Characterizing the molecular and morphophysiological diversity of Italian red clover

Abstract

Red clover (Trifolium pratense L.) is the third major forage species in Europe, but there is limited information on the biodiversity and the genetic structure of landraces and natural populations which evolved in this region. The objective of this study was producing such information for Italian germplasm on the ground of molecular and morphophysiological diversity. The study included 16 Italian natural populations from a wide range of environments, four landraces representing the four traditional commercial ecotypes, and two varieties. Eight morphophysiological traits were assessed in a replicated trial under field conditions, whereas two AFLPs primer combinations with 140 polymorphic markers were recorded on a random sample of 13 genotypes per population. Ordination and classification results based on morphophysiological data clearly kept track of the type of germplasm (i.e. landrace or natural population) and its geographic origin, unlike results based on molecular markers. Euclidean distances among populations based on morphophysiological traits were not correlated with Nei's genetic distances based on molecular markers according to Mantel's test. Geographical distances among landrace or natural population material was correlated with distances based on morphophysiological traits but not with those based on molecular markers. The average within-population variation estimated via molecular markers was about 2.6-fold higher than that among populations, preventing an acceptable discrimination among most populations. On average, natural populations tended to have within-population variation similar to varieties and somewhat lower than landraces. Our results have implications for collection, conservation, exploitation and registration in a sui generis system of red clover genetic resources.

Origin of Ladino White Clover as Inferred from Patterns of Molecular and Morphophysiological Diversity

“…The substantial inconsistency between morphophysiological and molecular diversity agrees with earlier reports for white clover (Kölliker et al, 2001) and other perennial forage legumes (Crochemore et al, 1998;Greene et al, 2004;Pagnotta et al, 2011). Ladino landrace and wild population germplasm displayed only moderate morphophysiological similarity, whereas Ladino material as a whole was only somewhat more similar to TRP042 and TRP046 than to the Fries-Groninger landrace.…”

Achievements and Challenges in Improving Temperate Perennial Forage Legumes

“…The latter aim has great practical importance for establishing core collections or choosing subsets of populations for evaluation activities, but requires fairly good consistency between molecular and morphophysiological information. Results from various studies, e.g., Greene et al (2004) and Pagnotta et al (2011) for red clover, Crochemore et al (1998) for alfalfa, and Kölliker et al (2001b) for white clover, substantially challenge this assumption -although more conclusive results are awaited from studies based on high numbers of markers (such as those allowed for by next-generation sequencing techniques). Information is lacking on the ability of molecular studies to predict the level of intra-population Downloaded by [West Virginia University] at 06:45 20 November 2014 morphophysiological diversity featuring different populations, or to predict combining ability among populations.…”

“…For example, the diversity of diploid alfalfa germplasm has been recently elucidated using SSR markers (Ş akiroglu et al, 2010), which could help identify desirable phenotypes that have different marker profiles (Ş akiroglu et al, 2011). Marker-based diversity among germplasm sources may only limitedly infer their morphophysiological diversity, based on reports relative to red clover (Dias et al, 2008;Pagnotta et al, 2011) and white clover (Kölliker et al, 2001b;Annicchiarico and Carelli, 2014).…”

Agronomic value and adaptation across climatically contrasting environments ofItalian red clover landraces and natural populations

“…Swiss natural populations proved more prostrate, more persistent and less vigorous than landraces or varieties (Nüesch, ; Simon, ), as well as sharply distinct from landraces on a molecular basis (Herrmann et al ., ). The molecular distinctness from landrace germplasm was less clear‐cut for natural populations from Italy, which also featured large genetic diversity between geographically distant materials (Pagnotta et al ., ). European red clover breeding has mainly exploited landrace genetic resources (Boller et al ., ).…”