Authors: John E Koemel Arron C Guenzi Jeffrey A Anderson Edward L Smith
Publish Date: 2004/05/27
Volume: 109, Issue: 4, Pages: 839-846
Abstract
Four major genes in wheat Triticum aestivum L with the dominant alleles designated VrnA1 VrnB1 VrnD1 and Vrn4 are known to have large effects on the vernalization response but the effects on cold hardiness are ambiguous Nearisogenic experimental lines NILs in a Triple Dirk TD genetic background with different vernalization alleles were evaluated for cold hardiness Although TD is homozygous dominant for VrnA1 formerly Vrn1 and VrnB1 formerly Vrn2 four of the lines are each homozygous dominant for a different vernalization gene and one line is homozygous recessive for all four vernalization genes Following establishment the plants were initially acclimated for 6 weeks in a growth chamber and then stressed in a low temperature freezer from which they were removed over a range of temperatures as the chamber temperature was lowered 13°C h−1 Temperatures resulting in no regrowth from 50 of the plants LT50 were determined by estimating the inflection point of the sigmoidal response curve by nonlinear regression The LT50 values were −67°C for cv TD −66°C for the VrnA1 and Vrn4 lines −81°C for the VrnD1 formerly Vrn3 line −94°C for the VrnB1 line and −117°C for the homozygous recessive winter line The LT50 of the true winter line was significantly lower than those of all the other lines Significant differences were also observed between some but not all of the lines possessing dominant vernalization alleles The presence of dominant vernalization alleles at one of the four loci studied significantly reduced cold hardiness following acclimation
Keywords: