Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/1999
Publication Date: N/A
Interpretive Summary: Wheat economic value is determined by class and kernel characteristics. Therefore, wheat breeders focus on releasing new cultivars having the physical characteristics most associated with greater profits. Their efforts are hindered because little is known about the genetic control of those characteristics and associations between them. This research project was designed to enhance our understanding of those issues. It was carried out using a wheat population well suited for examining that area because it was made from a cross between a soft and a hard wheat and it was grown during several years. DNA markers were used to find areas of the wheat genome that were associated with kernel characteristics such as length, width, area, kernel texture, 1000 kernel weight and test weight. Length and width were associated with different areas of the genome and thus seem to have been inherited independently. Kernel texture was found to be controlled by one major gene. Although associated with several areas of th genome, test weight was strongly influenced by one region. Had this knowledge been available to a breeding program, several new soft wheat lines could have been identified with significantly greater test weight, compared to the population mean.
Technical Abstract: Kernel morphological and textural traits influence the value of wheat. The objectives of this study were to determine associations between kernel traits and molecular markers and to identify QTLs affecting kernel traits in a soft x hard white wheat cross. Seventy-eight F5-derived recombinant inbred lines (RILs) from a cross between NY6432-18 and Clark's Cream were developed by single seed descent. Traits were measured through near-infrared reflectance spectroscopy (NIR). Kernel width, length, area, and perimeter were measured using digital image analysis (DIA). Test weight and thousand kernel weight were also determined. Shape factor and density factor were calculated. The molecular marker map for this population consists of 313 markers in 47 linkage groups located on all wheat homeologous chromosome groups. Linkage groups that map to wheat homeologous group 2 chromosomes were highly skewed. Transgressive segregation occurred for all traits. Genotype effects and genotype by environment interactions were highly significant for most traits. QTLs for kernel width and length also influenced kernel area and thousand kernel weight, but did not influence each other. QTLs for kernel traits were located on chromosomes 1A, 2B, 2D, 3B, 7A, and 7B. The puroB marker at the puroindoline locus, on chromosome 5DS, explained over 60 percent of the variation for kernel texture. Although the size of the mapping population is not large, we were able to detect several strong QTLs for kernel traits.