Seed Science Research

Table of Contents - 2000 - Volume 10, Issue 01  

Research Article

Dormancy in white-grain mutants of Chinese Spring wheat (Triticum aestivum L.)

R.L Warnera1 c1, D.A. Kudrnaa1, S.C. Spaetha1 and S.S. Jonesa1

a1 Department of Crop and Soil Sciences, Washington State University, Pullman, WA 99164-6420

Abstract

Red wheats (Triticum aestivum L.) are generally more dormant and sprout resistant than white wheats. Whether this is caused by pleiotropic effectsof the red grain colour genes (R) on dormancy and coat colour, or to tight linkage between R and dormancy genes has not been fully resolved. To directly determine the effect of the R1 allele on dormancy, mutations were induced with sodium azide in a pure line selection of the red genotype (R1R1r2r2r3r3) Chinese Spring wheat. Two white mutants (CSW01, CSW02) were recovered from M3 caryopses derived from approximately 20,000 M2 plants. Both mutants were shown to be allelic to a domesticwhite genotype (r1r1r2r2r3r3). Except for seed coat colour, CSW01 and CSW02 are morphologically indistinguishable from the wild type and are presumed to be near isogenic lines of Chinese Spring. Freshly harvested grainsproduced under four different environments were evaluated for post-harvest dormancy. In all environments, intact caryopses of all three isolines exhibited high temperature dormancy typical of cereal species, although the red wild type consistently exhibited greater dormancy than the white mutant isolines. Dormancy was dissipated by afterripening in dry storage at 37°C in a similar manner for the red and white isolines. Excised embryos of the three isolines exhibited similar levels of dormancy and sensitivities to exogenous abscisic acid. These results indicate a functional R1 allele is not absolutely required for dormancy in wheat, but does enhance its expression in caryopses with dormant (sensitive) embryos

(Received July 12 1999)

(Accepted November 12 1999)

Keywords

Correspondence:

c1 *Fax: (509) 335-8674 Email: rwarner@wsu.edu

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