Cold hardiness of wheat near-isogenic lines differing in vernalization alleles

• Published in: Theoretical and applied genetics 2004-08, Vol.109 (4), p.839-846
• Main Authors: Koemel, J.E. Jr, Guenzi, A.C, Anderson, J.A, Smith, E.L
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Alleles; Biological and medical sciences; Classical genetics, quantitative genetics, hybrids; Cold; Cold Temperature; cold tolerance; Crosses, Genetic; days to spike emergence; dominance (genetics); dominant alleles; flowering; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; isogenic lines; loci; major genes; plant development; Pteridophyta, spermatophyta; Regression Analysis; Seasons; Species Specificity; Time Factors; Triticum - genetics; Triticum - growth & development; Triticum aestivum; Vegetals; vernalization; wheat
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-004-1686-9

Four major genes in wheat (Triticum aestivum L.), with the dominant alleles designated Vrn-A1, Vrn-B1, Vrn-D1, and Vrn4, are known to have large effects on the vernalization response, but the effects on cold hardiness are ambiguous. Near-isogenic 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 Vrn-A1 (formerly Vrn1) and Vrn-B1 (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 1.3°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 -6.7°C for cv. TD, -6.6°C for the Vrn-A1 and Vrn4 lines, -8.1°C for the Vrn-D1 (formerly Vrn3) line, -9.4°C for the Vrn-B1 line, and -11.7°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.