QTL analysis of photosynthesis and water status traits in sunflower (Helianthus annuus L.) under greenhouse conditions

The identification of QTL for several physiological traits in sunflower is described. Traits related to photosynthesis (leaf chlorophyll concentration , net photosynthesis and internal CO2 concentration) and water status (stom atal conductance, transpiration, predawn leaf water potential, and relative water content) were evaluated in a population of recombinant inbred lines under greenhouse conditions. Narrow-sense heritabilities were low to averag e. Using an AFLP linkage map, 19 QTL were detected explaining 8.8-62.9% of the phenotypic variance for each trait. Among these, two major QTL for net photosynthesis were identified on linkage group IX. One QTL co-location was found on linkage group VIII for stomatal movements and water status. Coinc ident locations for QTL regulating photosynthesis, transpiration and leaf w ater potential were described on linkage group XIV. These results lead to t he first description of the organization of genomic regions related to yiel d in sunflower.