Chromosomal Locations of Genes for Traits Associated with Lodging in Winter Wheat

Lodging in wheat (Triticum aestivum L.) is a complex character which is influenced by morphological traits as well as environmental conditions. Wheat breeding programs would benefit from cytogenetic information on lodging and associated traits. Reciprocal substitutions between the hard red winter wheats, ‘Wichita’ and ‘Cheyenne’, for all chromosomes except Cheyenne 2B in Wichita were used to investigate additive and interactive effects of individual chromosomes on nine traits previously reported to be associated with lodging. Duplicate lines for each chromosome except Cheyenne 3B in Wichita were included to check background homogeneity. Straw strengths were measured by using an Instron universal testing machine (Instron Ltd., Canton, Ma) to break basal internodes of main tillers from plants grown in a field on a Sharpsburg silty-clay loam soil (fine, montmorillonitic, mesic Typic Argiudolls) at Lincoln, NE, with a randomized complete block design. Data on the other eight traits (height, length and diameter of basal internodes, number and width of inner vascular bundles, width of culm wall, diameter of culm cavity, and width of tissue from epidermis through sclerenchyma layer) were collected from main tillers of a greenhouse planting with an augmented randomized complete block design. Wichita and Cheyenne differed significantly only in plant height and basal-internode length among the nine traits. Substitutions of Cheyenne chromosomes into Wichita produced almost three times as many significant phenotypic changes as substitutions of Wichita chromosomes into Cheyenne. Reciprocal effects were obtained for chromosomes 3B (number of vascular bundles and culm-wail width) and 3D (basal-internode diameter). Each of the three Cheyenne homoeologous Group 4 chromosome pairs increased the number of vascular bundles in Wichita. Cheyenne chromosomes 3B and 6A each produced favorable effects in Wichita on several traits related to lodging resistance. Other Cheyenne chromosomes with major effects on single traits in Wichita were 5D for straw strength, 7A for plant height, and 2A for number of vascular bundles. The use of reciprocal substitution lines revealed reciprocal effects of homologues as well as interactions between substituted chromosomes and specific genetic backgrounds. Part of a thesis submitted by the senior author in partial fulfillment of the requirements of the M.S. degree. Research was conducted under project 12-034 and USDA Competitive Res. Grant no. 82-CRCR-1-1015.