EXPRESSION OF VERNALIZATION GENES IN NEAR-ISOGENIC WHEAT LINES: METHODS OF VERNALIZATION

Abstract

Four near isogenic lines of wheat (Triticum aestivum L. em Thell.) were given various combinations of vernalization as imbibed seed and as growing plants. The combinations were designed so that all treatments had the equivalent of four weeks at 4 °C. In terms of days to anthesis the lines reacted in three different ways to increases in the proportion of the vernalization treatment given to the growing plant. Two lines exhibited a threshold response, another showed a graded response, while the remaining line was unaffected by the method of vernalization. The treatments affected final leaf number differently, and the usually strong positive correlation with days to anthesis was not evident. Similarly there was no evidence of a relationship between days to anthesis and spikelet number. The rate of reproductive development of varieties vernalized as imbibed seed will not necessarily reflect their development rate when vernalized naturally in the field. Hence wheat breeders adapting varieties to particular environments by the use of vernalization genes should evaluate their action under appropriate field conditions.