Screening for drought resistance during germination of modern and old Iberian wheat cultivars

Abstract

Climate change is expected to reduce water availability in several wheat (Triticum aestivum L.) growing areas. Drought, during and immediately after sowing can compromise germination, seedling development, and ultimately crop yield. Our study’s objective was to investigate early drought stress resistance and evaluate genetic diversity of four bread wheat cultivars – three modern elite germplasm lines (‘Antequera’, ‘Jordão’ and ‘Roxo’) and an ancient Portuguese cultivar (‘Mestiço’) – at five water potentials, ranging from 0 to –1.5 MPa. Germination was annotated daily during eight days. Dry and fresh weights as well as root and shoot growth were measured. Genetic variability among cultivars was evaluated using start codon targeted (SCoT) markers. Overall, when water potential was lowered, germination rate and seedling growth were delayed. Final germination percentages were only affected by the higher stress intensity. This study reinforces the importance of research into ancient wheat cultivars, such as ‘Mestiço’. This cultivar showed the highest genetic difference when compared with the remaining cultivars. ‘Mestiço’ presented the highest coleoptile size, high vigor index values, and the lowest variation in water content due to stress conditions. Therefore, it may be able to germinate in extremly dry soil and be the least affected by drought stress. Still, due to the comparatively reduced yield of older wheat cultivars, stress tolerance should be researched within elite cultivars. Among these, Jordão revealed particularly good germination and early biomass development characteristics across water potentials, presenting a likely choice for future studies under drought stress conditions.

Drought tolerance of three ethnomedicinal shrubs evaluated based on their seed germination rates at different drought levels induced by using polyethylene glycol (PEG6000)

“…On the other hand, the germination velocity (GV) dropped steeply with falling water potential (0 MPa, 17% vs -0.5 MPa, 1.2%, S. incana); (0 MPa, 24% vs -0.5 MPa, 3.5%, S. ocymastrum) and (0 MPa, 38.1 % vs -1 MPa, 14.8%, T. fontanesii). A remarkable delay in germination with the decrease in water potential was observed also by other authors (Al-Taisan et al, 2010;Dadach and Mehdadi, 2018b;Pavia et al, 2019).…”

“…Furthermore, water stress may disrupt mechanisms leading to radicle protrusion, therefore the seed germination triggering is postponed (Gill et al, 2003). The processes used for controlled drought simulation at laboratory include treating seeds with polyethylene glycol (PEG), a nonionic water polymer restraining water percolation through the seed coat (Pavia et al, 2019).…”

Foliar application of 5-aminolevulinic acid alleviated high temperature and drought stresses on wheat plants at seedling stage

“…It is critical to increase wheat production to meet the food security (Sharma et al, 2015). However, wheat growth can be affected by drought and temperature stress at any developmental stage (Pavia et al, 2019).…”

Principal component analysis and comprehensive evaluation on drought tolerance difference of canola cultivars at germination and emergence stages

“…In recent years, the comprehensive evaluation had already been preliminarily applied to identify drought-resistant germplasm, such as wheat, corn, soybean and other crops (Khodarahmpour and Motamedi, 2011;Ali et al, 2018;Farid and Ridwan, 2018;Liu et al, 2019b;Pavia et al, 2019). The comprehensive evaluation was involved in the principal component analysis, membership function analysis, regression analysis and cluster analysis of drought tolerance indices correlation for different varieties.…”

“…There is no correlation among these comprehensive indicators, which could present overall information from the original multiple indices related to canola drought resistance. It is gradually applied to evaluate some crops drought tolerance comprehensively (Liu et al, 2016;2019a;Pavia et al, 2019).…”