Kouighat Mohamed, Hanine Hafida, El Fechtali Mohamed, Nabloussi Abdelghani
Research Unit of Plant Breeding and Plant Genetic Resources Conservation, National Institute of Agricultural Research, Regional Agricultural Research Center of Meknes, Meknes 50000, Morocco.
Laboratory of Bioprocess and Bio-Interfaces, Faculty of Science and Technology, University Moulay Slimane, Béni-Mellal 23000, Morocco.
Plants (Basel). 2021 Jun 8;10(6):1166. doi: 10.3390/plants10061166.
In the context of climate change and water scarcity, there is a need to develop and use drought-tolerant sesame cultivars. This study was conducted to evaluate the response of 13 sesame genotypes, including 11 mutants and their wild-types, to drought during germination and early seedling growth. Moderate and severe drought stress was simulated by applying polyethylene glycol (PEG) at two osmotic potentials, -0.6 MPa and -1.2 MPa, respectively, on seeds of two successive mutant generations, M and M. The parameters measured or calculated were germination percentage (GP), germination rate (GR), mean germination time (MGT), root length (RL), shoot length (SL), root to shoot ratio (RSR), and the seedling vigor index (SVI). Results showed the significant effect of genotype, drought, and drought × genotype interaction on all parameters investigated. Under severe drought, seeds of seven genotypes, including wild types, were not able to germinate. There was a drastic decline of all parameters for the rest, except MGT and RSR, which markedly increased. Interestingly, two mutants, "ML2-5" and "ML2-10", were identified as the most tolerant to severe drought and the most stable over both generations. The present work is the first report of sesame germplasm with such a high level of tolerance to drought during germination and early seedling growth stages.
在气候变化和水资源短缺的背景下，有必要培育和使用耐旱芝麻品种。本研究旨在评估13个芝麻基因型（包括11个突变体及其野生型）在萌发和幼苗早期生长阶段对干旱的响应。通过分别在两个连续突变世代M和M的种子上施加两种渗透势（-0.6 MPa和-1.2 MPa）的聚乙二醇（PEG）来模拟中度和重度干旱胁迫。所测量或计算的参数包括发芽率（GP）、发芽速率（GR）、平均发芽时间（MGT）、根长（RL）、苗长（SL）、根冠比（RSR）和幼苗活力指数（SVI）。结果表明，基因型、干旱以及干旱×基因型互作对所有研究参数均有显著影响。在重度干旱条件下，包括野生型在内的7个基因型的种子无法萌发。其余基因型的所有参数均急剧下降，但MGT和RSR显著增加。有趣的是，两个突变体“ML2 - 5”和“ML2 - 10”被鉴定为对重度干旱耐受性最强且在两个世代中最稳定的品种。本研究是关于芝麻种质在萌发和幼苗早期生长阶段对干旱具有如此高耐受性的首次报道。
