Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2004
Publication Date: 2/7/2005
Citation: Foley, M.E., Gu, X., Kianian, S. 2005. Seed dormancy and other weedy characteristics are interrelated. Weed Science Society of America. [Abstract]. Page No. 51. Interpretive Summary: Seed dormancy is an important adaptive trait for the persistence of weeds. We are using weedy rice as a model system to investigate seed dormancy and pre-harvest sprouting. We screened a number of weedy strains and domesticated cultivars of rice for the type and depth of dormancy. Then, selected weedy strains were crossed and backcrossed to a non-dormant rice breeding line for genetic analysis of the relationship between dormancy and the seed shattering, awn, hull color, and pericarp/testa color characteristics. We discovered that all these characteristics are interrelated and the weedy form of the trait tends to reduce germination, that is, increase covering-imposed seed dormancy. The interrelationship among these characteristics suggests they are an adaptation for the persistence and survival of weeds.
Technical Abstract: Seed dormancy is a major adaptive trait in weedy plants. We investigated the relationship between seed dormancy and other weedy characteristics, i.e., shattering, awn, black hull color, and red pericarp color, in weedy rice (Oryza sativa). Initially, three dormant weedy strains LD, TKN12-2, and SS18-2 were crossed and backcrossed (BC1F1) with the non-dormant breeding line EM93-1. Using these populations, we determined that seed covering-imposed dormancy and the shattering, awn, black hull color, and red pericarp color characteristics interrelated; the weedy forms of the characteristics significantly reduced germination. Multiple linear regression analyses revealed significant interaction effects between the characteristics on dormancy in the populations. Next, we used the EM93-1//EM93-1/SS18-2 backcross population and quantitative trait loci (QTL) techniques to investigate the interrelationships. Five dormancy, 4 shattering, and 3 awn-length QTLs were detected in the population. Two QTLs for hull color were identified, and the SS18-2- and EM93-1-derived alleles increased the intensity of black, and red or yellow pigmentations, respectively. The only QTL for pericarp color co-located with the red pericarp gene Rc, with the SS18-2-derived allele increasing the intensity of black and red pigmentations. Four of the 5 dormancy QTLs were flanked or bracketed by 1 to 4 QTLs for the interrelated characteristics. The QTL organization pattern indicates the central role of seed dormancy in adaptive syndromes for weedy rice.