ALBERT

Description: SUMMARYIn order to reduce the environmental impact of agriculture and improve the resilience and sustainability of our food systems, there is an increasing interest in shifting from the present agricultural systems, which are characterized by high external inputs, to low-input productive systems characterized by high resilience and sustainability. Purposely developed varieties are needed for the latter. With the rapid disappearance of landraces, heterogeneous populations such as composite cross populations (CCPs) or line mixtures, developed through evolutionary plant breeding, could be the ideal source of breeding material for the development of new cultivars for low-input productive systems. Parental lines of CCPs should be selected among old breeding lines, varieties or landraces because the specific characteristics required for low-input or organic farming systems might have been lost during selection of modern varieties. In the current scenario of renewed interest in evolutionary plant breeding, the evolution of diversity in heterogeneous populations needs to be better investigated to maximize the advantages that can be obtained by their utilization.The present paper reports on the analysis of 88 barley plants chosen randomly from a CCP, namely AUT DBA (where AUT indicates autumn sowing and DBA is the acronym of the former Department) that was multiplied for 13 years under a low-input management system without any conscious human selection, aiming to investigate the morphological diversity still existing in the population and its potential value as source of breeding material for low-input/organic agriculture and understanding the traits that contributed to the adaptive success of certain groups of individuals.Eighteen plant and spike morphological traits were analysed using bi-dimensional spatial analysis, cluster analysis, non-parametric tests and multivariate approaches. Low lodging and loose smut damage were observed in the CCP where several individuals were superior to the best control for at least one of the four yield-related traits, namely spike weight, number of seeds per spike, weight of seeds in a spike and grain weight. Three morphological clusters were identified using cluster analysis. Clusters 2 and 3 grouped the largest number of CCP individuals which, compared with those in cluster 1, were characterized mainly by heavier spikes with higher seed number, taller culms and early flowering. Interestingly, the plant architecture of all the controls was different from that of the most frequent genotypes in the CCP, showing that low-input systems may require a plant architecture different from the one usually considered as the most suitable for high-input systems. Taking advantage of results from Raggi et al. (2015), phenotypic data were also analysed according to individual genetic group assignment. Results suggest that plant height at the beginning of stem elongation, and days to heading, together with traits related to culm and leaf morphology, could have played a significant role in determining the success of plants from genetic group D, which is the group most represented in the CCP.According to the wide range of morphological diversity existing in the AUT DBA and the high percentage of lines that show favourable combinations of different traits, this population could be a useful gene-pool from which to select lines for breeding activities. Even though further use of the CCP for breeding purposes may be limited by its possible evolution, there are different ways of manipulating the CCP to counteract the undesirable changes without great economic and/or technical efforts. The high number of multi-locus genotypes and the evolutionary responses observed in AUT DBA show that the prediction that phenotypic micro-evolution in natural systems may be limited by low genetic variances in harsh environments and low selection pressure in good environments is not necessarily true for low-input systems.

Description: SUMMARYMany studies have highlighted the continuously increasing need for genetic diversity in the field; nonetheless, plant breeding is still predominantly generating uniform cultivars. Evolutionary plant breeding offers the possibility of reconciling agro-biodiversity, high yields and adaptation to climate change. However, the diversity that can be conserved in heterogeneous populations, its evolution and the potential of ‘evolutionary breeding’ in the actual scenario of climate change is still a matter of debate. In the present study, a total of 147 barley individuals, 56 from seven parental populations (PPs) and 91 from the composite cross-derived population (CCP) resulting from their inter-crossing were genotyped at 22 Simple Sequence Repeat (SSR) loci with the objective of obtaining insights into how genetic diversity evolved in the field during 13 years of multiplication. A total of 92 different alleles were detected in the PP and 100 in the CCP. Results showed that the composite individuals are grouped into five major clusters differing for both the number of individuals and the relative level of genetic diversity. The mean values of the most common descriptors of genetic diversity were not significantly different between the parental and the composite populations. However, analysis of molecular variance showed some degree of differentiation between the two populations suggesting that evolution occurred during the years of multiplication and selection effects were detected for some loci. The SSR loci detected as putatively under selection in the present study have already been reported as co-localized with quantitative trait loci for adaptedness traits or tagging genes related to abiotic stress response. According to the current results, evolving crop populations, which have the capability of adapting to the conditions under which they are grown, can be useful in conserving genetic diversity and as sources of genes for breeding purposes in particular in the actual scenario of climate change.

Description: In the actual climate change scenario, in situ conservation of plant genetic resources for food and agriculture can significantly contribute broadening the diversity of our food system as well as increasing its resilience; nevertheless, landrace cultivation has been dramatically reduced in the last decades all over Europe. One of the most effective approaches to counteract the loss of landrace diversity in situ is facilitating its use. Aims of this study were to (i) describe how in situ maintenance of landraces occurs in different agro-environmental conditions in Europe and (ii) identify the main factors influencing landrace added values and accessibility as means to increase their adoption by new farmers. To the purpose, a collection of 95 case studies of both garden and open field landraces maintained in situ was analysed. A first description was obtained by classifying the information into 18 purposely defined categories. Data on landraces added values and accessibility were further transformed into weighted variables; the derived quantitative scores were then used as dependent variables in univariate and multivariate analyses. Results showed that farmers alone are still the main actors maintaining landraces in situ across different European biogeographical regions, mainly carrying out their activity under organic or low-input conditions, often in marginal areas. Results of the multivariate analysis showed that (i) type of actor involved in the multiplication, (ii) the main use of the product and (iii) presence of promotion actions significantly affect garden landraces added value and accessibility; presence of promotion actions was the only factor affecting added value of open field entries. Evidence arising from this work can contribute to the establishment of a fruitful ground of discussion for future European policies and strategies to protect and increase landrace use.