Agronomic Performance of Spring Wheat Isolines Differing for Daylength Response

Abstract

Spring wheat (Triticum aestivum L.) can be either daylength sensitive or insensitive. Sensitive wheat require long days for timely flowering, whereas insensitive wheat mature normally even in short days. The objective of this study was to compare near‐isogenic daylength insensitive and sensitive hard red spring wheat lines to determine whether insensitivity had adverse effects on agronomic traits and grain protein. Eleven pairs of phenotypically diverse hard red spring wheat lines near isogenic for daylength response were evaluated in 25 environments in the upper Midwest. The grain yield for insensitive lines of all pairs was the same as or higher than for the sensitive lines, averaged over all environments. Yield differences between paired insensitive and sensitive lines varied for specific environments, but a general yield disadvantage for insensitive lines was not observed in any environment. Insensitive lines tended to outyield their sensitive counterparts in environments with lower mean yields or shorter grain fill periods. The insensitive lines were earlier in heading than the sensitive lines for most but not all pairs. Grain protein content for insensitive lines was the same as or lower than for sensitive lines, but selection of insensitive lines with adequate protein should not be difficult. The incorporation of insensitivity appears to result in genotypes generally well adapted to the upper Midwest, and may have beneficial effects on some agronomic traits.