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Vegetative growth and water use efficency characterization of durum wheat near isogenic lines for the QTL Qyld.idw-3B
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Edité par CCSD ; University of of Natural Resources and Applied Life Sciences (BOKU) -
The study of the genetic basis of grain yield is one of the major challenges of the scientificcommunity because of both its complex genetic control and the strong interaction withenvironment and management practices. Furthermore, such interactions may affect yield duringthe entire life cycle of the plant. It is therefore crucial to consider yield as the result of multiplesimpler traits and thus study their genetic control separately. In this study, we used the phenotypingplatform PhenoArch in order to identify growth and water use related traits that may explain thesegregation for yield and plant height observed at the QTL Qyld.idw-3B by Graziani et al. (2010).Four pairs of durum wheat near-isogenic lines (NILs) for the QTL Qyld.idw-3B were grown at threelevels of drought stress: no stress (soil water potential > -1 bar), mild stress (soil water potential of-5/-8 bar) and severe stress (soil water potential ≈ -13 bar). The stress was applied at the beginningof stem elongation until the end of the experiment (late milk stage, Zadok 77) on eight replicatesper genotype per treatment. We recorded two main types of phenotypic data: (i) canopy imagesand (ii) weight measurements: every night, digital RGB images were collected. From these imageswe estimated several growth related phenotypes like biomass, leaf expansion and plant height;every plant was weighted to estimate the evapotranspiration at least once per day. Combining thesedata, it was possible to evaluate key physiological parameters like water use efficiency (WUE) andleaf transpiration. The QTL seemed to not affect vegetative behaviour and water use of plants duringthe early vegetative stages while majorly differentiating the NILs couples during the reproductiveand earl ripening stages. This explains the segregation for final plant height previously observed byGraziani et al (2010). These results may provide useful information for further phenotypic as well asphysiological and genetic characterization of the QTL Qyld.idw-3B with a main focus on mid to latestem elongation and reproductive/maturity stages.
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