Genetic Control of Vernalization, Day-length Response, and Earliness <em>per se</em> by Homoeologous Group-3 Chromosomes in Wheat.

To identify homoeologous group-3 chromosomes that carry genes for vernalization, day-length responses, and earliness per se, a series of aneuploid lines (mono- somics and tetrasomics) and chromosome-substitution lines in &#39;Chinese Spring&#39; (CS) were surveyed under different vernalization and day-length regimes in controlled environments. The results indicated that genes on all three chromosomes of group 3 can have striking effects on ear-emergence time, The replacement of CS 38 by its homologues in &#39;Lutescens 62&#39; and &#39;Cheyenne&#39; produced an increased Insensitivity to vernalization, while 3B homologues from &#39;Ceska Presivka&#39; gave CS a remarkable sensitivity to vernalization. This provided evidence for multiple allelism at a new Vrn locus on chromosome 3B. A negative association between gene dosage and day-length response was found an CS 3D which was thought to carry a gene for promoting insensitivity to day- length The behaviour of CS monosonic 3A and CS (Timstein 3A), in reducing numbers of days to heading independently of environmental stimuli, suggested the presence of earliness per se genes on this chromosome. [ABSTRACT FROM AUTHOR]