Page Banner

United States Department of Agriculture

Agricultural Research Service


item Dilbirligi, Muharrem
item Erayman, Mustafa
item Campbell, Benjamin - Todd
item Randhawa, Harpinder
item Baenziger, P.
item Dweikat, Ismail
item Gill, Kulvinder

Submitted to: Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2005
Publication Date: 4/19/2006
Citation: Dilbirligi, M., Erayman, M., Campbell, B.T., Randhawa, H.S., Baenziger, P.S., Dweikat, I., Gill, K.S. 2006. High-density mapping and comparative analysis of agronomically important traits on wheat chromosome 3A. Genomics 88:74-87.

Interpretive Summary: Bread wheat is one of the most important agricultural crops in the United States and worldwide. Increased productivity of bread wheat (producing more on less land) can be accomplished through genetic research focused on identifying the genes controlling grain yield and grain yield related traits. Once identified, intensive study of these genes will help scientists better understand the biological processes involved to facilitate development of new varieties with increased productivity. Identifying genes controlling important traits can be aided by exploring comparative genetics among different plant families and species. Comparative genetics has revealed that bread wheat shares genetic similarity to rice and other cereals in the Poaceae family; these similarities allow for bread wheat researchers to capitalize on knowledge gained from related crop plants (e.g., rice) to study specific genetic issues in bread wheat. In this study, quantitative trait loci (QTLs) or genes controlling grain yield and yield component traits were genetically and physically mapped to specific regions of bread wheat chromosome 3A which corresponded to only 13% of the entire 3A chromosome. Comparative DNA sequence analysis revealed 76% of the wheat chromosome 3A sequences were also present in the rice genome. Of these similar sequences, 48% corresponded to variable sized segments on the rice chromosomes, with the remaining 52% localizing to rice chromosome 1. Knowledge gained from this study will aid future efforts to 1) isolate and clone the wheat chromosome 3A yield and yield component QTLs mapped in this study, and 2) further explore gene similarities among wheat, rice, and other cereals.

Technical Abstract: Bread wheat chromosome 3A has been shown to contain genes/QTLs controlling grain yield and its component traits. The objectives of this study were to generate high-density physical and genetic linkage maps of wheat homoeologous group 3 chromosomes, reveal the physical location of genes/QTLs controlling agronomic traits, obtain a precise estimate of recombination for the corresponding regions, and enrich the QTL-containing regions with markers. Physical mapping was accomplished by mapping 179 DNA markers mostly representing expressed genes on 41 single-break deletion lines. Polymorphism survey of cultivars Cheyenne (CNN) and Wichita (WI), and a substitution line of CNN carrying chromosome 3A from WI {(CNN(WI3A)}, with 152 RFLP probes and 55 SSR markers revealed that the extent of polymorphism is different among various group 3 chromosomal regions as well as among the three homoeologues. A genetic linkage map for chromosome 3A was developed by mapping 17 QTLs for seven agronomic traits relative to 26 RFLP and 15 SSR DNA markers on 95 single-chromosome recombinant inbred lines. Comparison of the physical maps with the genetic linkage map localized these QTLs to eight regions that accounted for only about 13% of the chromosome. Two chromosomal regions that contained nine of these QTLs, encompassed less than 10% of the chromosome but accounted for almost all of the short arm recombination. In order to identify rice chromosomal regions corresponding to the QTL-containing wheat regions, 650 physically mapped wheat group 3 DNA sequences were compared with the rice genomic sequences. At E=10**-5, 76% of the wheat sequences identified rice homologs, of which 52% were on rice 1. The remaining homologs were on the other 11 rice chromosomes as blocks of varying sizes identified by one to six wheat sequences. Rice chromosome 1 regions corresponding to the two wheat regions containing nine QTLs was about 6.5 Mb.

Last Modified: 10/16/2017
Footer Content Back to Top of Page