. Judging by eigenvalues greater than 1, the total deposit rate for the first four PCs was 76.71%. PC1 was positively associated with the cladode shape, fruit shape, fruit shape index, and cladode shape index. Differences in the frequency distributions of morphological parameters among the districts were detected. The orange pulp colour type of cactus pear was dominant in the lower altitudinal areas while the red pulp colour type was dominant at middle altitudes. At lower altitudes, the shape of the cladodes was more elliptical. The number of glochids per fruit decreased with increasing altitude. The H’ for qualitative features ranged from 0.80 to 1.00. The average H’ values for the six traits were greater in the Tsirae-Womberta collection (0.76) but lower in those of the Saesie district (0.64), followed by the Enderta (0.65) and Gulo-Mekeda districts (0.65). The total H’ values across the altitudinal classes varied from 0.60 for pulp colour and glochids to 0.88 for peelability.

The experiment was conducted during 2010 main cropping season. Four sites of six-row barley growing areas of northern Ethiopia were included in the experiment. Its objective was to estimate the magnitude of genotype x environment interactions and their adaptability in the area. Eight nationally released food barley varieties together with four farmers’ varieties were planted in a randomized complete block design with three replications. According to Eberhart and Rusell’s regression stability analysis, Agegnhu and Shedho were stable genotypes, on the other hand, in Wricke’s ecovalence (wi) stability analysis, genotypes Basso and Trit were more stable in grain yield as their contributions to the GEI sum of squares were the least.

The cactus pear (Opuntia ficus-indica) is a crucial plant in Tigray, northern Ethiopia, widely distributed in arid and semi-arid environments. It serves as a seasonal food, and is used in livestock feed, fencing, soil conservation, and environmental protection. Recently, the cactus pear populations in Tigray have been severely affected by an exotic insect, the cochineal (Dactylopius coccus). It damaged cactus pear populations in the region’s southern, southeastern, and eastern zones. The Tigray war that broke out in November 2020 exacerbated D. coccus infestation. A study was conducted in the eastern zone of Tigray to assess the impact of the armed conflict on the trends of this infestation and propose sustainable management approaches for sustainable cactus pear production in post-war Tigray. Both primary and secondary data were collected and analyzed. The findings revealed that D. coccus infestation significantly increased during the war and in the post-war period, compared to in the pre-war period. The number of districts involved and level of D. coccus infestation of cactus pear populations increased. The rapid spread was attributed to the interruption of pest management activities due to the armed conflict. To mitigate the spread and ensure sustainable cactus pear production, this study recommends different management approaches to manage D. coccus dissemination and sustainably produce cactus pear in the region, including pest prevention, suppression, or eradication.

The cactus pear (Opuntia ficus-indica) is a crucial plant in Tigray, northern Ethiopia, widely distributed in arid and semi-arid environments. It serves as a seasonal food, livestock feed, fence, soil conservation, and environmental protection. Recently, the cactus pear population in Tigray have been damaged by an exotic insect, cochineal (Dactylopius coccus). It damaged the cactus pear populations in the region’s southern, south eastern and eastern zones. The Tigray war that broke out in November 2021 exacerbated D. coccus infestation. A study was conducted to assess the impact of the armed conflict on the trends of D. coccus infestation and forward management approaches for sustainable cactus pear production in post-war Tigray. The study was conducted in the eastern zone of Tigray. Primary and secondary data were collected. The study revealed that D. coccus infestation increased during and post-war compared to the pre-war. The number of districts and level of D. coccus¬ infestation on cactus pear populations increased. The rapid D. coccus spread is attributed to the impact of the armed conflict which halted the pest management practices. Different management approaches are recommended to manage D. coccus dissemination and sustainably produce cactus pear in the region, including pest prevention, suppression, or eradication.