Screening of wheat genotypes response under drought controlled conditions
Authors: Saşco Elena 
Published: November 2024

The present study was carried out to estimate the response of native wheat genotypes (Tri-ticum aestivum L.) Moldova 614, Moldova 66 and the Selania/Accent line to water stress in the early stages of growth and to use sources with a high level of adaptability in resistance improve-ment programs to drought. The eﬀect of osmotic stress on early growth stages was evaluated un-der temperature conditions of 15oC and 25oC, using polyethylene glycol (PEG 6000) treatment at concentrations of 10% and 20% d/v. In the conditions of water restrictions produced by PEG 6000 in the 10% concentration both at the optimal temperature of 25oC, but also at the suboptimal one of 15oC, the investigated indices showed the response of tolerance, but also of high resistance. When administering the osmotic in the concentration of 20% at a temperature of 25oC, both the average resistance and the sensitivity of the investigated characters were attested. Moldova 614 recorded the lowest reduction of 23.7% for plant vigor index, while L Selania/Accent recorded a massive reduction of 72.8% for seed vigor index. In the conditions of interaction of major stress factors (PEG 20% x 15oC) the genotypes responded with a severe decrease of the inves-tigated parameters. More advantageous PVI was attested only in the Moldova 614 genotype. The variance analysis revealed the temperature factor with the highest weight in the variability of the root and stem length characters (85.7% and 72.2%). The water deﬁcit explained respec-tively 12.0% and 22.5% of the variance of the characters, while the signiﬁcant interactions of the stress factors attested advanced weight for the length of the stem in relation to the length of the root. This phenomenon indicates the increased vulnerability of the stem, a phenomenon also highlighted by the phenotypic character of the root/stem ratio. Purpose.Wheat contributes to global consumption with 55% of carbohydrates, but also 20% of food calories, maintaining an important position in the international grain trade [3]. Abiotic stress extremes such as drought, temperature, salinity, and nutrient imbalance represent major challenges to the grain industry. Drought aﬀects plant growth from germination to matu-rity, causing morphological, biological, physiological, and molecular changes. More likely to be aﬀected are the stages of early vegetation and reproduction [3]. Tolerance to water deﬁcit as well as thermal stress is a diﬃcult, polygenic quantitative characteristic [2, 3]. In eﬃcient and repeatable phenotypic expression of drought tolerance, it is necessary to use simple early scre-ening methods [2, 4]. One of the sources of improving wheat drought tolerance is presented by the introgression of resistances from the wild gene pool as well as local ones [3]. Anticipating testing in ﬁeld conditions, targeted are the tolerance indices in the early growth phase under artiﬁcially stressful conditions [2, 4]. The present study aimed to select local wheat genotypes, well adapted to the induction of water stress by the osmotic PEG 6000 under diﬀerent tempe-rature conditions.