Crop genetic erosion: understanding and responding to loss of crop diversity.

Crop diversity underpins the productivity, resilience and adaptive capacity of agriculture. Loss of this diversity, termed crop genetic erosion, is therefore concerning. While alarms regarding evident declines in crop diversity have been raised for over a century, the magnitude, trajectory, drivers and significance of these losses remain insufficiently understood. We outline the various definitions, measurements, scales and sources of information on crop genetic erosion. We then provide a synthesis of evidence regarding changes in the diversity of traditional crop landraces on farms, modern crop cultivars in agriculture, crop wild relatives in their natural habitats and crop genetic resources held in conservation repositories. This evidence indicates that marked losses, but also maintenance and increases in diversity, have occurred in all these contexts, the extent depending on species, taxonomic and geographic scale, and region, as well as analytical approach. We discuss steps needed to further advance knowledge around the agricultural and societal significance, as well as conservation implications, of crop genetic erosion. Finally, we propose actions to mitigate, stem and reverse further losses of crop diversity.

Farm-Level Agricultural Biodiversity in the Peruvian Andes Is Associated with Greater Odds of Women Achieving a Minimally Diverse and Micronutrient Adequate Diet.

Background: The extent to and mechanisms by which agricultural biodiversity may influence diet diversity and quality among women are not well understood. Objectives: We aimed to 1) determine the association of farm-level agricultural biodiversity with diet diversity and quality among women of reproductive age in Peru and 2) determine the extent to which farm market orientation mediates or moderates this association. Methods: We surveyed 600 households with the use of stratified random sampling across 3 study landscapes in the Peruvian Andes with diverse agroecological and market conditions. Diet diversity and quality among women were assessed by using quantitative 24-h dietary recalls with repeat recalls among 100 randomly selected women. We calculated a 10-food group diet diversity score (DDS), the Minimum Dietary Diversity for Women (MDD-W) indicator, probability of adequacy (PA) of 9 micronutrients by using a measurement-error model approach, and mean PA (MPA; mean of PAs for all nutrients). Agricultural biodiversity was defined as a count of crop species cultivated by the household during the 2016-2017 agricultural season. Results: In regression analyses adjusting for sociodemographic and agricultural characteristics, farm-level agricultural biodiversity was associated with a higher DDS (incidence rate ratio from Poisson regression: 1.03; P < 0.05) and MPA (ordinary least-squares ß-coefficient: 0.65; P < 0.1) and higher odds of achieving a minimally diverse diet (MDD-W: OR from logistic regression: 1.17; 95% CI: 1.11, 1.23) and a diet that met a minimum threshold for micronutrient adequacy (MPA >60%: OR: 1.21; 95% CI: 1.10, 1.35). Farm market orientation did not consistently moderate these associations, and in path analyses we observed no consistent evidence of mediation of these associations by farm market orientation. Conclusions: Farm-level agricultural biodiversity was associated with moderately more diverse and more micronutrient-adequate diets among Peruvian women. This association was consistent across farms with varying levels of market orientation, although agricultural biodiversity likely contributed to diets principally through subsistence consumption.

Ex situ conservation priorities for the wild relatives of potato (solanum L. Section petota).

Crop wild relatives have a long history of use in potato breeding, particularly for pest and disease resistance, and are expected to be increasingly used in the search for tolerance to biotic and abiotic stresses. Their current and future use in crop improvement depends on their availability in ex situ germplasm collections. As these plants are impacted in the wild by habitat destruction and climate change, actions to ensure their conservation ex situ become ever more urgent. We analyzed the state of ex situ conservation of 73 of the closest wild relatives of potato (Solanum section Petota) with the aim of establishing priorities for further collecting to fill important gaps in germplasm collections. A total of 32 species (43.8%), were assigned high priority for further collecting due to severe gaps in their ex situ collections. Such gaps are most pronounced in the geographic center of diversity of the wild relatives in Peru. A total of 20 and 18 species were assessed as medium and low priority for further collecting, respectively, with only three species determined to be sufficiently represented currently. Priorities for further collecting include: (i) species completely lacking representation in germplasm collections; (ii) other high priority taxa, with geographic emphasis on the center of species diversity; (iii) medium priority species. Such collecting efforts combined with further emphasis on improving ex situ conservation technologies and methods, performing genotypic and phenotypic characterization of wild relative diversity, monitoring wild populations in situ, and making conserved wild relatives and their associated data accessible to the global research community, represent key steps in ensuring the long-term availability of the wild genetic resources of this important crop.

Effect of production environment, genotype and process on the mineral content of native bitter potato cultivars converted into white chuño.

BACKGROUND: Variables and interaction effects affecting the mineral concentration of Andean bitter potatoes converted into so-called white chuño are unknown. We report on the effect of three contrasting production environments (E) on the dry matter (DM), zinc, iron, calcium, potassium, magnesium, phosphorus and sodium concentration of four potato native bitter genotypes (G) processed (P) into two different 'types' of white chuño. RESULTS: The DM content and iron, calcium, magnesium and sodium concentration of white chuño are significantly dependent on E, G, P, and E × G × P interaction (predominantly at P < 0.01). In particular, the DM content and calcium concentration are influenced by all variables and possible interaction effects. The zinc and potassium concentration are not significantly dependent on E × G, G × P or E × G × P interaction effects, while the phosphorus concentration is not significantly affected by the G × P or E × G × P interaction effect. Zinc, phosphorus and magnesium concentrations decrease in the ranges of 48.3-81.5%, 61.2-73.0% and 62.0-89.7% respectively. The decrease in potassium is particularly severe, with 122- to 330-fold losses. Iron and calcium increase by 11.2-45.6% and 74.5-714.9% respectively. CONCLUSION: E, G, P, and various interaction effects influence the mineral concentration of traditionally processed tubers. We speculate that mineral losses are caused by leaching, while increases of iron and calcium are a likely result of absorption.