Submitted to: American Society of Agronomy
Publication Type: Other
Publication Acceptance Date: 7/20/2002
Publication Date: 10/30/2003
Citation: SANTOS, A., MURPHY, J.P., LIVINGSTON, D.P. IDENTIFICATION OF OTL'S FOR FREEZING RESISTANCE IN WINTER OAT USING AFLP.. AMERICAN SOCIETY OF AGRONOMY. 2003. Interpretive Summary: A procedure to associate fragments of DNA with certain agronomic characteristics may be useful for breeders because it takes less time to extract the DNA ia a laboratory than to grow plants and subject them to various tests to determine whether they have the desirable characteristics. To evaluate this procedure with regard to winter hardiness, a winter hardy (Wintok) cultivar was crossed with a non-winter hardy (Fulghum) cultivar and their progeny were advanced several generations while maintaining a family structure. Two hundred and twenty families were developed and subjected simultaneously to DNA fragment analysis and freeze testing. Four fragments were found to be associated with freezing tolerance and two of those accounted for 66% of the genetic variation for freezing. These results suggests that the specific DNA fragments could be used to select winter hardy individuals and would work well in a breeding program to develop winter hardy germplasm.
Technical Abstract: Quantitiative trait loci (QTL) have been identified in barley and wheat that are linked to winter hardiness. To identify QTL for components of winter hardiness to use in marker assisted selection in oats a population of recombinant inbred lines (RILs) developed through single-seed descent from the cross "Wintok (winter-hardy)x "Fulghum" (winter-tender). Plants were grown under controlled conditions fro five weeks, then transferred to a hardening chamber for three weeks. Plants were harvested and crowns were prepared and subjected to a second-phase hardening at -3 degrees C before being frozen at -10 degrees C. After freezing the crowns were replanted and allowed to grow for three weeks. Individual plants were visually rated from 0 to 5, where 0=dead, and 5=undamaged. The 220 RILS were also planted in a replicatred field trial. The AFLP method was performed as described by Vos et al, 1995. One hundred forty markers were identified from 11 primer combinations. The 68 that segregated 1:1 were used in the construction of a linkage map. Ten linkage groups were identified with a total length of 682.3 cM and an average distance of 18.5 cM between markers. Composite Interval Mapping identified four QTLs for freezing, three QTLs days to heading and one QTLs for plant height (Table1). Plot mean heritability for freezing was O.30 with markers ags8 and jpm1 together having an R2 of 0.197. These two QTL's accounted for 66% of the genetic variation for freezing.