Conservative selection of a population variety of zucchini according to its genetic and phenotypic diversity analysis

Gautier L., Broucqsault L.M., Kahane Rémi, Malicet-Chebbah L., Crosnier-Mangeat C.. 2023. Conservative selection of a population variety of zucchini according to its genetic and phenotypic diversity analysis. In : Proceedings of the International Symposium on Conservation and Sustainable Use of Horticultural Genetic Resources. Ulian T. (ed.), Noorania A. (ed.), Morillon R. (ed.). ISHS. Louvain : ISHS, 97-104. (Acta Horticulturae, 1384) ISBN 978-94-6261-383-6 International Horticultural Congress (IHC2022): International Symposium on Conservation and Sustainable Use of Horticultural Genetic Resources. 31, Angers, France, 14 Août 2022/20 Août 2022.

Résumé : The management of Cucurbita population varieties is complex because of their genetic and phenotypic heterogeneity. In organic agriculture, this heterogeneity is sought for adaptation to various stresses. This question is central for the multiplication of quality farmer seeds as well as for plant materials adapted to a tropical context such as in West Africa. A research program was initiated by the seed company Agrosemens, supported by the Institut Agro of Montpellier and CIRAD, to characterize the criteria to consider in maintenance breeding. For this purpose, an experimental protocol was set up with the zucchini cultivar 'Black Beauty', propagated for 4 years at Agrosemens, with 2 contrasting watering regimes. The study of these four generations intends to identify the impact of practices of the various farmers involved in the propagation of this cultivar. Five other seed batches from different origins were used. A field trial was set up to analyse phenotypic diversity within and between seed lots, and to analyse genetic diversity from the DNA of sampled individuals. Of the 23 recorded phenotypic traits, 13 were retained after estimation of correlations. The seed lots were then grouped into clusters according to their genotypes. The intra- and inter-lot diversity was analysed using 8 SSR markers thanks to F-statistics, and confirmed the relevance of the typology based on DPCA clusters. In fine, large differences, both genetic and phenotypic, were observed between the lots. The effect of agronomic practices, including the number of multiplications, on genetic diversity and trait conservation was significant. In contrast, the two watering regimes did not generate significant differences between the seed batches on the observed criteria. This study has laid the foundation for a maintenance breeding strategy for Cucurbita population varieties and will be continued.

Mots-clés libres : Farmer seed systems, Breeding strategies, Open pollinated varieties

Auteurs et affiliations

• Gautier L., Agrosemens (FRA)
• Broucqsault L.M., Agrosemens (FRA)
• Kahane Rémi, CIRAD-PERSYST-UPR HortSys (FRA) ORCID: 0000-0001-5492-2834
• Malicet-Chebbah L., Institut Agro Montpellier (FRA)
• Crosnier-Mangeat C., Agrosemens (FRA)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/607896/)

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