Validation of molecular markers associated with boron tolerance, powdery mildew resistance and salinity tolerance in field peas

Abstract

Field pea (Pisum sativum L.) is an important grain legume consumed both as human food and animal feed. However, productivity in low rainfall regions can be significantly reduced by inferior soils containing high levels of boron and/or salinity. Furthermore, powdery mildew (PM) (Erysiphe pisi) disease also causes significant yield loss in warmer regions. Breeding for tolerance to these abiotic and biotic stresses are major aims for pea breeding programs and the application of molecular markers for these traits could greatly assist in developing improved germplasm at a faster rate. The current study reports the evaluation of a near diagnostic marker, PsMlo, associated with PM resistance and boron (B) tolerance as well as linked markers associated with salinity tolerance across a diverse set of pea germplasm. The PsMlo1 marker predicted the PM and B phenotypic responses with high levels of accuracy (>80%) across a wide range of field pea genotypes, hence offers the potential to be widely adapted in pea breeding programs. In contrast, linked markers for salinity tolerance were population specific; therefore, application of these markers would be suitable to relevant crosses within the program. Our results also suggest that there are possible new sources of salt tolerance present in field pea germplasm that could be further exploited.

Discrimination of boron tolerance in Pisum sativum L. genotypes using a rapid, high-throughput hydroponic screen and precociously germinated seed grown under far-red enriched light

“…More recently, Sudheesh et al [16] identified a major QTL for B tolerance in field pea and developed a putative marker for the region that was associated with both powdery mildew (PM) resistance and B tolerance. While validating this marker across a selection of germplasm and breeding lines, Javid et al [3] confirmed a strong link between B tolerance and PM resistance (r = 0.959) but the marker incorrectly predicted B tolerance in 21% of cases. Concordant with screening results reported by Javid et al [3], we found Kaspa and Sturt to be sensitive to B.…”

“…While validating this marker across a selection of germplasm and breeding lines, Javid et al [3] confirmed a strong link between B tolerance and PM resistance (r = 0.959) but the marker incorrectly predicted B tolerance in 21% of cases. Concordant with screening results reported by Javid et al [3], we found Kaspa and Sturt to be sensitive to B. However in that study, Sturt presented the B tolerant marker.…”

“…Field pea provides benefits to cereal-based rotations as a break crop for pest and disease management and improves soil fertility from the rhizobial fixation of atmospheric nitrogen [2]. Along with improved yield, nutritional quality, adaptation and reliability, field pea breeders have identified boron (B) tolerance as an important target for improvement [3]. Boron toxicity is caused by high B concentration in soil or irrigation water, and is particularly problematic in medium or heavier textured soil types with moderate alkalinity and low annual rainfall (<500 mm p.a.)…”

“…Two non-destructive metrics available for B tolerance in field pea are molecular markers and leaf toxicity symptoms. The molecular markers currently available are not yet fully reliable [3, 16], whereas the simplicity and ease of use of leaf toxicity symptoms has led to them being the benchmark metric when screening field peas for B tolerance [3, 13, 16–18]. Regarding an ideal growth system for controlled environments, hydroponic systems allow plants to be grown compactly, which makes them suitable for use in controlled environments and enables throughput of a large number of individuals, while allowing precise and uniform exposure of plants to abiotic stresses [19–21].…”

SNP-Based Linkage Mapping for Validation of QTLs for Resistance to Ascochyta Blight in Lentil

“…SSR primer synthesis and PCR amplifications were performed as described above. SNP genotyping was performed using KASP™ genotyping chemistry (LGC, Middlesex, UK) as described in Javid et al (2015). …”