Quantitative trait loci for water-use efficiency in barley (Hordeum vulgare L.) measured by carbon isotope discrimination under rain-fed conditions on the Canadian Prairies

Abstract

Barley (Hordeum vulgare L.) yield is commonly limited by low rainfall and high temperature during the growing season on the Canadian Prairies. Empirical knowledge suggests that carbon isotope discrimination (Δ(13)C), through its negative relationship with water-use efficiency (WUE), is a good index for selecting stable yielding crops in some rain-fed environments. Identification of quantitative trait loci (QTL) and linked markers for Δ(13)C will enhance its use efficiency in breeding programs. In the present study, two barley populations (W89001002003 × I60049 or W × I, six-row type, and Merit × H93174006 or M × H, two-row type), containing 200 and 127 recombinant inbred lines (RILs), were phenotyped for leaf Δ(13)C and agronomic traits under rain-fed environments in Alberta, Canada. A transgressive segregation pattern for leaf Δ(13)C was observed among RILs. The broad-sense heritability (H (2)) of leaf Δ(13)C was 0.8, and there was no significant interaction between genotype and environment for leaf Δ(13)C in the W × I RILs. A total of 12 QTL for leaf Δ(13)C were detected in the W × I RILs and 5 QTL in the M × H RILs. For the W × I RILs, a major QTL located on chromosome 3H near marker Bmag606 (9.3, 9.4 and 10.7 cM interval) was identified. This major QTL overlapped with several agronomic traits, with W89001002003 alleles favoring lower leaf Δ(13)C, increased plant height, and reduced leaf area index, grain yield, harvest index and days to maturity at this locus or loci. This major QTL and its associated marker, when validated, maybe useful in breeding programs aimed at improving WUE and yield stability of barley on the Canadian Prairies.

Genome-wide association study (GWAS) of carbon isotope ratio (δ13C) in diverse soybean [Glycine max (L.) Merr.] genotypes

“…Because of the correlation with WUE, carbon isotope composition has been analyzed in tissues from a wide range of plant species to assess WUE (Brüggemann et al 2011;Wingate et al 2010). Further, in a growing number of studies it has been used successfully to investigate the role of WUE in drought adaptation (Ahmed et al 2013;Chen et al 2012). That is, as the ratio of internal to external CO 2 decreases, both WUE and carbon isotopic composition increase.…”

Dissecting spatiotemporal biomass accumulation in barley under different water regimes using high‐throughput image analysis

“…; Chen et al . ) values. Because the expression of quantitative characters underlies strong genotype by environment (G × E) interaction, QTL accounting for minor effects may remain undetected.…”

Phenotyping for drought tolerance of crops in the genomics era

“…High genetic variation for grain Δ 13 C has been reported in C 3 species (Turner, 1997; Chen et al, 2012), with high heritability (e.g., from 0.76 to 0.85 in durum wheat; Merah et al, 2001) and a low GEI (Richards, 1996; Rebetzke et al, 2008a). For these characteristics, Δ 13 C is an attractive breeding target for improving WUE and yield, while the high cost required to measure each sample makes it an interesting candidate for MAS.…”