Linkages between wheat development and growth: it’s in the genes

Felicity Harris1,2, Howard Eagles4,5, James Virgona1,6, Peter Martin1,3,7, Jason Condon1 and John Angus1,4

1EH Graham Centre, Charles Sturt University, Wagga Wagga, NSW 2650,  Australia

2Current address, 3former address: Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia Email: felicity.harris@dpi.nsw.gov.au

4CSIRO Agriculture and Food, Black Mountain Science and Innovation Park, GPO Box 1700, Canberra, ACT 2601, Australia

5Mailing address: 3 Tacoma Boulevard, Pasadena, SA 5042, Australia

6Current address: Graminus Consulting, 1 Heron Place, Wagga Wagga, NSW 2650, Australia

7Current address: Howqua Consulting, 48 Fulham Road, Alphington, VIC 3078, Australia

Abstract

There has been some anecdotal evidence that suggests rate of development and the accumulation of biomass may be associated, with reports early-maturing cultivars grow faster than later-maturing cultivars. Rate of development is largely determined by responses to photoperiod and vernalisation controlled by the PPD1 and VRN1 genes. PPD1 and VRN1, are now known to be regulatory genes, influencing traits in addition to phenology, though effects on crop growth have not previously been reported in field crops. The effects of Ppd-B1, Ppd-D1, Vrn-A1, Vrn-B1 and Vrn-D1 genes on anthesis date and crop growth rate were measured on forty-seven lines from a doubled-haploid population derived from the cross between cv. Janz and cv. Diamondbird. The lines were grown in replicated field experiments at Wagga Wagga and Yanco in 2010. These genes accounted for 75% of the genetic variance in anthesis date. Presence of the winter allele at either Vrn-A1 or Vrn-B1 delayed anthesis, whilst genotypes with winter alleles at all three VRN1 loci (Vrn-A1v + Vrn-B1v +Vrn-D1v) caused the largest delay in anthesis date and were classified as winter types. Presence of the winter allele Vrn-B1v consistently reduced biomass and slowed crop growth rate compared to the spring allele Vrn-B1a. However, the suppression of growth reported for Vrn-B1v was independent of alleles at other VRN1 loci, suggesting the effect of VRN1 genes on plant growth is a pleiotropic effect of these genes, rather than a direct association with development per se. The faster growth associated with Vrn-B1a may explain the yield advantage of cultivars with this allele in some environments reported in a previous study.

Host

The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

Photo Credits

David Marland Photography david_marland@hotmail.com Southern Farming Systems Agriculture Victoria

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