Characterization and Valorization of Maize Landraces from Aosta Valley

Abstract

While there is a rich collection of maize germplasm from Italy, it lacks genetic resources from the Aosta Valley, an isolated mountain region where landraces have been preserved in the absence of modern germplasm introductions. These local materials, which are still cultivated mainly at household level, can have high importance from a genetic and historical point of view. In the present study, five landraces named, after the collecting sites, Arnad, Arnad-Crest, Châtillon, Entrebin and Perloz, were sampled in Aosta Valley and subjected to historic, morphologic and genetic characterization. This study provided evidence for the landraces’ long presence in Aosta Valley, a significant genetic variability and differentiation among the investigated landraces. Globally, 67 different alleles were detected ranging from 4 for markers phi127 and p-bnlg176 to 10 for phi031, with a mean of 6.7 alleles per locus. Observed heterozygosity levels were comprised from 0.16 to 0.51 and are generalkly lower than expected heterozigosity supporting fixation at some loci. STRUCTURE analysis revealed clear separation between accessions revealing the presence of four ancestral populations. This may be explained by the long reproductive isolation experienced by these materials. Finally, morphological observations confirm the high diversity between landraces revealing that they generally have flint kernels, variable color from yellow to dark red (Châtillon) while Perloz showed kernels with an apical beak. The present work confirms the importance of mountain areas in conserving biodiversity and increases the rich Italian maize germplasm with materials well adapted to marginal areas. Such new genetic variability may be used to breed new materials for more resilient agriculture.

Morphological and Genetic Characterization of Maize Landraces Adapted to Marginal Hills in North-West Italy

“…Examining populations, the number of alleles varied from 30 for Va227 to 54 for both Va222 and Va223, with a mean value of 41.54 alleles. The numbers of different alleles detected in these accessions are similar to those detected in different Emilia-Romagna maize accessions previously analyzed [28,29] and in other studies conducted worldwide [11,19,20,30]. Most loci were polymorphic for all populations, except for umc1401, umc1786, and phi076 in Va226, Va227, and Va228, respectively.…”

“…The N a values recorded in this work were higher, considering other accessions from the same region previously examined by Stagnati et al [28,29], confirming the presence of good genetic diversity in the collection. The Shannon information index (I), used to characterize population diversity, had a mean value of 0.93 over all loci and populations, consistent with previous works [9,27,29,30]. The mean value of PIC over all loci was 0.54, with a minimum of 0.41 (phi084) and a maximum of 0.71 (umc1075), providing an estimation of the ability of each locus to discriminate among different genotypes [9].…”

“…The genetic characterization of the thirteen accessions was performed using ten SSR markers, which are still considered some of the best choices to analyze genetic diversity within and among populations and are widely applied for Italian maize landraces [9,25,30].…”

“…Most loci were polymorphic for all populations, except for umc1401, umc1786, and phi076 in Va226, Va227, and Va228, respectively. The presence of some monomorphic loci is common in various studies [9,13,20,[27][28][29][30] and may be the consequence of the selection by local farmers for specific characters. The high number of different alleles and level of polymorphism observed suggest a high genetic variability within populations, compatible with the allogamous nature of maize and the expected multi-genotype constitution of landraces.…”

“…Genetic characterization of maize landraces has been performed worldwide in numerous studies, using molecular markers [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Concerning Italian landraces, even if all 562 accessions were morphologically characterized for 17 traits [2,5], only few of them from northern Italy have been investigated at genetic level [7,9,[25][26][27][28][29][30].…”