Avances en la identificación de QTL para dormición en sorgo granífero

RODRÍGUEZ, M.V.; CANTORO, RENATA; FERNÁNDEZ, LUIS; CERVIGNI, GERARDO C.L.; GIECO, JORGE OMAR; PANIEGO, NORMA; ZAMBELLI, ANDRÉS; RÍOS, CRISTIAN D.; HEINZ, RUTH; BENECH-ARNOLD, ROBERTO L.

ROSARIO

Simposio; III Simposio Nacional ? I Conferencia Internacional de SORGO. Organizado por la AIANBA y UNNOBA. 24 y 25 de agosto 2016. Pergamino, Bs.As.; 2016

UNNOBA (UNIV. NAC. del NO de BA) y AIANBA (ASOCIACIÓN de ING. AGRÓNOMOS del NORTE de BS.AS.)

Pre-harvest sprouting (PHS) can be a serious problem for sorghumproduction in the central region of Argentina, as grain maturation often takes placeduring rainy weather. The quantitative nature of seed dormancy has made itsmanipulation difficult through classical breeding, and the identification of molecularmarkers quantitatively associated with dormancy in sorghum will help to improvePHS tolerance in this crop. To approach this objective, two sorghum inbred lines withcontrasting dormancy (IS9530 and RedlandB2) were used as parents to obtainsegregating populations (F2:3 and F3:4) and RILs for QTL studies. In a recentlypublished work (Cantoro et al., 2016) we reported results of QTL analysis performedon 190 families. A genetic map encompassing 96 SSR markers and a total length of1331 cM was built. Seed dormancy was phenotyped using a germination index (GI)in F3 and F4 panicles under two contrasting environments. Six seed dormancy QTLfor mature grains were identified (qGI-1, qGI-3, qGI-4, qGI-6, qGI-7 and qGI-9) withQTL Cartographer and QTLNetwork, three of them (qGI-3, qGI-7 and qGI- 9) beingco-localised by both approaches. No epistasis was detected for the identified QTL butQTLxE interaction was significant for qGI-7 and qGI-9. Using the single seeddescendent method, families were advanced into RILs at INTA Castelar, and F6 lineswere used for phenotyping in two consecutive years (2015 and 2016) at the FAUBA(Buenos Aires). A linkage map was done with 107 SNP markers, and preliminarycorrelation analysis identified a potential QTL on same position as qGI-9 in previousmapping populations. QTL analysis on this RIL population phenotyped under at leasttwo environments (years) will allow the study of GXE interaction, but is also thestarting point for the fine mapping of major QTL qGI-9.