Identification of genetic factors influencing salt stress tolerance in white clover (Trifolium repens L.) by QTL analysis

Abstract

Allotetraploid (2n = 4x = 32) white clover (Trifolium repens L.) is the most commonly cultivated legume component of temperate pastures, sown in swards with a companion grass species. Genetic control of growth performance of white clover on saline land is highly important for dairy industries, due to increasing soil salinity problems. The objective of this study was to identify quantitative trait loci (QTLs) for salinity tolerance in terms of vegetative growth under stress. Two parental genetic maps consisting of 213 and 159 marker loci and spanning 1,973.0 and 1,837.6 cM, respectively, were constructed using simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers from a two-way pseudo-test cross F(1) population derived from pair-crossing of the Haifa(2) and LCL(2) genotypes. A total of 8 unique genomic regions on 8 linkage groups (LGs) of the Haifa(2) parental map and 6 unique regions on 5 LGs in the LCL(2) parental map were associated with plant growth under salt stress and relative growth under stress, as compared to control conditions. The results of this study indicate that salt tolerance in white clover is controlled by multiple QTLs, some at common locations, but each of limited magnitude. Location of these QTLs provides the genetic basis and potential for pyramiding of salt tolerance genes in breeding improvement.

Comparative study of seed yield and seed quality of advanced lines and commercial varieties of red clover (Trifolium pratense L.)

“…Although red clover is tolerant to wetter and lower pH soils and less favourable weather conditions than alfalfa, it is best suited where summer temperatures are moderately cool to warm and soil moisture is available throughout the growing season (Wang et al, 2010). It is grown on about 20 million hectares worldwide.…”

“…Grain yield of red clover are highly variable and range from 200 to 800 kg ha -1 , while the potential grain yield is over 1000 kg ha -1 (Vasiljevic et al, 2005). In commercial production rarely is realized 50 per cent of the potential grain yield (Wang et al, 2010).…”

Development of Genomic Resources in the Species of Trifolium L. and Its Application in Forage Legume Breeding

“…The location of the SI locus was described by Casey et al [14] and utilised a characterised BAC library for white clover with partial BAC end sequencing reported by Febrer et al [14]. Genetic maps in white clover have been reported by several groups [12,[15][16][17]. They were all based on a mixture of SSR and AFLP markers [12], or exclusively SSR markers.…”

“…Zhang et al [16] used markers transferred from red clover and M. truncatula, which allowed some analysis of synteny between the three species. Wang et al [17] used their map to identify QTL regions associated with salt tolerance. Subsequent mapping families have been constructed specifically to analyse genetic control of other key traits: stolon architecture and resistance to stem nematode (Ditylenchus dipsaci).…”

Natural antisense transcripts ofTrifolium repensdehydrins

“…Some of them were subjected to 72 h treatment with PEG (100 g PEG-6000 added to 1 L nutrient solution), and others were transferred on standard nutrient medium supplemented with 1 μM ABA 19 or 75 mM NaCl 20 and were grown for additional 14 d. Total RNA extracted from differently treated plants was reversely transcribed in sense and in antisense direction, with oligo(dT 23 ) (Sigma-Aldrich) and forward gene specific primers (Y n K n F: ATGAATATGG AAACCCAGTG and Y n SK n F: ACTGTCACCA CTCCTAATCC AACTTC), respectively. The expression of T. repens α-tubulin (GenBank ID: AY192359.1) in sense and antisense direction (Fig.…”