Nitrogen use efficiency (NUE) is a key trait for sustainable maize production, balancing high yield performance with reduced environmental impacts associated with nitrogen (N) fertilization. This study assessed the agronomic, physiological, and molecular responses of diverse maize populations under different nitrogen input levels. Nitrogen availability significantly affected grain yield, biomass accumulation, total nitrogen uptake, and nitrogen use efficiency, with significant genotype × nitrogen interactions revealing contrasting adaptive responses among maize populations. In particular, population P13 emerged as a promising candidate, exhibiting stable grain yield under low N conditions, high N uptake efficiency, and superior photosynthetic performance, suggesting strong adaptation to N stress when compared to P11, low efficiency. Gene ontology (GO) enrichment analysis revealed significant modulation of genes involved in ion transport, photosynthesis, and stress responses. Notably, hub genes within the turquoise module of the co-expression network were positively correlated with NUE and included ZmNRT2.7, involved in vacuolar nitrate export, and ZmNDH-B3, contributing to photosynthetic electron transport. The strong expression of these genes in P13 suggests a molecular basis for its superior NUE. These findings underscore the potential of integrating phenotypic screening and transcriptomic approaches to uncover key mechanisms underlying NUE for breeding programs with enhanced nitrogen efficiency, ensuring both high productivity and environmental sustainability in low-input agricultural systems.
Conserving and managing African animal genetic resources requires understanding how these resources evolve (political, environmental, cultural, and social). Factors associated with this context are unfavorable for sound conservation and management in most African countries. This chapter presents the major threats to indigenous animal genetic resources (Sect. 25.2) in Africa; the in situ and ex situ conservation methods practiced (Sects. 25.3 and 25.4), operational guidelines (Sect. 25.5), and the opportunities presented by modern technologies (Sect. 25.6). More research structures and skills in reproductive biotechnology and genetics are needed in the continent to ensure the sustainability of animal resources, in particular those with low numbers or less economic interest. Some African countries with constituted herds for conservation (ex situ in vivo) have also taken the initiative to generate gametes, embryos, tissue, and DNA banks. The multi-stakeholder breeders-researchers-decision-makers approach remains the most robust solution for sound management and preservation of biological units.
The valorization of agro-industrial by-products is a sustainable approach to recovering high-value bioactive compounds. In this study, Opuntia ficus-indica (L.) Mill. seed press residues were investigated as a source of phenolic and flavonoid compounds using microwave-assisted extraction (MAE). A multi-step optimization strategy was implemented, combining preliminary single-factor experiments (OVAT), response surface methodology based on a Box-Behnken design (BBD), and machine learning modeling using K-nearest neighbors coupled with the dragonfly algorithm (KNN_DA), followed by desirability-based validation. The effects of ethanol concentration (50-100%), microwave power (400-800 W), extraction time (2-4 min), and liquid-to-solid ratio (30-50 mL/g) were evaluated on Folin-Ciocalteu reducing capacity (FCRC), AlCl3 complexation response, and antioxidant activity assessed by DPPH radical scavenging and reducing power assays. Optimal conditions were identified at 50% ethanol, 800 W microwave power, 4 min extraction time, and a liquid-to-solid ratio of 47.28 mL/g. Under these conditions, FCRC reached 376.85 ± 0.23 mg GAE/100 g DW and 49.16 ± 0.33 mg QE/100 g DW for AlCl3 complexation response, with prediction errors of 2.80% and 0.82%, respectively. The optimized extracts exhibited enhanced antioxidant activity. These findings confirm MAE as a rapid and environmentally friendly technique and highlight the predictive performance of the KNN_DA model for process optimization.
The diversity of Algerian Saharan wheat is still poorly known. A total of 962 samples, among which farmers identified 57 bread wheat and four durum wheats landraces as well as three mixtures between the two species, were collected in six oases of the Adrar location and four of the Tamanrasset location. Seeds were grown in the Adrar experimental station, and plants were characterized using 15 descriptors related to spike, glume and kernel morphology. Frequency distributions were evaluated and diversity indices (H′) calculated for each descriptor. Polymorphism of descriptors was higher in bread wheat, compared to durum wheat. The highest H′ values were noted for kernel shape, kernel color, awn color, global beak shape and spike density in bread wheat and for awnedness, beak tip shape, hair on spikelet basis and marginal pubescence of the rachis in durum wheat. The frequency distributions significantly varied among landraces for most descriptors. Some also varied within landraces, indicating intra-variability or homonymy. Differences in frequency of distribution were observed between locations and among oases within locations for all descriptors. High diversity indices were noted for most of them. The distribution of phenotypic traits along the Saharan environmental gradient revealed a local adaptation of genotypes to extreme environmental conditions. The study confirmed the peculiarity and high diversity of the Algerian oasis wheat genetic resources and highlighted the importance of preserving them and using them in breeding programs.
As part of the evaluation, preservation and development of plant genetic resources of food and fodder interest in Algeria, eight (08) local populations of the species Pisum sativum L. (Fabaceae) were collected from farmers, in an area of South-Western Algeria, mainly in Adrar. This part of the country is considered to be one of the hottest regions in the world (hyper-arid Saharan zone). Following this survey, a complete randomised block trial, with three (03) replications, was set up at the experimental station (INRAA / Adrar), for two consecutive agricultural campaigns (2018/2019; 2019/2020). Twenty-two (22) morphological, phenological and biometrical characteristics, relating to vegetative development, flowering, pods and seeds, were considered. Ecological factors (rainfall, temperature, altitude), characterizing the origin environments of populations were also taken into account. Analysis of variance revealed significant differences for most of the characteristics. Significant variation was recorded for phenological stages linked to vegetative development, flowering and pod formation, as well as for biometrical characteristics relating to production. Interaction analysis indicates a strong influence of the environment (Year) on most of the morpho-phenological traits of populations, whereas this influence would be lesser on biometrical characteristics. The correlation matrix revealed several significant links. In addition, the results indicated the existence of significant relationships between some phenological characteristics (emergence date and flowering duration) and a single ecological factor (altitude), characterizing the origin environment of the populations. Principal component analysis (PCA) permitted to constitute different groups of populations with similar characteristics. The evaluation of Pisum sativum populations can contribute to the diversification and development of legumes for human and animal consumption. This will enable the development of livestock farming and its products and consequently will improve the living standard of local populations in this desert region of the country.
