Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/10/2007
Publication Date: 7/10/2007
Citation: Wooten, D.R., Livingston, D.P., Jellon, E.N., Boren, K.J., Marshall, D.S., Murphy, J. 2007. An intergenomic reciprocal translocation associated with oat winterhardiness. Crop Science. 47:1832-1840. Interpretive Summary: On rare occasion in plants, large pieces of chromosomes will break and reattach themselves to a different chromosome. This is called a translocation and it happens with regularity in oats between chromosome number 7C and 17. It has been speculated that this translocation has been associated with freezing tolerance so in this research we wanted to confirm this. One hundred and twenty eight lines of plants that were derived from a cross of a winter hardy that had the translocation with a non hardy that did not have the translocation were evaluated for presence and absence of the translocation as well as their freezing tolerance. Results indicated a significant association of freezing tolerance with the translocation, but in some cases the results were not conclusive because there were clearly genes for freezing tolerance on other chromosomes that were not part of the translocation. Research is continuing to evaluate the possibility of using the presence of the translocation to identify freezing tolerant germplasm.
Technical Abstract: The reciprocal intergenomic translocation between hexaploid oat (Avena sp.) chromosomes 7C and 17 (T7C-17) has been associated with the division of cultivated oat into A. sativa (L.) and A. byzantina (C. Koch) species as well as fall and spring growth habit. The objective of this experiment was to use a population of 128 recombinant inbred lines derived from a cross of winter tender ‘Fulghum’ (non- T7C-17) with winter hardy ‘Norline’ (T7C-17) to validate the effect of T7C-17 on the winter hardiness component traits winter field survival and crown freeze tolerance, and evaluate the effects of T7C-17 on heading date, height, and vernalization and photoperiod responses. Crown freeze tolerance, vernalization response, and photoperiod response were evaluated in controlled environment studies. Heading date and plant height were evaluated over two seasons in Kinston, North Carolina, and winter field survival was evaluated in five environments over two seasons in the mountains of North Carolina and Virginia. The translocation did not segregate in the expected 1:1 ratio, and twice as many translocation types as non-translocation types were observed. The translocation was significantly correlated with crown freeze tolerance (r=0.72) and winter field survival (r=0.62). The heritability of crown freeze tolerance was 83% and the heritability of winter field survival was 76%. Field heading date was significantly correlated with translocation status (r=0.20). Plant height, vernalization response, and photoperiod response were not associated with the translocation. These results confirmed the importance of T7C-17 in conferring winter hardiness traits in winter oat, and demonstrated that while Norline had similar T7C-17 crown freeze tolerance genes as the previously investigated winter hardy cultivar Wintok, Wintok had additional winter field survival genes that were associated with the translocation.