PJB-2018-783
IN VITRO SELECTION OF DROUGHT TOLERANT DURUM WHEAT (TRITICUM DURUM DESF.) VARIETIES
Afef Othmani
Abstract
Drought stress is the main problem limited durum wheat production in Tunisia. Screening of drought tolerant genotypes is perquisite for wheat production under water deficit In this order, laboratory experiments of 11 durum wheat varieties were carried to evaluate their response to water stress induced by different concentrations of polyethylene glycol (PEG-6000) and to screen drought tolerant varieties at i) callus level using immature embryos grown in MS medium ii) seedling level, where wheat varieties were raised in hydroponic and nourished with Hoagland solution. Experiments were carried out at National Agronomic Institute of Tunisia. For most studied traits, significant differences (p<0.05, p<0.01 and p<0.001) were observed among PEG treatments and genotypes. For callus culture, increasing PEG concentration decreases relative growth rate, callus water content, relative water content, in vitro tolerance and relative tolerance. PEG-treated hydroponic culture significantly decrease seedling shoot length, seedling root length, root to shoot ratio, relative water content, chlorophyll (a), chlorophyll (b) and total chlorophyll, but it increase free proline content. In vitro screening of drought tolerant genotypes based on 1) immature durum wheat callus traits using biplot analysis, mean rank and standard deviation of ranks and 2) seedling traits, Mahmoudi, by its great performances, seems to be the most drought tolerant variety. In vitro selection can be useful tool for preliminary screen for drought tolerant genotypes.
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