Yield stability in small red inter-racial common bean lines in Kenya

Agronomic performance of new common bean ( Phaseolus vulgaris L.) varieties may vary considerably in diverse agro-ecological zones, due to genotype-environment (G x E) interactions. A multi-site evaluation is, therefore, crucial in elite lines selection as it considers simultaneously both yield and stability of performance, making selection of genotypes more precise and refined. This study aimed at assessing the agronomic performance and yield stability of 24 F1.7 small red bean lines, selected for multiple disease resistance, using molecular markers from 16 inter-racial bean populations. The study lines were evaluated in low, medium and high altitude agro-ecological conditions in Kenya. G x E effects for grain yield were highly significant (P<0.001), implying that the agronomic potential of the small red bean lines varied with agro-ecological zones. Tigoni, the high altitude (2130 m above sea level) test site had the highest grain yield (3,809 kg ha-1). There were no significant differences between medium altitude (1820 masl) Kabete (1,100 kg ha-1) and low altitude (1150 masl) Mwea (1,025 kg ha-1) sites. Number of pods per plant was strongly positively correlated with seed yield (r=0.85***), and could be adopted by breeders as an indirect selection method for grain yield. The G x E interaction on grain yield was high (14.4%), implying that most of genotypes should be selected and recommended to specific environments. The high yielding line, KMA13-25-09 (3,385 kg ha-1), was the least stable across sites. Disease severity score for target diseases was low to intermediate regardless of the genotypes and sites.Les performances agronomiques des nouvelles vari\ue9t\ue9s de haricot commun ( Phaseolus vulgaris L.) peuvent varier consid\ue9rablement dans diverses zones agro-\ue9cologiques, en raison des interactions g\ue9notype-environnement (G x E). Une \ue9valuation multi-site est donc cruciale pour la s\ue9lection des lign\ue9es d\u2019\ue9lite, car elle prend en compte simultan\ue9ment le rendement et la stabilit\ue9 des performances, rendant la s\ue9lection des g\ue9notypes plus pr\ue9cise et affin\ue9e. Cette \ue9tude visait \ue0 \ue9valuer les performances agronomiques et la stabilit\ue9 au rendement de 24 lign\ue9es de haricots rouges F1.7, s\ue9lectionn\ue9es pour leur r\ue9sistance \ue0 de multiples maladies, \ue0 l\u2019aide de marqueurs mol\ue9culaires provenant de 16 populations de haricots interraciaux. Les lign\ue9es \ue9tudi\ue9es ont \ue9t\ue9 \ue9valu\ue9es dans des conditions agro-\ue9cologiques d\u2019altitude basse, moyenne et haute au Kenya. Les effets de G x E sur le rendement en grain \ue9taient tr\ue8s significatifs (P <0,001), ce qui impliquait que le potentiel agronomique des petites lign\ue9es de haricots rouges variait selon les zones agro-\ue9cologiques. Tigoni, le site d\u2019essai \ue0 haute altitude (2130 m au dessus du niveau de la mer), a eu le rendement grainier le plus \ue9lev\ue9 (3 809 kg ha-1). Il n\u2019y avait pas de diff\ue9rences significatives entre les sites de moyenne altitude (1820 m au dessus du niveau de la mer) de Kabete (1 100 kg ha-1) et de basse altitude (1150 m au dessus du niveau de la mer) Mwea (1 025 kg d\u2019ha-1). Le nombre de gousses par plante \ue9tait fortement corr\ue9l\ue9 positivement au rendement en graines (r = 0,85 ***) et pourrait \ueatre adopt\ue9 par les selectionneurs comme m\ue9thode de s\ue9lection indirecte pour le rendement en grains. L\u2019interaction G x E sur le rendement en grain \ue9tait \ue9lev\ue9e (14,4%), ce qui implique que la plupart des g\ue9notypes devraient \ueatre s\ue9lectionn\ue9s et recommand\ue9s pour des environnements sp\ue9cifiques. La lign\ue9e \ue0 haut rendement, KMA13-25-09 (3 385 kg ha-1), \ue9tait la moins stable sur tous les sites. Le score de gravit\ue9 de la maladie pour les maladies vis\ue9es \ue9tait faible \ue0 interm\ue9diaire, quels que soient les g\ue9notypes et les sites

Optimized protocol for in vitro pollen germination in yam (Dioscorea spp.)

Open Access Journal; Published online: 18 Apr 2021Yam (Dioscorea spp.) plants are mostly dioecious and sometimes monoecious. Low, irregular, and asynchronous flowering of the genotypes are critical problems in yam breeding. Selecting suitable pollen parents and preserving yam pollen for future use are potential means of controlling these constraints and optimizing hybridization practice in yam breeding programs. However, implementing such procedures requires a robust protocol for pollen collection and viability testing to monitor pollen quality in the field and in storage. This study, therefore, aimed at optimizing the pollen germination assessment protocol for yam. The standard medium composition was stepwisely modified, the optimal growth condition was tested, and in vivo predictions were made. This study showed that the differences in yam pollen germination percentage are primarily linked to the genotype and growing conditions (i.e., medium viscosity, incubation temperature, and time to use) rather than the medium composition. The inclusion of polyethylene glycol (PEG) in the culture medium caused 67–75% inhibition of germination in D. alata. Although the in vivo fertilization was dependent on female parents, the in vitro germination test predicted the percentage fruit set at 25.2–79.7% and 26.4–59.7% accuracy for D. rotundata and D. alata genotypes, respectively. This study provides a reliable in vitro yam pollen germination protocol to support pollen management and preservation efforts in yam breeding

Benefits and drivers of farm mechanisation in Ruzizi Plain, Eastern Democratic Republic of Congo

Farm mechanisation plays a major role in the agricultural sector, as it facilitates achievement of energy-intensive operations. In developing countries, policies and technical constraints have greatly affected the development of a coherent agricultural mechanisation system, that is accessible to farmers, especially the poorest. This study aimed to identify the socioeconomic factors that have driven the use of different sources of farm power in family farming in Ruzizi Plain in Democratic Republic of Congo. A random sample of 190 smallholder farmers and 30 technicians were surveyed in 2014 and 2015 in six areas of Kamanyola, Luvungi, Luberizi, Sange, Kiringye and Kiliba. Results showed that mechanisation in the Ruzizi Plain involved a range of sources of farm power, including draft animals, tractors and rototillers. Factors such as gender, attitude of the head of a household, farm productivity and profitability and non-farm incomes played a crucial role in the choice of whether or not to mechanise. Maize profitability was higher under mechanisation (US$535.46 ha-1) compared to non-user farms (US$ 7.73 ha-1). For cassava, however, there were no significant differences in profitability between mechanised and non-mechanised farms. Other benefits of mechanisation included better working conditions, reduction in the duration of farming operations, and the expansion of cultivated land parcels.La m\ue9canisation agricole joue un r\uf4le majeur dans le secteur agricole, car elle facilite l\u2018aboutissement d\u2018op\ue9rations \ue0 forte intensit\ue9 \ue9nerg\ue9tique. Dans \ua0les pays sous-d\ue9velopp\ue9s, les politiques et les contraintes techniques ont fortement affect\ue9 le d\ue9veloppement d\u2019un syst\ue8me de m\ue9canisation agricole coh\ue9rent, accessible aux agriculteurs, en particulier aux plus pauvres. Cette \ue9tude visait \ue0 identifier les facteurs socio\ue9conomiques qui ont conduit \ue0 l\u2019utilisation de diff\ue9rentes sources d\u2019\ue9nergie agricole dans l\u2019agriculture familiale dans la plaine de Ruzizi en R\ue9publique d\ue9mocratique du Congo. Un \ue9chantillon al\ue9atoire de 190 petits exploitants et 30 techniciens a \ue9t\ue9 interrog\ue9 en 2014 et 2015 dans six zones de Kamanyola, Luvungi, Luberizi, Sange, Kiringye et Kiliba. Les r\ue9sultats ont montr\ue9 que la m\ue9canisation dans la plaine de Ruzizi impliquait une gamme de sources d\u2019\ue9nergie agricole, y compris les animaux de trait, les tracteurs et les motoculteurs. Des facteurs tels que le sexe, l\u2019attitude du chef de m\ue9nage, la productivit\ue9 et la rentabilit\ue9 agricoles et les revenus non agricoles ont jou\ue9 un r\uf4le crucial dans le choix de m\ue9caniser ou non. La rentabilit\ue9 du ma\uefs \ue9tait plus \ue9lev\ue9e sous m\ue9canisation (US$535.46 ha-1) par rapport aux exploitations non utilisatrices (US$ 7.73 ha-1). Pour le manioc, cependant, il n\u2019y avait pas de diff\ue9rences significatives de rentabilit\ue9 entre les exploitations m\ue9canis\ue9es et non m\ue9canis\ue9es. Les autres avantages de la m\ue9canisation comprenaient de meilleures conditions de travail, la r\ue9duction de la dur\ue9e des op\ue9rations agricoles et l\u2019expansion des parcelles de terres cultiv\ue9es

Water use efficiency of maize (Zea mays L.) crop under selected soil and water conservation practices along the slope gradient in Ruzizi watershed, eastern D.R. Congo

Open Access Journal; Published online: 18 Oct 2022Maize (Zea mays L.) productivity is constrained by water shortages in the predominantly rainfed agriculture of the tropical semi-arid Ruzizi Plain, in the eastern Democratic Republic of Congo (DRC). The region is characterized by a high seasonal and inter-annual rainfall variability and a frequent occurrence of consecutive dry days within growing seasons. Consequently, planning water utilization in rainfed agriculture has become complex, as appropriate soil water conservation (SWC) practices are lacking among most smallholder farmers. Identifying practices that increase water use efficiency (WUE) along the slope gradient is crucial for supporting maize production in the region. In this study, we assessed, for three growing seasons, the effectiveness of two SWC practices (tied ridges and Zai pits) in improving the WUE of two maize varieties along three slope gradients (0–2, 2–8, and 8–15%) in the tropical semi-arid Ruzizi Plain. In this area, rainfall amounts (142–289 mm) were consistently below the evapotranspiration demands (356–533 mm) across the three growing seasons. Tied ridges recorded the highest grain yield (2.16 t ha−1) and WUE (15.23 kg mm−1), especially at low slopes, when compared to Zai pits and conventional tillage. For all SWC practices, WUE decreased with the slope gradient (p < 0.01). Furthermore, a decrease in stored soil water (SWS) at silking and maturity stages (milk, dough, and dent stages) negatively affected the WUE. The variety had no significant effect on grain yield and WUE. Root biomass (RBM), shoot biomass (SBM), and leaf area index (LAI) at the flowering stage were the most associated with the WUE (R2 = 58.5%). In conclusion, tied ridges showed potential for improving maize WUE and yield in the water-deficient conditions that characterize the Ruzizi Plain, and could be promoted to improve the maize productivity among smallholder farmers

Experimentally validated reconstruction and analysis of a genome-scale metabolic model of an anaerobic Neocallimastigomycota fungus

Anaerobic gut fungi in the phylum Neocallimastigomycota typically inhabit the digestive tracts of large mammalian herbivores, where they play an integral role in the decomposition of raw lignocellulose into its constitutive sugar monomers. However, quantitative tools to study their physiology are lacking, partially due to their complex and unresolved metabolism that includes the largely uncharacterized fungal hydrogenosome. Modern omics approaches combined with metabolic modeling can be used to establish an understanding of gut fungal metabolism and develop targeted engineering strategies to harness their degradation capabilities for lignocellulosic bioprocessing. Here, we introduce a high-quality genome of the anaerobic fungus Neocallimastix lanati from which we constructed the first genome-scale metabolic model of an anaerobic fungus. Relative to its size (200 Mbp, sequenced at 62× depth), it is the least fragmented publicly available gut fungal genome to date. Of the 1,788 lignocellulolytic enzymes annotated in the genome, 585 are associated with the fungal cellulosome, underscoring the powerful lignocellulolytic potential of N. lanati. The genome-scale metabolic model captures the primary metabolism of N. lanati and accurately predicts experimentally validated substrate utilization requirements. Additionally, metabolic flux predictions are verified by 13C metabolic flux analysis, demonstrating that the model faithfully describes the underlying fungal metabolism. Furthermore, the model clarifies key aspects of the hydrogenosomal metabolism and can be used as a platform to quantitatively study these biotechnologically important yet poorly understood early-branching fungi

A comparative genomics study of 23 Aspergillus species from section Flavi

Section Flavi encompasses both harmful and beneficial Aspergillus species, such as Aspergillus oryzae, used in food fermentation and enzyme production, and Aspergillus flavus, food spoiler and mycotoxin producer. Here, we sequence 19 genomes spanning section Flavi and compare 31 fungal genomes including 23 Flavi species. We reassess their phylogenetic relationships and show that the closest relative of A. oryzae is not A. flavus, but A. minisclerotigenes or A. aflatoxiformans and identify high genome diversity, especially in sub-telomeric regions. We predict abundant CAZymes (598 per species) and prolific secondary metabolite gene clusters (73 per species) in section Flavi. However, the observed phenotypes (growth characteristics, polysaccharide degradation) do not necessarily correlate with inferences made from the predicted CAZyme content. Our work, including genomic analyses, phenotypic assays, and identification of secondary metabolites, highlights the genetic and metabolic diversity within section Flavi.Peer reviewe

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol—which is a marker of cardiovascular risk—changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million–4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.</p

A century of trends in adult human height

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5-22.7) and 16.5 cm (13.3-19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8-144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries