Breeding Stage Research Articles

Construction and Analysis of miRNA–mRNA Interaction Network in Ovarian Tissue of Wanxi White Geese Across Different Breeding Stages

Ovarian development significantly influences the laying performance of geese. In this study, the transcriptome analysis was conducted on the ovarian tissues of Wanxi White Geese during the pre-laying (KL), laying (CL), and ceased-laying period (XL). Short Time-series Expression Miner (STEM) analysis and miRNA–mRNA regulatory network construction were performed to identify the key genes and miRNAs regulating laying traits. Comparative analysis of KL vs. CL, CL vs. XL, and XL vs. KL groups resulted in the identification of 337, 136, and 525 differentially expressed genes (DEGs), and 258, 1131, and 909 differentially expressed miRNAs (DEMs), respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis (p < 0.05) revealed that the main enrichment pathways of DEGs and DEMs at different breeding periods were Neuroactive ligand–receptor interaction, GnRH signaling pathway and Wnt signaling pathway, all associated with ovarian development. According to the three groups of common pathways, four DEGs were screened out, including INHBB, BMP5, PRL, and CGA, along with five DEMs, including let-7-x, miR-124-y, miR-1-y, and miR-10926-z, all of them may affect ovarian development. A miRNA–mRNA regulatory network was constructed through integrated analysis of DEGs and DEMs, revealing nine miRNAs highly associated with ovarian development: miR-101-y, let-7-x, miR-1-x, miR-17-y, miR-103-z, miR-204-x, miR-101-x, miR-301-y, and miR-151-x. The dual-luciferase reporter gene verified the target relationship between WIF1 and miR-204-x, suggesting that these miRNAs may influence ovarian development in Wanxi White Goose by regulating the expression levels of their target genes within ovarian tissue. This study provides a theoretical foundation for analyzing the mechanisms of ovarian development across different breeding periods and accelerating the cultivation of new breeds through post-transcriptional regulation levels.

Breeding stages affect egg recognition in azure-winged magpies (Cyanopica cyanus)

Egg rejection often involves a cognitive process of recognizing foreign eggs, which can vary not only between species or among different individuals of the same species, but also within the same individual during different breeding stages, leading to markedly different responses to parasitic eggs. We conducted a comparative study in Wuhan, Hubei, and Fusong, Jilin, China, on the recognition and rejection behavior of azure-winged magpies (Cyanopica cyanus) at different breeding stages (pre-egg-laying, one-host-egg, multi-host-egg and early incubation stages). In the Fusong population, there was a significant difference in the rejection rate of model eggs by azure-winged magpies at different stages of the egg-laying period. During the one-host-egg stage, the rejection rate (63.6%) was significantly lower than that during the pre-egg-laying stage (85.7%) and the multi-host-egg stage (100%). The population of azure-winged magpies in Wuhan exhibited a 100% rejection rate towards model eggs during the pre-egg-laying stage. Furthermore, during the incubation stage, azure-winged magpies were able to accurately recognize and reject foreign eggs even when those were in majority. This indicates that azure-winged magpies employ a template-based recognition mechanism rather than relying on discordance mechanism for recognition after the onset of incubation. This study suggests that while azure-winged magpies can truly recognize their own eggs, different breeding stages still influence their rejection response towards parasitic eggs, especially during the pre-egg-laying and egg laying stages.

Prevalence and local transmission of haemosporidian (Haemosporida) parasites in nestlings of birds of prey (Aves, Accipitriformes) in the temperate forests in Lithuania

Wild birds of prey (Accipitriformes) are infected with haemosporidian (Haemosporida) parasites worldwide, and it is known that these parasites can negatively affect their health. These birds are less studied due to their low densities in ecosystems, conservation status, and difficulty of accessing them in the wild. Therefore, in this study, we focused on nestlings of birds of prey that are accessible in their nests during late breeding stages in temperate forests in Lithuania. Investigating haemosporidian parasites in nestlings is crucial for understanding local parasite transmission. To identify the haemosporidian parasite species transmitted in Lithuania, we sampled nestlings of the white-tailed eagles (Haliaeetus albicilla), lesser spotted eagles (Clanga pomarina), and common buzzards (Buteo buteo) in 2019–2022. Blood samples were collected from the nestlings, and molecular methods were employed to sequence a fragment of the parasite's cytochrome b (cyt b) gene using specific primers (Plas1F/HaemNR3 and 3760F/HaemJR4). In addition to molecular techniques, microscopy was used to examine blood smears for the presence of parasites. Our results revealed that nestlings of birds of prey were infected only with Leucocytozoon spp., with an overall prevalence of 30.5%. The prevalence was similar between years, but it was significantly species-dependent. The common buzzard nestlings had the highest prevalence (80%), followed by the lesser spotted eagle (29.2%) and the white-tailed eagle (13.2%). A total of nine genetic lineages were identified, with five of them being novel. Our study demonstrates that Leucocytozoon parasites are actively transmitted to nestlings of birds of prey in Lithuania, with a high prevalence.

Comparison of nutritional value of the wild and cultivated spiny loaches at three growth stages.

Environmental pollution and overfishing of wild spiny loach have led to the increased demand for breeding the fish. However, the nutritional value between the wild and cultivated spiny loaches was unknown. Therefore, this study aimed to evaluate the nutritional components among the wild and cultivated spiny loaches at different growth stages by analyzing and comparing the proximate compositions, fatty acids, amino acids and volatile compounds. Results showed that the cultivated ones had significantly higher energy and fat contents than the wild. Particularly, the cultivated second-age spiny loach contained the highest contents of polyunsaturated fatty acids (4.83 ± 0.01%) and EPA + DHA (0.85 ± 0.02%). Besides, the total essential amino acid content of cultivated second-age spiny loach was 2201.28, exceeding that recommended in the FAO/WTO scoring pattern (2,190). And it had the highest flavor amino acid (6.24 ± 0.04 g/100 g), essential amino acid index value (71.82) and higher contents of volatile compounds. Overall, the cultivated spiny loach, especially that at the second growth stage, displayed the highest nutritional value. The findings of this study would help farmers to harvest the suitable breeding stage of spiny loaches from the perspective of nutritional value, which is beneficial to the sustainable fish farming.

Assessing genotype-by-environment interactions for maydis leaf blight disease in maize (Zea mays L.) germplasm and identification of stable donors for breeding resistant hybrid varieties

Abstract This study investigates the impact of environmental factors and genotype-by-environment interactions (GEI) on the expression of maydis leaf blight (MLB) resistance in a diverse maize germplasm comprising 359 genotypes. Extensive field trials were conducted, involving artificial inoculations and disease scoring across two locations over two years. Using genotype and genotype–environment (GGE) biplot analysis based on the site regression model (SREG), we identified stable MLB-resistant 10 donors with consistent genotypic responses. These inbred lines, which consistently exhibited disease scores of ⩽3 across locations, are recommended as potential parents for breeding MLB-resistant varieties. Furthermore, the identification of a non-crossover interaction and high correlations among testing locations allowed us to define a single mega-environment for the initial screening of MLB resistance in a large set of maize germplasm. This study suggests that initial screenings can be efficiently conducted in one representative location, with validation of resistant lines at multiple sites during advanced breeding stages. This approach optimizes the use of land, labour and resources in MLB resistance testing.

Transmission of carbapenem-resistant enterobacterales producing NDM-5 during the broiler breeding process in China

This study conducted a four-month monitoring of carbapenem resistance in a broiler breeding farm in China. A total of 185 carbapenem-resistant bacterial isolates were obtained from 2298 cloacal swabs from broiler breeders and their offspring within a production cycle. The detection rate of carbapenem-resistant isolates was higher during the brooding period. Whole-genome sequencing (WGS) was performed on 133 isolates based on sampling stages, including 113 carbapenem-resistant Enterobacterales (CRE) isolates and 20 Stenotrophomonas pavanii isolates, which have intrinsic resistance to carbapenems. A total of 69 antibiotic resistance genes (ARGs), including blaNDM-1, mcr-1, and blaNDM-5, were identified among the sequenced CRE isolates. Notably, blaNDM-5 (92.0 %, 104/113) was the primary contributor to carbapenem resistance. CRE isolates from the same breeding stage exhibited close genomic relationships, and the blaNDM-5 genes were observed in similar genetic backgrounds, indicating the transmission of CRE strains and blaNDM-5 during the broiler breeding process. No CRE was isolated from 0 d broiler offspring, suggesting that broiler breeders were not the direct source of CRE in their offspring. Tracing the feeding process revealed that brooder and rearing houses were likely key factors in the cross-transmission of CRE between broiler breeders and their offspring. CRE pose a significant threat to public health and food safety. China is one of the world's leading poultry producing and consuming countries. This study provided insights into the epidemiological trends and key transmission nodes of carbapenem resistance and CRE within the broiler breeding process, which could help the control of antibiotic resistance and bacterial infections in the broiler industry.

Comparative characteristics of the development of germ cells in Siberian sturgeon and sterlet in the second year of cultivation, obtained using cryopreserved and native sperm in industrial farms

For the first time, the effect of cryopreservation in comparison with native sperm from domesticated forms of Siberian sturgeon and sterlet on the development of germ cells and the body as a whole in the offspring obtained in the second year of cultivation, taken during fertilization of eggs of Siberian sturgeon and sterlet in the conditions of the Konakovsky department of the Branch for the freshwater fisheries of the VNIRO (VNIIPRKH). The correlation of body weight with the mass of the left, right and gonad length is shown, the greater the body weight, the greater the mass and length of the gonads. In the early stages of the body’s development, body weight and the appearance of gonads correlate due to the presence of parenchymal and adipose tissue in the gonads, blood cells — histiocytes (a type of macrophages), which resorb cells unnecessary to the body, are clearly visible in the gonads. In females and males of Siberian sturgeon and sterlet, regardless of body weight, there is a consistent manifestation of the patterns of gametogenesis. In the experimental and control groups, the development of germ cells is similar, and anatomical differentiation of sex takes place. The Siberian sturgeon has the I stage of gonad maturity, the sterlet has the I, the beginning of the II stage of gonad maturity, they are species–specific and regular. No violations were noted, the appearance of hermaphrodite in sturgeons is a known fact and is not a violation, because the process of germ cell development in the “female” and “male” gonads is proceeding in a timely manner. The good quality of spermatozoa in domesticated forms of Siberian sturgeon and sterlet, which have passed several stages of breeding and are located in the Konakovsky department, is also important.

In Vivo Leaf Inoculation: An Alternative Method to Assess the Disease Resistance of Hybrid Clones in Poplar Breeding of Stem Canker Disease.

Stem canker diseases caused by the pathogen Cytospora chrysosperma (Pers.) Fr.) and Botryosphaeria dothidea (Moug. ex Fr.) Ces. & de Not. are the two major forest diseases in the poplar plantations in China, sometimes which can destroy all the poplar seedlings or severely damage mature poplar forests. Hybrid breeding is the most direct and efficient method of controlling and managing tree diseases. However, assessing disease resistance or selecting disease-resistance clones based on In vitro stem inoculation is inefficient, time-consuming, and expensive, limiting the development of hybrid breeding of poplar stem canker disease. In this study, we proposed an alternative method to assess disease resistance to stem canker pathogens through in vivo leaf inoculation. The test materials used in this method can be on 1-year-old poplar saplings or the annual branches of perennial poplars in the greenhouse or the field. The critical step of this alternative method is the selection of inoculating leaves: the 5-7th newly matured leaves might be the most suitable. The second critical step of the leaf inoculation method is to make wounds on plant leaves through needle pierces, providing sufficient lesions to measure disease severity. For the adequate number of leaves produced in the early stage of poplar breeding, this in vivo leaf inoculation contributes to the rapid, accurate, and large-scale screening of the disease-resistance poplar clones to stem canker pathogens. Moreover, this leaf inoculation method will also serve as an efficient method for screening pathotypes of stem canker disease pathogen C. chrysosperma, B.dothidea, or other poplar stem canker pathogens.

Integrated Morphological, Comparative Transcriptomic, and Metabolomic Analyses Reveal Mechanisms Underlying Seasonal Patterns of Variation in Spines of the Giant Spiny Frog (Quasipaa spinosa).

Quasipaa spinosa, commonly known as the spiny frog, is an economically valued amphibian in China prized for its tender meat and nutritional value. This species exhibits marked sexual dimorphism, most notably the prominent spiny structures on males that are pivotal for mating success and species identification. The spines of Q. spinosa exhibit strong seasonal variation, changing significantly with the reproductive cycle, which typically spans from April to October. Sexually mature males develop densely packed, irregularly arranged round papillae with black spines on their chests during the breeding season, which may then reduce or disappear afterward, while females have smooth chest skin. Despite their ecological importance, the developmental mechanisms and biological functions of these spines have been inadequately explored. This study integrates morphological, transcriptomic, and metabolomic analyses to elucidate the mechanisms underlying the seasonal variation in spine characteristics of Q. spinosa. Our results demonstrate that spine density inversely correlates with body size and that spine development is accompanied by significant changes in epidermal thickness and keratinization during the breeding season. Comparative transcriptomic analysis across different breeding stages revealed significant gene expression alterations in pathways related to extracellular matrix interactions, tyrosine metabolism, Wnt signaling, and melanogenesis. Metabolomic analysis further identified significant seasonal shifts in metabolites essential for energy metabolism and melanin synthesis, including notable increases in citric acid and β-alanine. These molecular changes are consistent with the observed morphological adaptations, suggesting a complex regulatory mechanism supporting spine development and functionality. This study provides novel insights into the molecular basis of spine morphogenesis and its seasonal dynamics in Q. spinosa, contributing valuable information for the species' conservation and aquaculture.

Productive response of the Japanese quail (Coturnix coturnix japonica) to different natural growth promoters in the breeding and development stage

Productive response of the Japanese quail (Coturnix coturnix japonica) to different natural growth promoters in the breeding and development stage

Year-round natural spawning, early ontogeny, and larval rearing of the painted sweetlips, Diagramma pictum (Thunberg, 1792) in a hatchery: Potential as a new species for mariculture

The painted sweetlips, Diagramma pictum, is an important species for commercial fisheries, game fishing, and the marine aquarium trade. However, limited knowledge is available about the captive breeding and early developmental stages of this species. This study presents the first report on natural spawning, early ontogeny, and appropriate rearing conditions (temperature, salinity, and initial prey) for larviculture of D. pictum. Natural spawning of D. pictum in captivity was observed year-round for two years, from 1 June 2019 to 31 July 2021. During this 792-day period, females produced 127 spawns, with 77.2% ± 27.2% resulting in fertilized eggs. The median fecundity per spawn was 841 eggs with an interquartile range of 1173 eggs, and the average hatch rate was 59.3 ± 22.0%. Fertilized eggs were spherical, buoyant, and had a diameter of 0.78 ± 0.02 mm. Embryonic development lasted 14 h and 30 min at 28.0 °C. Newly hatched larvae measured 1.81 ± 0.20 mm in total length (LT), with 26 myomeres and an oil globule in the ventroanterior area of the yolk sac. Additionally, the ultrastructural observations of the micropyle, accessory openings, neuromast, and head spines of eggs and early larvae were reported for the first time. At 3 days post-hatch (dph), the larvae measured 2.59 ± 0.16 mm LT at full yolk sac and oil globule resorption. First feeding was noted at this stage, as evidenced by the expansion of the digestive tract filled with live feed. The juvenile stage was reached by 25 dph, and juveniles had an average length of 32.54 ± 2.17 mm LT. Based on hatch and survival activity indices (SAI), we propose optimal water quality parameters for D. pictum larval rearing as a temperature of 26–28 °C and a salinity of 32–33 psu. In the first feeding experiment, survival rates were not significantly different between feeding treatments R (Brachionus rotundiformis; 5 rotifers mL−1) and R + C (B. rotundiformis; 4 rotifers mL−1 + Calanopia elliptica; 1 nauplii mL−1), but both were higher compared to treatment C (C. elliptica; 2 nauplii mL−1) at 9 dph. Our study emphasizes the importance of simultaneous consumption of rotifers and copepods as vital initial prey for the first feeding larvae of D. pictum. Additionally, this co-feeding may enhance larval development through an additive effect. These results demonstrate the potential for establishing captive breeding programs for this species.

Comparable foraging effort and habitat use between two geographically proximate tropical seabird colonies

Effective seabird conservation requires understanding their marine spatial ecology. Tracking can reveal details of their foraging ecology and habitat use, as well as the suitability of marine protected areas for at-sea conservation, but results are often regionally specific. Here we characterised the foraging behaviour of tropical breeding brown boobies Sula leucogaster in the Chagos Archipelago, Western Indian Ocean, and tested habitat requirements. GPS tracking of thirteen individuals from two colonies, located 142 km apart on the same atoll (Great Chagos Bank), showed similar foraging effort and habitat preferences despite differences in season and breeding stage. Brown boobies from both tracked populations foraged close to the colony along the atoll shelf edge, avoiding deep oceanic areas and shallow waters of the Great Chagos Bank atoll, but within the Chagos Archipelago Marine Protected Area. Sea-level height anomaly and sea surface temperature were important foraging predictors at both sites, although birds experienced distinct environmental conditions between colonies. These results suggest that while brown boobies have colony-specific at-sea foraging areas, similarities in habitat drivers of distribution and foraging behaviour can inform predictions of distributions at other colonies within the archipelago, with important benefits for at-sea conservation efforts.

Trophic plasticity of a tropical seabird revealed through DNA metabarcoding and stable isotope analyses

DNA metabarcoding and stable isotope analysis have significantly advanced our understanding of marine trophic ecology, aiding systematic research on foraging habits and species conservation. In this study, we employed these methods to analyse faecal and blood samples, respectively, to compare the trophic ecology of two Red-billed Tropicbird (Phaethonaethereus; Linnaeus, 1758) colonies on Mexican islands in the Pacific. Trophic patterns among different breeding stages were also examined at both colonies. Dietary analysis reveals a preference for epipelagic fish, cephalopods, and small crustaceans, with variations between colonies and breeding stages. Isotopic values (δ15N and δ13C) align with DNA metabarcoding results, with wider niches during incubation stages. Differences in diet are linked to environmental conditions and trophic plasticity among breeding stages, influenced by changing physiological requirements and prey availability. Variations in dietary profiles reflect contrasting environmental conditions affecting local prey availability.

Variation among cassava (Manihot esculenta Crantz) genotypes for storage root yield, yield components and response to cassava mosaic disease at the advanced breeding stage

Variation among cassava (Manihot esculenta Crantz) genotypes for storage root yield, yield components and response to cassava mosaic disease at the advanced breeding stage

Phenotypic characteristics of the mycelium of Pleurotus geesteranus using image recognition technology.

Phenotypic analysis has significant potential for aiding breeding efforts. However, there is a notable lack of studies utilizing phenotypic analysis in the field of edible fungi. Pleurotus geesteranus is a lucrative edible fungus with significant market demand and substantial industrial output, and early-stage phenotypic analysis of Pleurotus geesteranus is imperative during its breeding process. This study utilizes image recognition technology to investigate the phenotypic features of the mycelium of P. geesteranus. We aim to establish the relations between these phenotypic characteristics and mycelial quality. Four groups of mycelia, namely, the non-degraded and degraded mycelium and the 5th and 14th subcultures, are used as image sources. Two categories of phenotypic metrics, outline and texture, are quantitatively calculated and analyzed. In the outline features of the mycelium, five indexes, namely, mycelial perimeter, radius, area, growth rate, and change speed, are proposed to demonstrate mycelial growth. In the texture features of the mycelium, five indexes, namely, mycelial coverage, roundness, groove depth, density, and density change, are studied to analyze the phenotypic characteristics of the mycelium. Moreover, we also compared the cellulase and laccase activities of the mycelium and found that cellulase level was consistent with the phenotypic indices of the mycelium, which further verified the accuracy of digital image processing technology in analyzing the phenotypic characteristics of the mycelium. The results indicate that there are significant differences in these 10 phenotypic characteristic indices ( ), elucidating a close relationship between phenotypic characteristics and mycelial quality. This conclusion facilitates rapid and accurate strain selection in the early breeding stage of P. geesteranus.

Individual quality overwrites carry-over effects across the annual cycle of a long-distance migrant.

In seasonal environments, the fitness of animals depends upon the successful integration of life-history stages throughout their annual cycle. Failing to do so can lead to negative carry-over effects where individuals are transitioning into the next season in different states, consequently affecting their future performance. However, carry-over effects can be masked by individual quality when individuals vary in their efficiency at acquiring resources year after year (i.e. 'quality'), leading to cross-seasonal consistency in individual performance. Here we investigated the relative importance of carry-over effects and individual quality in determining cross-seasonal interactions and consequences for breeding success over the full annual cycle of a migratory seabird (black-legged kittiwake Rissa tridactyla). We monitored the reproduction and annual movement of kittiwakes over 13 years using geolocators to estimate their breeding success, distribution and winter energy expenditure. We combined this with an experimental approach (clutch removal experiment, 2 years) to manipulate the reproductive effort irrespective of individual quality. Piecewise path analyses showed that successful breeders reproduced earlier and were more likely to breed successfully again the following year. This positive interaction among consecutive breeding stages disappeared after controlling for individual quality, suggesting that quality was dominant in determining seasonal interactions. Moreover, controlling experimentally for individual quality revealed underlying carry-over effects that were otherwise masked by quality, with breeding costs paid in higher energy expenditure and delayed onset of reproduction. We highlight the need to combine an experimental approach along with long-term data while assessing apparent carry-over effects in wild animals, and their potential impact on fitness and population demography.

Pyramiding effects of favorable haplotypes of loci on major fiber yield and quality traits in Upland Cotton (Gossypium hirsutum L.)

Enhancing both fiber yield and quality is crucial in cotton breeding programs. Typically, a negative correlation exists between fiber yield and quality, and the strategy to decouple this relationship remains obscure. In this study, we generated three multi-parent intercross populations, encompassing 2,852 F2:3 lines, which represent fiber yield potential (FY), fiber quality potential (FQ), and a combination of both potentials (FYQ), derived from sixteen diverse Upland cotton cultivars. We utilized twenty-four kompetitive allele specific PCR (KASP) molecular markers, based on previously identified loci associated with fiber quality (FL5/FS1, FL3/FS2, and FL2) and fiber yield (BW1, BW2, and LP1), for genotyping purposes. The pyramiding of favorable haplotypes from three fiber quality-associated loci resulted in an increase exceeding 10% in fiber length (FL5+FL3+FL2+LP1) and in an increase exceeding 17% in fiber strength (FL5+FL3+FL2). Notably, our findings suggest that the combination of FL3+FL2+BW1+LP1 alleles has the potential to disrupt the negative correlation between fiber yield and quality. Lines harboring these alleles simultaneously exhibited an elevated lint percentage (LP), as well as enhanced fiber length and quality. This study offers robust molecular markers for the efficient selection of superior progeny with desired phenotypes in the early stages of cotton breeding. Furthermore, the allelic combination that concurrently improves fiber quality and yield sheds light on for further exploration the molecular basis of breaking unfavorable linkages in crop breeding.

DEVELOPING MULTILINE COWPEA VARIETIES ADAPTED TO LOCAL CROPPING SYSTEMS AND SPECIFIC FARMERS’ PRODUCTION GOALS THROUGH PARTICIPATORY BREEDING

<p><strong>Background</strong><strong>.</strong> Decentralized participatory breeding approach facilitate the development of varieties better suited for a diversity of farmers' contexts. To enhance breeding efficiency, formal methodological settings are needed to include, at early stage of selection, particular local practices and farmers’ preferences. <strong>Objective</strong><strong>.</strong> Evaluate how location, farmers’ profile and local cropping system could be taken into account to optimize selection of cowpea varieties in a decentralized context. <strong>Methodology:</strong> Twenty-two candidate multiline varieties of cowpea (<em>Vigna unguiculata L. </em>Walp) were developed from a biparental family of recombinant inbred lines. These varieties were subjected to selection under edaphic and climatic conditions of three locations and two cropping systems (intercropping <em>versus</em> sole cropping). Trials were carried out in collaboration with farmers' federations. Participatory evaluations were conducted over two years by the three groups of farmers defined by the following production goals: grains production as priority (“Grain priority profile”), fodder as priority (“Fodder priority profile”) and grain quality as priority (“Food processing priority profile”). <strong>Results</strong><strong>.</strong> The statistical analysis supported significant effects of location and cropping system on the agronomic traits, with interactions effects involving the variety. A strong correlation was observed between the varietal choices of the two farmers’ profiles which prioritized respectively grain and food processing. These farmers preferred varieties with higher grain yield and best grain quality. Farmers who prioritized fodder preferred more specific varieties, characterized by highest haulm yield. <strong>Implications.</strong> The clustering of farmers into specific profiles is an efficient method which allow expressing their diversified production goals through participatory evaluation. This led to more specific varietal choices for each of the profiles. <strong>Conclusion</strong><strong>.</strong> This study set cropping systems and farmer profiles as formal design factors at early breeding stage. These factors acted efficiently to support the process of varietal choice. The participatory approach highlighted the congruence and complementary between farmers’ and researchers’ knowledges. It helped identifying, for intercropping and sole cropping systems respectively, the most suitable varieties preferred by each of three respective farmers’ group.</p>

Scope and adaptive value of modulating aggression over breeding stages in a competitive female bird

Abstract In seasonally breeding animals, the costs and benefits of territorial aggression should vary over time; however, little work thus far has directly examined the scope and adaptive value of individual-level plasticity in aggression across breeding stages. We explore these issues using the tree swallow (Tachycineta bicolor), a single-brooded bird species in which females compete for limited nesting sites. We measured aggressiveness in nearly 100 females within 3 different stages: (1) shortly after territory-establishment, (2) during incubation, and (3) while caring for young chicks. Based on the timing, direction, and magnitude of behavioral changes between stages, we used k-means clustering to categorize each female’s behavior into a “plasticity type.” We then tested whether plasticity type and stage-specific aggression varied with key performance metrics. About 40% of females decreased aggressiveness across consecutive breeding stages to some degree, consistent with population-level patterns. 33% of females exhibited comparatively little plasticity, with moderate to low levels of aggression in all stages. Finally, 27% of females displayed steep decreases and then increases in aggression between stages; females exhibiting this pattern had significantly lower body mass while parenting, they tended to hatch fewer eggs, and they had the lowest observed overwinter survival rates. Other patterns of among-stage changes in aggressiveness were not associated with performance. These results reveal substantial among-individual variation in behavioral plasticity, which may reflect diverse solutions to trade-offs between current reproduction and future survival.

Development of portfolio management tools in crop breeding programs: a case study of cassava in sub-Saharan Africa

The response to the diverse needs along the cassava value chain, the urge to increase genetic gain, and the need for rapid varietal turnover will necessitate not only technological innovations but also transformation of public breeding programs in sub-Saharan Africa (SSA). We developed guiding, flexible and adaptative tools for portfolio management of cassava breeding. The cassava breeding and product development pipeline process was mapped to illustrate activities of each stage, as well as to clarify key decision points. Stakeholders involved at all stages of breeding were identified. This allowed for identification of gaps and new crucial functions. To clarify accountability and reduce complexity in the decision-making at key decision points, the roles were mapped against decision-rights at each stage-gate. Cassava crop calendars for the different regions in SSA were developed to facilitate better planning. A product advancement template was developed to guide product advancement. The tools that have been developed and stage-gate mapping, will support regional efforts to establish more structured, transparent, participatory, efficient, inclusive, and demand-driven cassava breeding in the region. These approaches could be customized to other commodities.