The influence of flowering time genes on environmental adaptability in European wheats

Abstract

In order to obtain high levels of environmental adaptability in wheat varieties it is essential they flower at times appropriate to particular environmental conditions. The influence of three distinct genetic systems that together determine time of flowering is reviewed here.Vernalization genes are seen to be particularly important to winter wheats for their direct or indirect effects on winter hardiness. Vernalization genes play a minor role in determining flowering time in autumn sown winter wheats but insensitivity is essential if spring sown wheats are to flower.Day length sensitive photoperiod genes play a major role in determining flowering time and adaptability of autumn sown wheats. Insensitivity can promote yield advantages of over 35% in Southern European environments, 15% in Central Europe and offers benefits even in the UK. At present only a single allele of Ppdl appears to have been introduced into commercial European wheat varieties. The merits of alternative Ppdl alleles or different loci are discussed.The influence of earliness per se genes that determine flowering time independently of environmental stimuli is less well documented than the effect of photoperiod and vernalization genes. It is likely that genes on chromosomes belonging to groups 2, 3, 4, 6 and 7 may act to modify flowering time independently of environmental stimuli probably by determining numbers of vegetative and floral primordia being initiated or the rate of initiation of the primordia. Earliness per se genes appear to be widespread in European wheats and play a significant role in determining the exact time plants flower.

Segregation analysis of heading traits in hexaploid wheat utilizing recombinant inbred lines

“…One is located close to the Ppd-B1 locus while the other is in the Xabc451-Xpsr102b interval. The latter is possibly the same as the one reported by Worland (1996), owing to the position near the centromere on RFLP maps. In barley, eps2S, located near the centromere region of the 2H chromosome, has been reported to be a QTL for narrow-sense earliness (Laurie et al, 1995).…”

Association Analysis of Historical Bread Wheat Germplasm Using Additive Genetic Covariance of Relatives and Population Structure

“…Another point worth mentioning is that since markers represent attributes of lines, an appropriate model would include lines nested within markers (Malosetti et al 2007) and within subpopulations. When markers are explicitly included in LMM1 and LMM2 as fixed (or random) effects, it is not clear how the effect of relationship matrix A (or Other loci associated with grain yield in wheat are Eps (earliness per se) (Worland 1996;Van Beem et al 2005), Ppd (photoperiod insensitivity) (Worland 1996;Worland et al 1998;Van Beem et al 2005), Rht (semidwarf plant height) Ellis et al 2002), and Vrn (vernalization) (Worland 1996;Barret et al 2002;Yan et al 2003;Van Beem et al 2005).…”

Management of crop water under drought: a review

“…Shortening of flowering time (e.g. Worland 1996;Campos et al 2004), inhibited pollination or seed abortion leading to reduced kernel number per ear/pod (e.g. Herrero and Johnson 1981;Ekanayake et al 1989;Gan et al 2004), as well as low single grain weight due to bad grain filling significantly reduce the sink capacity of grains and impair overall crop yield (e.g.…”