RFLP mapping of five major genes and eight quantitative trait loci controlling flowering time in a winter × spring barley (Hordeum vulgareL.) cross

Abstract

A genetic map of 92 RFLP loci and two storage protein loci was made using 94 doubled-haploid lines from a cross between the winter barley variety Igri and the spring variety Triumph. The markers were combined with data from two field experiments (one spring sown and one autumn (fall) sown) and a glasshouse experiment to locate a total of 13 genes (five major genes and eight quantitative trait loci (QTL)) controlling flowering time. Two photoperiod response genes were found; Ppd-H1 on chromosome 2(2H)S regulated flowering time under long days, while Ppd-H2 on chromosome 5(1H)L was detected only under short days. In the field experiments Ppd-H1 strongly affected flowering time from spring and autumn sowings, while Ppd-H2 was detected only in the autumn sowing. The glasshouse experiment also located two vernalization response genes, probably Sh and Sh2, on chromosomes 4(4H)L and 7(5H)L, respectively. The vernalization response genes had little effect on flowering time in the field. Variation in flowering time was also affected by nine additional genes, whose effects were not specifically dependent on photoperiod or vernalization. One was the denso dwarfing gene on chromosome 3(3H)L. The remaining eight were QTLs of smaller effect. One was located on chromosome 2(2H), one on 3(3H), one on 4(4H), one on 7(5H), two on 6(6H), and two on 1(7H). Model fitting showed that the 13 putative genes, and their interactions, could account for all the observed genetical variation from both spring and autumn sowings, giving a complete model for the control of flowering time in this cross.

AB-QTL analysis in spring barley: II. Detection of favourable exotic alleles for agronomic traits introgressed from wild barley (H. vulgare ssp. spontaneum)

“…The QTL QHea.S42-2H.a, explaining 17.4% of the genetic variance, coincides with the major flowering QTL on chromosome arm 2HS detected by Pillen et al (2003) and Li et al (2004). The same region harbours the photoperiod response gene Ppd-H1, which promotes early flowering under long day conditions (Laurie et al 1995). The QTLs QHea.S42-1H.a and QHea.S42-4H.a mapped to the same location as the vernalisation response genes Vrn-H3 and Vrn-H2 on chromosomes 1H and 4H, respectively (Laurie et al 1995).…”

“…The same region harbours the photoperiod response gene Ppd-H1, which promotes early flowering under long day conditions (Laurie et al 1995). The QTLs QHea.S42-1H.a and QHea.S42-4H.a mapped to the same location as the vernalisation response genes Vrn-H3 and Vrn-H2 on chromosomes 1H and 4H, respectively (Laurie et al 1995). It is interesting to note, that at these two QTLs, which coincide with known vernalisation response genes, the elite alleles reduced time to heading compared to the exotic alleles.…”

“…Although vernalisation response is commonly displayed by winter forms of cereals, our data indicate, that vernalisation response may have also been selected in German spring barley cultivars as an adaptation to low temperatures at the beginning of the vegetation period. The QTL QHea.S42-3H.b mapped close to the denso gene, which is known to be associated with a delay in flowering time (Barua et al 1993;Laurie et al 1995). The elite parent Scarlett carries the denso gene and as such contributed the allele, which delayed time to heading.…”

“…The elite parent Scarlett carries the denso gene and as such contributed the allele, which delayed time to heading. Laurie et al (1995) mapped a number of flowering QTLs termed earliness per se (eps) QTLs, which act independently from environmental cues. In S42, three QTLs on chromosomes 6H and 7H could be identified which correspond to the genes eps6L.1, eps7S and eps7L (see Table 3).…”

Detection of photoperiod responsive and non-responsive flowering time QTL in barley

“…Photoperiod also plays an important role in determining winter hardiness (Hayes et al 1997, Szucs et al 2006, Takahashi and Yasuda 1970. The photoperiod response gene Ppd-H1, located on chromosome arm 2HS, regulates flowering time under long days, while Ppd-H2 on chromosome arm 1HL functions only under short days (Laurie et al 1995). Ppd-H1 encodes a pseudo-response regulator (PRR) (Turner et al 2005), which is different from the major photoperiod response genes Hd1 and Hd3a in rice (Kojima et al 2002, Yano et al 2000.…”