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Tracking down the changes in maize participatory breeding: Portuguese “Amiúdo” and “Castro Verde” populations

Portugal has a long term participatory plant breeding (PPB) programme running since 1984 – the VASO project. This project aims on increasing yield and improving quality of local maize landraces known for their ability for bread production, while respecting traditional agriculture, accepting low input and intercropping, and favouring diversity in a way that local genetic resources could be competitive and maintained on-farm. Our objectives were to evaluate the impact of VASO PPB approach at molecular and phenotypic level. For that we analysed the genetic, agronomic and quality evolution of two regional OPV populations that integrated this project: “Amiúdo”, a yellow flint early maturity variety (FAO 200), adapted to stress conditions (aluminium toxicity and water deficit) ; and “Castro Verde”, a orange flint late maturity variety (FAO 600), characterized for having taller plants (Mendes-Moreira, 2006). Both populations were expected to be potentially interesting for food and “Castro Verde” for a double food and feed use. Using 20 SSR uniformly distributed throughout the genome, we genotyped 30 individuals from three selection cycles of “Castro Verde” population (representing 15 years of on-farm mass selection) and three selection cycles of the “Amiúdo” population (representing 25 years of on-farm mass selection) comparing the later with the third cycle of the breeder’s recurrent selection by S1 lines. Yield, technological (e.g. flour viscosity), nutritional (fibre, fat and protein) and organoleptic (carotenoids, phenolics and antioxidant activity) quality traits were also studied on the same selection cycles. Multi-location trials (6-9 locations) were established for yield evaluation, being the samples for quality evaluation collected from one only location. Allelic richness and gene diversity will be assessed for each cycle, and genic and genotypic differentiation among cycles tested. Regression analysis on the yield response to selection will be discussed. AMOVA will be used to partition the total genetic variance according to the available phenotypic data, as well as to study the genetic diversity within and among different selection cycles. This analysis is fundamental to clarify if this PPB program is being successful in conserving diversity and improving quality and yield on these two OPVs as it was already shown for the “Pigarro” OPV’s genetic diversity conservation, also breed under this approach (Vaz Patto et al., 2008).

participatory plant breeding; open-pollinated varieties; selection cycles; quality traits; SSRs

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