Evidence and consequences of self-fertilisation in the predominantly outbreeding forage legume Onobrychis viciifolia

Abstract

BackgroundSainfoin (Onobrychis viciifolia) is a promising alternative forage plant of good quality, moderate nutrient demand and a high content of polyphenolic compounds. Its poor adoption is caused by the limited availability of well performing varieties. Sainfoin is characterised as tetraploid and mainly outcrossing, but the extent of self-fertilisation and its consequences was not investigated so far. This study aimed at assessing the rate of self-fertilisation in sainfoin under different pollination regimes and at analysing the consequences on plant performance in order to assist future breeding efforts.MethodsThe self-fertilisation rate was assessed in three sainfoin populations with artificially directed pollination (ADP) and in three populations with non-directed pollination (NDP). Dominant SRAP (sequence-related amplified polymorphism) and codominant SSR (simple sequence repeats) markers were used to detect self-fertilisation in sainfoin for the first time based on molecular marker data.ResultsHigh rates of self-fertilisation of up to 64.8 % were observed for ADP populations in contrast to only up to 3.9 % for NDP populations. Self-fertilisation in ADP populations led to a reduction in plant height, plant vigour and, most severely, for seed yield.ConclusionsAlthough sainfoin is predominantly outcrossing, self-fertilisation can occur to a high degree under conditions of limited pollen availability. These results will influence future breeding efforts because precautions have to be taken when crossing breeding material. The resulting inbreeding depression can lead to reduced performance in self-fertilised offspring. Nevertheless the possibility of self-fertilisation also offers new ways for hybrid breeding based on the development of homogenous inbred lines.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-015-0275-z) contains supplementary material, which is available to authorized users.

Marker-trait association analysis for agronomic and compositional traits in sainfoin (Onobrychis viciifolia)

“…Crossings (F 1 progenies) and selfings (S 1 progenies) have previously been identified using SSR and SRAP markers (Kempf et al, 2015). The plant material was established in January 2012 by placing two sets of five clones of each parent in a greenhouse chamber for bumble bee pollinations (Bombus terrestris, "Bombus Maxi Hummeln", Andermatt Biocontrol, Switzerland).…”

“…Flowering time (FT) was recorded as the number of days after May 1st, when a plant showed three or more open flowers. Seed yield was measured as the total number of seeds per plant in 2013 (SN), as described by Kempf et al (2015).…”

“…For the SRAP marker system, four fluorescently labeled forward (me1 to me4) and reverse (em1 to em4) primers were applied in 16 combinations in all plants, while sainfoin specific primers (Mora-Ortiz et al, 2016) were used for SSR analysis (Table S1). PCR and fragment analysis were performed as described in Kempf et al (2015) using an iCycler (Bio-Rad, Hercules, CA, USA) and an ABI 3500 Genetic Analyzer (Applied Biosystems, Forster City, CA, USA). Allele counts for the SRAP markers were those used previously to analyze self-fertilization (Kempf et al, 2015), and the approach of counting alleles present in one parent and absent in the other was followed.…”

“…PCR and fragment analysis were performed as described in Kempf et al (2015) using an iCycler (Bio-Rad, Hercules, CA, USA) and an ABI 3500 Genetic Analyzer (Applied Biosystems, Forster City, CA, USA). Allele counts for the SRAP markers were those used previously to analyze self-fertilization (Kempf et al, 2015), and the approach of counting alleles present in one parent and absent in the other was followed. SSR marker data was analyzed de novo.…”

“…Marker systems that do not rely on prior DNA sequence information offer a valuable approach for the initial characterization of minor species that generally lack available sequence information. Sequence-related amplified polymorphism (SRAP), which preferentially amplify in gene rich regions (Li and Quiros, 2001), have been successfully used for the molecular investigation of allogamy and autogamy in sainfoin (Kempf et al, 2015). Recently, RNA transcriptome sequencing, using next-generation sequencing, has been successfully used to develop comprehensive simple sequence repeats (SSR) marker resources that can be applied to assess genetic diversity in sainfoin (Kempf et al, 2016;Mora-Ortiz et al, 2016).…”