Introgression of Unadapted Germplasm into Adapted Spring Wheat1

The introgression of unadapted germplasm into adapted germplasm is one method of increasing useful genetic variability. In hard red spring wheat (Triticum aestivum L.) more information on methods of incorporation would be useful, especially for breadmaking quality traits, which are important for cuitivar release. Three populations were developed from two unadapted and three adapted wheat genotypes. The objective was to evaluate the agronomic and breadmaking quality traits of lines derived from types of crosses differing in the amount of unadapted germplasm. The four types of crosses evaluated were single cross, three‐way cross, and one and two backcrosses to the adapted parent. Twenty F2‐derived lines from each type of cross for each population were evaluated in three field environments. Although the means of the types of crosses did not differ significantly for yield, the mean of lines derived from the single cross were generally lowest and this cross produced the fewest high yielding lines and fewest lines with both high yield and good breadmaking potential. The first backcross and the three‐way cross produced similar numbers of high yielding lines. The second backcross produced no more high yielding lines than the first backcross or three‐way cross and required an additional generation to develop. Means of types of crosses for quality traits tended to approximate the mean of the parent contributing the largest percentage of germplasm to the cross. Genetic variation for grain yield and wheat protein concentration were similar for most types of crosses, except BC2, which had less variation. The relative proportions of the higher performing parent appeared as important as the type of cross used for development of lines.