Harnessing Novel Diversity From Landraces to Improve an Elite Barley Variety

Abstract

The Spanish Barley Core Collection (SBCC) is a source of genetic variability of potential interest for breeding, particularly for adaptation to Mediterranean environments. Two backcross populations (BC 2 F 5 ) were developed using the elite cultivar Cierzo as the recurrent parent. The donor parents, namely SBCC042 and SBCC073, were selected from the SBCC lines due to their outstanding yield in drought environments. Flowering time, yield and drought-related traits were evaluated in two field trials in Zaragoza (Spain) during the 2014–15 and 2015–16 seasons and validated in the 2017–18 season. Two hundred sixty-four lines of each population were genotyped with the Barley Illumina iSelect 50k SNP chip. Genetic maps for each population were generated. The map for SBCC042 × Cierzo contains 12,893 SNPs distributed in 9 linkage groups. The map for SBCC073 × Cierzo includes 12,026 SNPs in 7 linkage groups. Both populations shared two QTL hotspots. There are QTLs for flowering time, thousand-kernel weight (TKW), and hectoliter weight on a segment of 23 Mb at ~515 Mb on chromosome 1H, which encompasses the HvFT3 gene. In both populations, flowering was accelerated by the landrace allele, which also increased the TKW. In the same region, better soil coverage was contributed by SBCC042 but coincident with a lower hectoliter weight. The second large hotspot was on chromosome 6H and contained QTLs with wide intervals for grain yield, plant height and TKW. Landrace alleles contributed to increased plant height and TKW and reduced grain yield. Only SBCC042 contributed favorable alleles for “green area,” with three significant QTLs that increased ground coverage after winter, which might be exploited as an adaptive trait of this landrace. Some genes of interest found in or very close to the peaks of the QTLs are highlighted. Strategies to deploy the QTLs found for breeding and pre-breeding are proposed.

Development of a Multipurpose Core Collection of Bread Wheat Based on High-Throughput Genotyping Data

“…The Vrn-A1 gene is one of the most determinant loci involved in the transition from vegetative to reproductive growth [63], and thus for wheat adaptability. Such adaptation of Spanish landraces to different agroecological conditions has resulted in the accumulation of favorable alleles, including for stress tolerance, which can be incorporated into breeding programs [44,[64][65][66]. Furthermore, in the case of wheat, functional quality requirements must also be kept in mind in order to have a multipurpose collection useful for wheat improvement.…”

Effects of Low Water Availability on Root Placement and Shoot Development in Landraces and Modern Barley Cultivars

“…These strategies should be explored further. Actually, several populations were developed from crosses between SBCC073 or SBCC042, with cultivar Cierzo, and SBCC073 with cultivar Orria [15,58], and are amenable for future studies. The results of the present experiment led us to propose making a new population from the cross between SBCC073 and SBCC146, to test rooting features and shoot-root dynamics between these genotypes with contrasting partitioning features.…”

“…Therefore, our results should be validated at a later stage. In this respect, partial validation is provided by the high intrinsic SPAD values for genotype SBCC073 in a biparental mapping population, in which two QTLs for this trait were found [58].…”

Introgression Breeding in Barley: Perspectives and Case Studies

“…Land races are often described as reservoirs of useful genetic variation for barley improvement and have been used for that purposed (Monteagudo et al, 2019). Historically, land races were a key resource for introgressing alleles into pure line varieties -an example is the Rpg1 allele tracing to the landrace "Chevron" that subsequently protected North American barley from stem rust (incited by Puccinia graminus f.sp.…”

“…The latter contains 29,870 barley accessions including cultivars, breeding lines, land races, wild relatives and genetic stock from more than 100 countries (Bockelman and Valkoun, 2011) and has been extensively characterized for a range of economically important traits (Dahleen et al, 2012;Muñoz-Amatriaín et al, 2014a;Hemshrot et al, 2019). These collections, and others like them, are a rich source of germplasm for finding novel alleles for disease resistance (Czembor, 2000;Yun et al, 2006) drought tolerance (Talamé et al, 2004;Monteagudo et al, 2019) cold tolerance (Visioni et al, 2013;TCAP, 2014) yield (Nice et al, 2019) and other critical traits. One specific example of the effective use of the United States collection is introgressing resistance to the Russian Wheat Aphid (Diuraphis noxia).…”