engleski

Genetic Diversity Evolution thorugh Participatory Maize Breeding

Maize arrived in Portugal from America during the XVI century and spread rapidly throughout the country. Numerous open pollinated traditional varieties (landraces) have been developed during the centuries of cultivation, adapted to specific regional growing conditions as well as farmer’ s needs, and represent a valuable genetic resource for breeding and genetic studies. Concern has been expressed that genetic diversity might be reduced by natural and artificial (human) selection. However, traditional Portuguese farmers were trained to preserve variability as a way to guarantee production under any circumstance. In 1984, P&ecirc ; go started, with CIMMYT support, an on-farm participatory maize breeding project at the Portuguese Sousa Valley region (VASO). It concerned mainly flint-type open pollinated landraces with technological ability for production of the traditional maize bread called “ broa” . “ Broa” production still plays an important economic and social role in Central and Northern Portuguese rural communities. This bread making ability depends on a range of particular traits not found on the available commercial hybrid varieties and this is probably why traditional maize landraces have not, in these regions, been totally replaced by hybrid varieties. In the VASO project, a particular landrace ‘ Pigarro’ was selected from the traditional populations cultivated in this region. Participatory plant breeding using mass selection was carried out each year and seed was stored from each selection cycle. Production and ear size increased and root lodging decreased along this selection process. Our present objective is to evaluate the impact of participatory plant breeding upon ‘ Pigarro’ genetic diversity over an interval of 20 years of selection. For this purpose, 30 randomly selected individuals from each of three different selection cycles (1984, 1993 and 2004) were fingerprinted with 10 SSR markers uniformly distributed across the maize genome. Allelic richness and gene diversity will be assessed for each selection cycle and genic and genotypic differentiation among cycles will be tested and discussed.

participatory plant breeding; maize; open-pollinated varieties; genetic diversity

nije evidentirano