Genetic control of pre-heading phases in the Steptoe × Morex barley population under different conditions of photoperiod and temperature

Abstract

Although there are numerous studies on the genetic control of flowering time in barley, little is known on the genetic control of duration of different particular pre-heading phases. Extending the stem elongation phase (SE), without modifying total time to heading, has been proposed as a trait to raise yield potential. Moreover, studying the genetic control of pre-heading phases would be of interest for a better understanding of crop phenology which is crucial for adaptation. We studied the genetic control of the leaf and spikelet intitiation phase (LS), the stem elongation phase, and within this, from the onset of jointing to flag leaf (J-FL), and from then to heading (FL-HD), in the Steptoe 9 Morex population, which is known to segregate for some major developmental genes, under different environmental conditions. After a preliminary greenhouse study in which the appropriateness of the population was tested, 130 double haploid lines and the two parents were grown under four field environments that differed in photoperiod and temperature conditions. Amongst all QTLs detected (13), only three were significant for HD and for both LS and SE and with the same allele direction (although with greater effects in one phase than the other in some cases). Genotype by environment interactions for LS and HD were due to both photoperiod and other factors as temperature or its interaction with photoperiod, while for SE responses to only photoperiod were negligible. QTL 9 E interactions were important for some QTLs, and either cross-over (e.g. Ppd-H1) or quantitative (e.g. Ppd-H2). However, heritability across field environments for the ratio SE/LS was high (0.8) and several of the QTL effects that were significant for only LS or SE, were conserved across different environments, that is, they were significant with the increasing allele derived from the same parent in all or most environments.

Quantitative trait loci for agronomic traits in an elite barley population for Mediterranean conditions

“…Both Comadran et al (2011) and Wang et al (2012) identified a heading date QTL in this region in two different association panels. This region was reported by Borrás-Gelonch et al (2012) as having a very large effect on days to heading and on the duration of developmental phases of barley, and was highlighted by Cuesta-Marcos et al (2008a,b) as the one having the main earliness QTL for Mediterranean environments, co-locating with the gene Eam6. The effect of this gene has been linked to variations in the minimum temperatures during the heading phase (van Eeuwijk et al 2010).…”

Estimation of epistasis in doubled haploid barley populations considering interactions between all possible marker pairs

“…Epistasis as an important genetic basis of complex phenotypes has also been revealed in several recent QTL mapping studies Yu et al 1997;Ma et al 2005;Liu et al 2011;Rahman et al 2011;Borràs-Gelonch et al 2012;Krajewski et al 2012). However, marker-based analyses for estimation of QTL effects usually assume the absence of epistasis among QTLs (Lander and Botstein 1989;Jansen 1993;Zeng 1994;Bocianowski and Krajewski 2009;Rovaris et al 2011).…”

QTLs for earliness and yield-forming traits in the Lubuski × CamB barley RIL population under various water regimes

“…SNP 11_21015 has been mapped close to markers 12_30871 and 12_30872 (Muñoz-Amatriaín et al 2011) which are SNPs in Ppd-H1 . Borrás-Gelonch et al (2012), following a series of experiments involving environments with artificially extended photoperiod, reported the two QTLs affected earliness on chromosome 2H. The regions on 2H were also the main determinants of heading date in autumn-sown experiments conducted using mapping populations grown under Mediterranean conditions (Moralejo et al 2004; Cuesta-Marcos et al 2008).…”