RESISTANCE TO POST-HARVEST MICROBIAL ROT IN YAM: INTEGRATION OF GENOTYPE AND STORAGE METHODS

Post-harvest microbial rot is an important disease that causes severe losses in yam ( Dioscorea spp.) storage. Rot from microbial infection of healthy yam tubers reduces their table quality and renders them unappealing to consumers. A study was carried out at Bimbilla in the Nanumba North District of Ghana to evaluate possible interactions of yam genotypes and storage methods for controlling internal rot in yam. Four local varieties (Labalkor, Kplondzo, Olordor and Fushiebila) were studied with four storage methods (barn, pit, platform and heap methods) in a 4 x 4 factorially arrangement. There were significant (P< 0.001) differences among genotypes for resistance to internal rot, with Olordor and Kplondzo recording the lowest internal microbial rot, suggesting their potential in resisting the disease. There were also significant differences (P< 0.05) among the storage methods, with barn and platform being most suitable in reducing the incidence of internal rot in yam. The interaction between yam genotypes and storage methods was not significant (P> 0.05).Le pourrissement microbien apr\ue8s la r\ue9colte est une maladie importante qui cause de pertes s\ue9v\ue8res dans le stockage des ignames ( Dioscorea spp.). Le pourrissement d\ufb \ue0 l\u2019infection microbienne des ignames r\ue9duit leur qualit\ue9 et la pr\ue9f\ue9rence des consommateurs. Une \ue9tude \ue9tait men\ue9e \ue0 Bimbilla dans le District de Nanumba Nord au Ghana pour \ue9valuer des interactions possibles des g\ue9notypes d\u2019ignames et des m\ue9thodes de stockage pour le contr\uf4le du pourrissement interne dans l\u2019igname. Quatre vari\ue9t\ue9s locales, (Labalkor, Kplondzo, Olordor et Fushiebila) \ue9taient \ue9tudi\ue9es avec quatre m\ue9thodes de stockages (m\ue9thodes grange \ue0 igname, silo-fosse, plate forme et tassement) dans un arrangement factoriel 4 x 4. Aucune diff\ue9rence significative (P< 0.001) n\u2019\ue9tait observ\ue9e parmi les g\ue9notypes en rapport avec la r\ue9sistance au pourrissement interne, seuls Olordor et Kplondzo ayant pr\ue9sent\ue9 les taux les moins \ue9lev\ue9s de pourrissement microbien interne, sugg\ue9rant ainsi leur potentiel de r\ue9sistance \ue0 la maladie. Il n\u2019y avait pas aussi de diff\ue9rences significatives (P< 0.05) parmi les m\ue9thodes de stockage, avec grange \ue0 igname et plate forme ayant \ue9t\ue9 les mieux indiqu\ue9es dans la r\ue9duction de l\u2019incidence du pourrissement interne des ignames. L\u2019interaction entre les g\ue9notypes et m\ue9thodes de stockage n\u2019\ue9tait pas significatif (P> 0.05)

Evaluation of tigernut accessions in Ghana for proximate and mineral composition

Tigernut ( Cyperus esculentus L.) is a nutritious, yet underutilised crop in Ghana. The objective of this study was to characterise Ghanaian tigernut accessions for proximate and mineral composition, as a guide for breeders for varietal development. Field and laboratory studies were conducted on 24 tigernut accessions from major growing areas of Ghana. The accessions were cultivated during the minor the growing season (September - November), at the Multipurpose Nursery of the University of Education, Winneba, Asante Mampong in Ghana. The nuts were analysed for proximate (carbohydrate, energy, moisture, ether extract, crude fiber, crude protein and ash) and mineral (potassium, phosphorus and calcium) composition. There were significant (P<0.05) differences among accessions for all traits studied. Accessions were clustered in a dendrogram by colour and geographical origin and PC1 and PC2 explained more than 80% of the total variations among the accessions, with carbohydrate and energy being the major contributors to the total variation. Accessions DY, BKB, KAB, TPY, CCY, WY2 and WY1, which recorded high levels of proximate and mineral compositions, may be considered for breeding programmes to provide high nutrient varieties of tigernut in Ghana.Le Tigernut ( Cyperus esculentus L.) est une culture nutritive mais sous-utilis\ue9e au Ghana. L\u2019objectif de cette \ue9tude \ue9tait de caract\ue9riser les accessions de souchet Ghan\ue9en pour leur composition imm\ue9diate et min\ue9rale, comme un guide pour les s\ue9lectionneurs pour le d\ue9veloppement vari\ue9tal. Des \ue9tudes sur le terrain et en laboratoire ont \ue9t\ue9 men\ue9es sur 24 accessions de souchet provenant des principales zones de culture du Ghana. Les accessions ont \ue9t\ue9 cultiv\ue9es pendant la petite saison de croissance (Septembre - Novembre), \ue0 la p\ue9pini\ue8re polyvalente de l\u2019Universit\ue9 de l\u2019\ue9ducation, Winneba, Asante Mampong au Ghana. Les noix ont \ue9t\ue9 analys\ue9es pour leur composition proche (glucides, \ue9nergie, humidit\ue9, extrait d\u2019\ue9ther, fibres brutes, prot\ue9ines brutes et cendres) et composition min\ue9rale (potassium, phosphore et calcium). Il y avait des diff\ue9rences significatives (P <0,05) entre les accessions pour tous les caract\ue8res \ue9tudi\ue9s. Les accessions ont \ue9t\ue9 regroup\ue9es dans un dendrogramme par couleur et origine g\ue9ographique et PC1 et PC2 expliquaient plus de 80% des variations totales entre les accessions, les glucides et l\u2019\ue9nergie \ue9tant les principaux contributeurs \ue0 la variation totale. Les accessions DY, BKB, KAB, TPY, CCY, WY2 et WY1, qui ont enregistr\ue9 des niveaux \ue9lev\ue9s de composition proximale et min\ue9rale, peuvent \ueatre envisag\ue9es pour des programmes de s\ue9lection afin de fournir des vari\ue9t\ue9s riches en nutriments de tigernut au Ghana

AGROMORPHOLOGICAL CHARACTERISATION OF GBOMA EGGPLANT, AN INDIGENOUS FRUIT AND LEAFY VEGETABLE IN GHANA

Gboma ( Solanum macrocarpon L.) is an important leafy and fruit vegetable in Ghana. Despite its nutritional and medicinal properties, and consumption by many ethnic groups in the country, the crop is underdeveloped. The objective of this study was to characterise diversity among local landraces of Solanum macrocarpon in Ghana using agro-morphological descriptors in order to identify outstanding accessions which could be involved in further breeding programmes. A total of 23 accessions collected from different agro-ecological zones in Ghana were characterised using morphological descriptors. The accessions varied significantly in days to 50% flowering, days to fruiting, stem girth, fruit weight, number of seeds per fruit, weight of leaves per plant and plant height. Principal components analysis based on the morphological traits showed that PC1 for 99% of the total variation was mainly defined by number of leaves, number of branches, plant height, stem girth and number of leaves per plant. The accessions evaluated were grouped under five clusters. The clustering pattern indicated that inter-cluster distance was higher than intra-cluster, indicating wide genetic diversity among the accessions. Correlation analyses between morphological traits revealed positive and negative relationships, indicating predictable success for eventual breeding activities. Accessions CAGRICW3, CAGRICW4, CAGRICN2 and CAGRICA4 had more leaves and fruits, and could be used as potential donors for hybridisation programme to develop variety with higher yield potential.L\u2019aubergine Gboma ( Solanum macrocarpon L.) est un important l\ue9gume feuille et fruit au Ghana. En d\ue9pit de ses propri\ue9t\ue9s nutritionnelle et m\ue9dicinale, et de sa consommation par plusieurs ethnies du pays, cette culture est sous d\ue9velopp\ue9e. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer la diversit\ue9 entre les cultivars traditionnels de Solanum macrocarpon au Ghana en se servant des descripteurs agro morphologiques, dans le but d\u2019identifier des cultivars \ue0 bonne performances agro-morphologiques pouvant \ueatre introduits dans des programmes ult\ue9rieurs d\u2019am\ue9lioration vari\ue9tale. Au total 23 cultivars traditionnels collect\ue9s dans diff\ue9rentes zones agro-\ue9cologiques au Ghana ont \ue9t\ue9 caract\ue9ris\ue9s. Les cultivars ont montr\ue9 une diff\ue9rence significative en ce qui concerne la date de floraison, la date de fructification, la circonf\ue9rence de la tige, le poids du fruit, le nombre de p\ue9pin par fruit, le poids des feuilles par plante et la hauteur des plantes. L\u2019analyse en composantes principales bas\ue9e sur les traits morphologiques montre que le premier axe PC1 comportant 99% de la variation totale \ue9tait essentiellement d\ue9fini par le nombre de feuilles par plante, le nombre de branches, la hauteur des plantes et la circonf\ue9rence de la tige. Les accessions \ue9valu\ue9es ont \ue9t\ue9 group\ue9es en cinq typologies. La r\ue9partition typologique a montr\ue9 que la distance intergroupes \ue9tait plus importante que la distante au sein des groupes, cela sugg\ue8re une grande diversit\ue9 g\ue9n\ue9tique entre les accessions. L\u2019analyse des corr\ue9lations entre traits morphologiques r\ue9v\ue8le des corr\ue9lations positives et n\ue9gatives, ceci indique qu\u2019on peut aboutir \ue0 de bons r\ue9sultats en am\ue9lioration vari\ue9tale. Les cultivars CAGRICW3, CAGRICW4, CAGRICN2 et CAGRICA4 avaient plus de feuilles et de fruits, et de ce fait pourraient \ueatre utilis\ue9s comme potentiel parents dans des programmes d\u2019am\ue9lioration vari\ue9tale pour d\ue9velopper des vari\ue9t\ue9s \ue0 haut rendement

Identifying heterotic groups and testers for hybrid development in early maturing yellow maize (Zea mays) for sub-Saharan Africa

Open Access ArticleIdentification of heterotic groups and efficient testers, which are important prerequisites for the development of outstanding hybrids, has been a major challenge to its success, especially for early and extra‐early germplasm. This study was carried out to (a) identify the most efficient heterotic grouping method for classifying a set of inbred lines and (b) determine the efficiency of testers in classifying inbred lines into heterotic groups. A total of 205 hybrids obtained by crossing 41 inbred lines with five standard testers were evaluated together with five hybrid checks under drought, low soil nitrogen (N), Striga‐infested and optimal environments in Nigeria between 2014 and 2016. The heterotic group's specific and general combining ability (HSGCA) method was more effective in classifying the inbred lines into heterotic groups. Testers TZEI 17 and TZEI 23 were the most efficient across environments and could be invaluable for classifying other lines into heterotic groups and assessing combining ability of maize inbreds. In addition, these testers and heterotic groups represent an invaluable resource for development of outstanding hybrids in sub‐Saharan Africa (SSA)

Testcross performance and combining ability of early maturing maize inbreds under multiple-stress environments

Open Access Journal; Published online: 24 Sept 2019Availability of multiple-stress tolerant maize is critical for improvement in maize production in West and Central Africa (WCA). A study was carried out to (i) assess a set of inbred lines for combining ability under stressed and optimal conditions, (ii) determine the performance of the testcrosses under different conditions, and (iii) identify outstanding hybrids across the conditions. Two hundred and five testcrosses were planted with five hybrid checks under Striga-infested, low soil nitrogen, drought and optimal conditions between 2015 and 2016 in Nigeria. The grain yield inheritance under optimal condition was largely regulated by additive gene effect whereas non-additive gene effects largely regulated grain yield under the three stresses. Four of the inbreds had significant positive general combining ability effects each under low N and drought, and three under Striga infestation for grain yield. The inbreds could be vital sources of beneficial alleles for development and improvement of tropical yellow maize hybrids and populations. Hybrids TZEI 443 x ENT 13 and TZEI 462 x TZEI 10 were high yielding and stable; they out-performed the three early maturing released hybrids in WCA. The new hybrids should be extensively assessed and released in the sub-region to improve food security

Nutritional and antioxidant composition of eggplant accessions in Ghana

Eggplants ( Solanum spp.) are important vegetable crops, well known for nutritional and medicinal values of their fruits and leaves. In order to select more nutritious varieties in Ghana, 33 eggplant accessions were investigated for nutritional, mineral and antioxidant content of their fruits. Proximate and antioxidant analysis were determined by AOAC and DPPH methods. The results showed significant differences (P<0.05) among nutritional, mineral and antioxidant traits. Most accessions contained high moisture content (above 70%). Nutrient concentrations ranged from 0.10 fat to 6.10 g 100 g-1 carbohydrate; and 0.107 magnesium to 11.271 mg 100 g-1 iron. Total phenolic content was highest in accession ST004-03 (210 mg GAE g-1 (gallic acid equivalent), and lowest in SA002-02 (171.10 mg GAE g-1). Accessions ST004-02 and ST004-03 displayed the highest DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical scavenging activity (0.017 mg ml-1); while San 005-01 (1474 mg ml-1) showed the highest antioxidant content. Principal component analysis indicated that the first 3 components with Eigen value >1.5 contributed 68.68% of total variability. Dry matter, protein, moisture and carbohydrate contents showed maximum contributions to the total variability. Biplot analysis displayed strong and positive associations among ash, protein and moisture with dry matter; moisture and carbohydrate and; protein and ash. Accessions San 005-01, San 005-02, SA 002-07, SA 002-08 and ST004-03 were identified as good sources of nutrients, minerals and antioxidant properties among the others; and could be used as potential donors for hybridisation programme to develop varieties with higher concentration of these traits.Les aubergines ( Solanum spp.) Sont des cultures l\ue9gumi\ue8res importantes, bien connues pour les valeurs nutritionnelles et m\ue9dicinales de leurs fruits et de leurs feuilles. Pour s\ue9lectionner des vari\ue9t\ue9s plus nutritives au Ghana, 33 accessions d\u2019aubergines ont \ue9t\ue9 \ue9tudi\ue9es pour d\ue9terminer la teneur nutritionnelle, min\ue9rale et antioxydante de leurs fruits. Les analyses proximale et antioxydante ont \ue9t\ue9 d\ue9termin\ue9es par les m\ue9thodes AOAC et DPPH. Les r\ue9sultats ont montr\ue9 des diff\ue9rences significatives (P <0,05) entre les caract\ue9ristiques nutritionnelles, min\ue9rales et antioxydantes. La plupart des accessions avaient une teneur en eau \ue9lev\ue9e (sup\ue9rieure \ue0 70%). Les concentrations de nutriments allaient de 0,10 \ue0 6,10 g de glucides \ue0 100 g-1; et 0,107 magn\ue9sium \ue0 11,271 mg 100 g-1 de fer. La teneur totale en compos\ue9s ph\ue9noliques \ue9tait la plus \ue9lev\ue9e lors de l\u2019accession ST004-03 (210 mg GAE g-1 (\ue9quivalent d\u2019acide gallique) et la plus faible dans le SA002-02 (171,10 mg GAE g-1). Les accessions ST004-02 et ST004-03 ont pr\ue9sent\ue9 l\u2019activit\ue9 de pi\ue9geage de radicaux DPPH (2,2-diph\ue9nyl-1-picrylhydrazyle) la plus \ue9lev\ue9e (0,017 mg ml-1); tandis que San 005-01 (1474 mg ml-1) pr\ue9sentait la plus forte teneur en antioxydants. L\u2019analyse des composantes principales a montr\ue9 que les 3 premi\ue8res composantes avec une valeur propre sup\ue9rieure \ue0 1,5 ont contribu\ue9 \ue0 68,68% de la variabilit\ue9 totale. Les teneurs en mati\ue8re s\ue8che, en prot\ue9ines, en humidit\ue9 et en glucides ont contribu\ue9 au maximum \ue0 la variabilit\ue9 totale. L\u2019analyse bi-parcelle a montr\ue9 des associations fortes et positives entre les cendres, les prot\ue9ines et l\u2019humidit\ue9 avec la mati\ue8re s\ue8che, l\u2019humidit\ue9 et les glucides; prot\ue9ines et cendres. Les accessions San 005-01, San 005-02, SA 002-07, SA 002-08 et ST004-03 ont \ue9t\ue9 identifi\ue9es comme \ue9tant de bonnes sources d\u2019\ue9l\ue9ments nutritifs, de min\ue9raux et de propri\ue9t\ue9s antioxydantes; et pourrait \ueatre utilis\ue9 comme donneur potentiel pour le programme d\u2019hybridation visant \ue0 d\ue9velopper d\ue9velopper des vari\ue9t\ue9s avec une concentration plus \ue9lev\ue9e de ces caract\ue8res

Gene effect and heritability of yield and its components in eggplant

Eggplant ( Solanum melongena L.) is one of the most important fruit vegetables in the world, with several nutritional and medicinal benefits. However, little is known about the genetic divergence of yield and its related traits. The objective of this study was to explore gene action and heritability of traits to help direct and strengthen breeding programmes, geared towards improving yield of the crop. Six generations (P1, P2, F1, F2, BC1 and BC2) derived from two crosses (SM001-07 x ST004-03 and SM001 x San005-01) of eggplant accessions, were grown in pots in an open field, using Randomised Complete block Design (RCBD). Estimated data indicated that, the additive-dominance model was adequate to demonstrate the genetic variation and its significance in the inheritance of fruit weight, days to flowering and fruit yield traits. Although non-allelic interactions were found in plant height and number of seeds, additive effect was more pronounced in the genetic control of days to flowering and fruit weight; while dominance effect was more important in the control of plant branching and fruit length. Plant height and fruit yield were influenced by complementary gene action. Furthermore, the study revealed low magnitudes of dominance and environmental variances for most traits showing higher heritability values. In view of the diverse gene actions, with additive, dominant and epistasis, playing significant roles in the control of different traits, backcross, recurrent selection or bi parental could be appropriate for advancing the segregating populations to meet the need of yield improvement in both crosses.L\u2019aubergine ( Solanum melongena L.) est l\u2019un des legumes fruits les plus importants au monde, avec les plusieurs bienfaits nutritionnels et m\ue9dicinaux. Cependant, on sait peu de choses sur la divergence g\ue9n\ue9tique du rendement et ses traits li\ue9s. L\u2019objectif de cette \ue9tude \ue9tait d\u2019explorer l\u2019action des g\ue8nes et l\u2019h\ue9ritabilit\ue9 des traits pour aider \ue0 diriger et \ue0 renforcer les programmes de s\ue9lection visant \ue0 am\ue9liorer le rendement de la culture. Six g\ue9n\ue9rations (P1, P2, F1, F2, BC1 et BC2) d\ue9riv\ue9es de deux croisements (SM001-07 x ST004-03 et SM001 x San005-01) d\u2019accessions d\u2019aubergines ont \ue9t\ue9 cultiv\ue9es en pots dans un champ. Les donn\ue9es estim\ue9es indiquent que le mod\ue8le de dominance additive \ue9tait ad\ue9quat pour d\ue9montrer la variation g\ue9n\ue9tique et son importance dans l\u2019h\ue9r\ue9dit\ue9 du poids du fruit, des jours de floraison et des traits de rendement des fruits. Bien que des interactions non all\ue9liques aient \ue9t\ue9 trouv\ue9es dans la hauteur des plantes et le nombre de graines, l\u2019effet additif \ue9tait plus prononc\ue9 dans le contr\uf4le g\ue9n\ue9tique des jours de floraison et du poids des fruits; tandis que l\u2019effet de dominance \ue9tait plus important dans le contr\uf4le de la ramification des plantes et de la longueur des fruits. La hauteur des plantes et le rendement des fruits ont \ue9t\ue9 influenc\ue9s par l\u2019action compl\ue9mentaire des g\ue8nes. De plus, l\u2019\ue9tude a r\ue9v\ue9l\ue9 de faibles variation de dominance et des variances environnementales pour la plupart des traits pr\ue9sentant des valeurs d\u2019h\ue9ritabilit\ue9 plus \ue9lev\ue9es. Compte tenu des diverses actions des g\ue8nes, avec additif, dominant et \ue9pistase, jouant un r\uf4le important dans le contr\uf4le des diff\ue9rents traits, le r\ue9trocroisement, la s\ue9lection r\ue9currente ou biparentale pourrait \ueatre appropri\ue9 pour faire progresser les populations en s\ue9gr\ue9gation afin de r\ue9pondre au besoin d\u2019am\ue9liorer le rendement dans les deux croisements

COMBINING ABILITY AND GENETIC ANALYSIS OF FRUIT AND LEAF YIELD IN GBOMA EGGPLANT

Gboma eggplant ( Solanum macrocapon L.) of the family Solanaceae is an important fruit and leafy indigenous vegetable in Africa. Despite the numerous nutritional, medicinal and economic benefits derived from the crop, little is known about the genetic parameters governing the inheritance and combining ability of the yield components. Thus, a study was conducted to investigate genetic information on the relevant yield components of the crop. Results showed significant mean squares for General Combining Ability, Specific Combining Ability effects for number of leaves per plant, fruit width and plant height, indicating the combining effect of additive, non-additive and maternal effects for expression for those traits. Conversely, significant (P< 0.05) SCA effects for number of branches per plant, leaf length, leaf width and fresh leaf weight indicated the preponderance of non-additive gene effect. GCA/SCA ratios for the various traits indicated that the relative contribution of additive to non-additive effects varied widely from trait to trait. Significant reciprocal effects for most of the traits were an indication that cytoplasmic or maternal gene effects played a major role in modifying the inheritance of the yield parameters, and that the choice of the maternal parent is relevant in breeding for these traits. Estimated GCA effect among the parents revealed that CAGRIC 03 has a breeding value for number of branches, plant height, fruit length, leaf length and fresh leaf weight, which makes it a valuable material for development of improved varieties. CAGRIC 01 was the promising combiner to increase fruit weight and number of leaves per plant. Hybrid P1xP2 was the best specific combiner to increase fruit width, leaf width and fruit width. High heritability estimates for most of the traits indicate that genetic variation was higher than the environmental variation in the study.Aubergine gboma ( Solanum macrocapon L.) de la famille des solanac\ue9esest un fruit important et l\ue9gumes indig\ue8nes feuillues en Afrique. Malgr\ue9 de nombreux avantages nutritionnels, m\ue9dicinaux et \ue9conomiques d\ue9coulant de la culture, peu est connu sur les param\ue8tres g\ue9n\ue9tiques r\ue9gissant l\u2019h\ue9ritage et la capacit\ue9 de combinaison des composants de rendement. Ainsi, une \ue9tude \ue9tait initi\ue9e pour g\ue9n\ue9rer del\u2019information g\ue9n\ue9tique sur d\u2019importants composants de rendementde la culture. Les r\ue9sultats ont montr\ue9 des carr\ue9s moyens significatifs pour \ue0 l\u2019aptitude generale de combinaison, les effets de la capacit\ue9 sp\ue9cifique de combinaison pour le nombre de feuilles par plante, la largeur des fruits et la hauteur de plant, ce qui t\ue9moign edes effets additifs et non additif et maternels combin\ue9s pour l\u2019expression de ces traits. Inversement, les effets significatifs (P <0,05) de CCSsur le nombre de branches par plant, la longueuret la largeur des feuilles ainsi que le poids de feuilles fra\ueeches indiquent la pr\ue9pond\ue9rance de l\u2019effet du g\ue8ne non-additif. Les rapports GCA/SCA pour les diff\ue9rents traits indiquent que la contribution relative de l\u2019additif aux effets non additifs variait largement d\u2019un trait \ue0 l\u2019autre. Des effets r\ue9ciproques significatifs pour la plupart des traits indiqueque les effets g\ue9n\ue9tiques cytoplasmique sou maternels ont jou\ue9 un r\uf4le majeur dans la modification de l\u2019h\ue9ritage des param\ue8tres de rendement et que le choix du parent maternel est pertinent dans l\u2019am\ue9lioration de ces traits. L\u2019effetestim\ue9 deGCA chez les parents a r\ue9v\ue9l\ue9 que CAGRIC 03 est d\u2019 une valeur ameliorative pour le nombre de branches, la hauteur de la plante, la longueur des fruits, la longueur des feuilles et le poids des feuilles fra\ueeches, ce qui en fait un mat\ue9riel pr\ue9cieux pour le d\ue9veloppement de vari\ue9t\ue9s am\ue9lior\ue9es. CAGRIC 01 \ue9tait le combinateur prometteur pour augmenter le poids de fruits et le nombre de feuilles par plant. L\u2019hybride P1xP2 \ue9tait le meilleur combineur sp\ue9cifique pour augmenter la largeur du fruit, la largeur des feuilles et la largeur du fruit. Des valeurs \ue9lev\ue9es d\u2019h\ue9ritabilit\ue9 pour la plupart des traits indiquent que la variation g\ue9n\ue9tique \ue9tait plus \ue9lev\ue9e que la variation environnementale dans l\u2019\ue9tude

The international Perinatal Outcomes in the Pandemic (iPOP) study: protocol

Preterm birth is the leading cause of infant death worldwide, but the causes of preterm birth are largely unknown. During the early COVID-19 lockdowns, dramatic reductions in preterm birth were reported; however, these trends may be offset by increases in stillbirth rates. It is important to study these trends globally as the pandemic continues, and to understand the underlying cause(s). Lockdowns have dramatically impacted maternal workload, access to healthcare, hygiene practices, and air pollution - all of which could impact perinatal outcomes and might affect pregnant women differently in different regions of the world. In the international Perinatal Outcomes in the Pandemic (iPOP) Study, we will seize the unique opportunity offered by the COVID-19 pandemic to answer urgent questions about perinatal health. In the first two study phases, we will use population-based aggregate data and standardized outcome definitions to: 1) Determine rates of preterm birth, low birth weight, and stillbirth and describe changes during lockdowns; and assess if these changes are consistent globally, or differ by region and income setting, 2) Determine if the magnitude of changes in adverse perinatal outcomes during lockdown are modified by regional differences in COVID-19 infection rates, lockdown stringency, adherence to lockdown measures, air quality, or other social and economic markers, obtained from publicly available datasets. We will undertake an interrupted time series analysis covering births from January 2015 through July 2020. The iPOP Study will involve at least 121 researchers in 37 countries, including obstetricians, neonatologists, epidemiologists, public health researchers, environmental scientists, and policymakers. We will leverage the most disruptive and widespread “natural experiment” of our lifetime to make rapid discoveries about preterm birth. Whether the COVID-19 pandemic is worsening or unexpectedly improving perinatal outcomes, our research will provide critical new information to shape prenatal care strategies throughout (and well beyond) the pandemic

Changes in preterm birth and stillbirth during COVID-19 lockdowns in 26 countries

Preterm birth (PTB) is the leading cause of infant mortality worldwide. Changes in PTB rates, ranging from −90% to +30%, were reported in many countries following early COVID-19 pandemic response measures (‘lockdowns’). It is unclear whether this variation reflects real differences in lockdown impacts, or perhaps differences in stillbirth rates and/or study designs. Here we present interrupted time series and meta-analyses using harmonized data from 52 million births in 26 countries, 18 of which had representative population-based data, with overall PTB rates ranging from 6% to 12% and stillbirth ranging from 2.5 to 10.5 per 1,000 births. We show small reductions in PTB in the first (odds ratio 0.96, 95% confidence interval 0.95–0.98, P value <0.0001), second (0.96, 0.92–0.99, 0.03) and third (0.97, 0.94–1.00, 0.09) months of lockdown, but not in the fourth month of lockdown (0.99, 0.96–1.01, 0.34), although there were some between-country differences after the first month. For high-income countries in this study, we did not observe an association between lockdown and stillbirths in the second (1.00, 0.88–1.14, 0.98), third (0.99, 0.88–1.12, 0.89) and fourth (1.01, 0.87–1.18, 0.86) months of lockdown, although we have imprecise estimates due to stillbirths being a relatively rare event. We did, however, find evidence of increased risk of stillbirth in the first month of lockdown in high-income countries (1.14, 1.02–1.29, 0.02) and, in Brazil, we found evidence for an association between lockdown and stillbirth in the second (1.09, 1.03–1.15, 0.002), third (1.10, 1.03–1.17, 0.003) and fourth (1.12, 1.05–1.19, <0.001) months of lockdown. With an estimated 14.8 million PTB annually worldwide, the modest reductions observed during early pandemic lockdowns translate into large numbers of PTB averted globally and warrant further research into causal pathways