Caractérisation botanique et agronomique de trois espèces de cucurbites consommées en sauce en Afrique de l'Ouest : Citrullus sp., Cucumeropsis mannii Naudin et Lagenaria siceraria (Molina) Standl

Botanical and agronomical characterisation of three species of cucurbit consumed as sauce in West Africa: Citrullus sp., Cucumeropsis mannii Naudin and Lagenaria siceraria (Molina) Standl. There are in Côte d'Ivoire at least five species of cucurbit incorrectly called ""pistaches"" in town and cultivated at small scale by women for their oleaginous seeds that are a great importance in the sociocultural live of several peoples. Nevertheless, few studies aimed at the improvement of these plants (related notably to taxonomy, genetic resources collecting missions, genetic characterisation, agronomic evaluation, and selection) have been carried out. In order to set up a list of reliable traits that should be examined easily during and after collecting missions, we carry out in the present study, for three species (Citrullus sp., Cucumeropsis mannii Naudin and Lagenaria siceraria (Molina) Standl) a botanic description and an analysis of eleven agronomic traits: 100-seeds weight, germination rate, seedlings emergence time, matured fruit weight, matured fruit decomposition time, mean number of seeds per fruit, seeds shape, fruit diameter, fruit interior cavity diameter, flowering time, and fruiting time. Statistical analyses using nine of these traits showed that the three species can be completely distinguished with six traits whereas the three other traits allowed partial distinction. Low yields have been observed for the three species: 11.41 kg/ha of decorticated seeds for C. mannii, 18.51 kg/ha for Citrullus sp. and 75.14 kg/ha for L. siceraria. From the observed yield components, the possibilities to improve the production of these cucurbits are discussed

Heritability and number of genes controlling seed yield in bottle gourd

Bottle gourd [ Lagenaria siceraria (Molina) Standley] is an important tropical specie characterised by a wide diversity and a low yield, mainly due to no selection for improved varieties. Selection for a particular trait depends on the relative importance of genetic and nongenetic factors influencing the expression of phenotypic differences among crop population. The objective of this study was to examine the genetics basis of seed yield and yield components, by crossing oleaginous type and calabash-type of bottle gourd [Lagenaria siceraria (Molina) Standley]. The parental lines (P1 and P2), with the respective hybrids F1 and F2 generations, were grown in two contrasted locations in terms of pedoclimatic conditions. Results showed no significant difference between the two locations for studies traits (P=0.06). For seed yield per plant, 100-seed weight per fruit, and number of seeds per fruit, a positive hypothetical heterosis was observed when calabash type was a maternal parent. Negative real heterosis was observed in all studied traits. For all traits, the genetic variance was higher than the environmental variance in the most of the crosses, implying greatest genes action in the expression of studies traits. Heritability was medium for fruit weight (mean, 42.12%) and seed number per fruit (mean, 47.36%). But for 100-seed weight (mean, 61.00%) and seed yield per plant (mean, 53.28%) high heritability were observed. The minimum number of genes that controlled the expression of 100-seed weight (0.58), seed yield per plant (1.58) and number of seeds per plant (0.98) was low (close to 1). These observations suggest that distinct genotypes for interest characters would be fixed by using a small number of selfing generations (F3 to F4) in West African bottle gourd.La gourde ol\ue9agineuse est une esp\ue8ce tropicale caract\ue9ris\ue9e par une grande diversit\ue9 agromorphologique et un faible rendement qui s\u2019explique par l\u2019absence de s\ue9lection pour les vari\ue9t\ue9s am\ue9lior\ue9es. La s\ue9lection d\u2019un caract\ue8re d\u2019int\ue9r\ueat d\ue9pend de l\u2019importance relative des facteurs g\ue9n\ue9tiques et non g\ue9n\ue9tiques qui influencent l\u2019expression des diff\ue9rences ph\ue9notypiques observ\ue9es dans la population \ue9tudi\ue9. L\u2019objectif de cette \ue9tude est d\u2019examiner les bases g\ue9n\ue9tiques et le nombre de g\ue8nes contr\uf4lant le rendement en graines et ses composantes en croisant quatre accessions de Lagenaria siceraria (Molina) Standley\ua0: deux du type calebasse (NI-CM001 et NI-CSM001) et deux du type ol\ue9agineux (NI-232 et NI-135). Pour se fait, les lign\ue9es parentales (P1 et P2) et les g\ue9n\ue9rations hybrides (F1 et F2) ont \ue9t\ue9 cultiv\ue9s sur deux sites contrast\ue9s (nord et sud de la C\uf4te d\u2019Ivoire). Les r\ue9sultats de l\u2019analyse multivari\ue9 de la variance (MANOVA) n\u2019ont montr\ue9 aucune diff\ue9rence significative entre les deux sites pour l\u2019ensemble des caract\ue8res \ue9tudi\ue9s (F = 2,29; P = 0,06). L\u2019h\ue9t\ue9rosis th\ue9orique (parent moyen) \ue9tait positive lorsque le type de calebasse servait de parent maternel pour le poids de 100 graines par fruit, le rendement des graines par plante et le nombre de graines par fruit, alors que l\u2019h\ue9t\ue9rosis r\ue9elle (meilleur parent) \ue9tait n\ue9gative pour ces caract\ue8res. L\u2019h\ue9ritabilit\ue9 \ue9tait moyenne pour le poids des fruits (42,12%) et le nombre de graines par fruit (47,36%). Cependant, une forte h\ue9ritabilit\ue9 a \ue9t\ue9 observ\ue9e pour le poids de 100 graines (61,00%) et le rendement en graines par plante (53,28%). Un faible nombre g\ue8nes a \ue9t\ue9 observ\ue9 dans l\u2019expression de la masse de 100 graines (0,58), le rendement en graines par plante (1,58) et le nombre de graines par plante (0,98). Ces r\ue9sultats sugg\ue8rent que dans les programmes futurs d\u2019am\ue9lioration de L. siceraria, la s\ue9lection des g\ue9notypes les plus performants pour les composantes du rendement pourrait se faire d\ue8s les g\ue9n\ue9rations d\u2019autof\ue9condation F3 ou F4

Effect of intensity and timing of defoliation on seed yield and yield components in oilseed gourd and its implication in insect pests\u2019 sustainable control

Dual-purpose cropping for both leaf and seed production can be highly profitable if leaf removal by pests or farmers does not cause significant loss of seed yield. The objective of this study was to access the effect of defoliation intensity and timing on 7 yield and yield components for the cucurbit Lagenaria siceraria . The study was done in 2013 and 2014. Four defoliation intensities (0, 25, 50 and 75%) were applied to the crop at three phenological stages (tendril, flowering and fruit setting stage) in a split plot design. For all the yield traits examined, no significant difference was found between the control and 25% leaf defoliation, whatever the plant phenological stage. However, intense defoliation negatively affected seed production (from 1.99\ub10.98 t ha-1 with the control to 1.41\ub11.07 t ha-1 with 75% defoliation), irrespective of the growth stage of the plant. Seed yield decreased when defoliation was applied at advanced phenological stage, varying from a mean of 1.99\ub10.98 t ha1 (tendril) to 1.55\ub10.34 t ha-1 (fruit setting). The results suggested that the intensity of defoliation when harvesting the leaves or to trigger the treatment of bottle gourd against leaves damaging pests is about 25%, whatever the timing.Une culture \ue0 double usage pour la production de feuilles et de semences peut \ueatre tr\ue8s rentable si l\u2019\ue9limination des feuilles par des organismes nuisibles ou des agriculteurs ne provoque pas de perte significative de rendement en semences. L\u2019objectif de cette \ue9tude \ue9tait de d\ue9terminer l\u2019effet de l\u2019intensit\ue9 de la d\ue9foliation et de la synchronisation sur le rendement et les composantes du rendement pour la cucurbitac\ue9e Lagenaria siceraria . L\u2019\ue9tude a \ue9t\ue9 r\ue9alis\ue9e en 2013 et 2014. Quatre intensit\ue9s de d\ue9foliation (0, 25, 50 et 75%) ont \ue9t\ue9 appliqu\ue9es \ue0 la culture \ue0 trois stades ph\ue9nologiques (stade vrille, floraison et nouaison) en parcelles divis\ue9es. Pour toutes les caract\ue9ristiques de rendement examin\ue9es, aucune diff\ue9rence significative n\u2019a \ue9t\ue9 observ\ue9e entre la d\ue9foliation t\ue9moin et la d\ue9foliation foliaire \ue0 25%, quel que soit le stade ph\ue9nologique de la plante. Cependant, une d\ue9foliation intense a eu un effet n\ue9gatif sur la production de semences (de 1,99 \ub1 0,98 t ha-1 avec le t\ue9moin \ue0 1,41 \ub1 1,07 t ha-1 avec une d\ue9foliation \ue0 75%), quel que soit le stade de croissance de la plante. Le rendement en semences diminuait lorsque la d\ue9foliation \ue9tait appliqu\ue9e \ue0 un stade ph\ue9nologique avanc\ue9, variant entre une moyenne de 1,99 \ub1 0,98 t ha-1 (vrille) \ue0 1,55 \ub1 0,34 t ha-1 (nouaison). Les r\ue9sultats sugg\ue8rent que l\u2019intensit\ue9 de la d\ue9foliation lors de la r\ue9colte des feuilles ou pour d\ue9clencher le traitement de la gourde contre les ravageurs nuisibles aux feuilles est d\u2019environ 25%, quel que soit le moment

Effet de la Saison de Culture et de la Densité des Plants sur les Adventices et la Production de la Cucurbite oléagineuse Citrullus lanatus (Thunberg) Matsum. & Nakai (Cucurbitaceae)

peer reviewe

Genetic characterization of oleaginous bottle gourd (Lagenaria siceraria) germplasm from Côte d'Ivoire using agromorphological and molecular markers

Being difficult to regenerate and maintain the seeds, the oleaginous bottle gourd was investigated using nine agromorphological traits and 31 amplified fragment length polymorphism (AFLP) markers. Specifically, the study was conducted to determine the intra-specific variability of a total of 173 accessions, which were identified from five agro-ecological regions from Côte d'Ivoire (Centre, East, North and South). Then, the genetic diversity and relationships within accessions were studied using AFLP markers. This characterization using both morphological and AFLP markers was realized in order to ultimately build a reliable core collection. The discriminant analysis, using nine quantitative traits, reveals plant length and seeds number per fruit as discriminating characteristics. From the accessions used for the agromorphological study, 148 were able to be differentiated by the AFLP markers. A range of 52 to 113 bands were amplified per primer combination. As revealed by the analysis of molecular variance (AMOVA), 28% of the total variation resides among accessions and 72% occurs within populations. The AMOVA computed in order to differentiate cultivars, displayed the same trends when no prior grouping of accessions was considered. The differentiation within cultivar (97%) was more than that, among cultivars (3%). Tree topologies inferred by neighbour-joining analysis reflected no clear cut off grouping

Detection and identification of the coconut lethal yellowing phytoplasma in weeds growing in coconut farms in C\uf4te d\u2019Ivoire

Coconut farms located in the southern coast of Grand-Lahou in C\uf4te d\u2019Ivoire are severely affected by a lethal yellowing disease (CILY) associated with the group 16SrXXII-B, \u2018Candidatus Phytoplasma palmicola\u2019-related strains. Given the high prevalence of weed species on most of the farms, plants growing within and in the periphery of five selected coconut farms were assessed for the presence of the CILY phytoplasma to identify potential alternative hosts. A total of 396 plant samples belonging to 84 plant species and 35 botanical families were collected. Total DNA was extracted and tested by nested PCR with primers targeting the 16S rRNA and the translocation protein (secA) phytoplasma genes, and sequenced. Twenty samples from six plant species and five botanical families yielded PCR amplicons of the expected size, and both the secA and 16S rDNA sequences showed over 99% similarity with that of the C\uf4te d\u2019Ivoire lethal yellowing phytoplasma previously identified from coconut palms grown in Grand-Lahou coconut farms. Plant species from the families Poaceae (Paspalum vaginatum, Pennisetum pedicillatum), Verbenaceae (Stachytarpheta indica), Plantaginaceae (Scoparia dulcis), Phyllanthaceae (Phyllantus muellerianus) and Cyperacea (Diplacrum capitatum) were positive for the presence of the CILY phytoplasma, suggesting they may have epidemiological implications for disease spread in coconut farms in Grand-Lahou

Correction to: Is diet partly responsible for differences in COVID-19 death rates between and within countries? (Clinical and Translational Allergy, (2020), 10, 1, (16), 10.1186/s13601-020-00323-0)

Following publication of the original article [1], the authors identified an error in the affiliation list. The affiliation of author G. Walter Canonica should have been split up into two affiliations: • Personalized Medicine, Asthma and Allergy – Humanitas Clinical and Research Center – IRCCS, Rozzano (MI), Italy • Department of Biomedical Sciences, Humanitas University, Pieve Emanuele (MI), Italy The corrected affiliation list is reflected in this Correction. © 2020, The Author(s)