A Salt Tolerance Evaluation Method for Sunflower (Helianthus annuus L.) at the Seed Germination Stage

Abstract

Salinity is a major abiotic stress that affects plant growth and development and leads to crop yield loss. Many crop species are more sensitive to salinity stress at the seed germination stage than at other developmental stages. Some studies have shown that sunflower is tolerant to salinity to a certain degree. However, no systematic screening data for sunflower germplasms are available for salinity stress. In this study, 552 sunflower germplasms with different genetic backgrounds were evaluated for salt tolerance. Among them, 30 and 53 sunflower germplasms were identified as highly salt-tolerant and salt-tolerant germplasms, respectively, while 80 and 23 were grouped as salt-sensitive and highly salt-sensitive materials, respectively. Of all the traits tested, the germination index and the germination vigor index were the two most reliable traits, showing the highest correlation with salt tolerance during the seed germination stage of sunflower. Thus, a highly efficient and reliable method for evaluating salinity tolerance of sunflower seed germination was established. These results provided a good foundation for studying salt-tolerance mechanisms and breeding highly salt-tolerant sunflower cultivars.

Identification and Characterization of Wheat Germplasm for Salt Tolerance

“…As one of the most significant abiotic stresses influencing grain yield, salinity has become a great threat to agricultural sustainability, affecting more than 800 million hectares of land around the world [ 1 , 2 , 3 ]. Development of salt-tolerant cultivars is one of the most effective ways to deal with this issue [ 4 ].…”

“…Screening wheat genotypes with salt tolerance has been inhibited by the lack of effective evaluation methods [ 2 , 4 , 19 ]. It is quite imperative to determine growth or physiological parameters as the tolerant index for the evaluation of abiotic stress tolerance [ 4 , 20 , 21 ].…”

Sodium Influx and Potassium Efflux Currents in Sunflower Root Cells Under High Salinity

“…It is the third highest oilseed produced in the world, the fourth vegetable oil and the third protein feed source among oilseed crops. Although sunflower plants exhibit medium salt tolerance, their production is affected by high soil salinity, which is common in arid or semi-arid areas ( Karrenberg et al, 2006 ; Li et al, 2020 ). Understanding response to salinity in sunflowers and, in particular, the molecular basis of its salt tolerance mechanism is central to development of breeding and bioengineering strategies aimed to improve the salt tolerance in this species.…”

“…Therefore, NaCl toxicity is related to a long-term and non-specific disturbance of cellular osmotic, ionic, electric, redox and metabolic balance, inhibiting photosynthesis, respiration, growth, development and reproduction ( Shabala, 2013 ; Demidchik et al, 2014 , 2018 ; Negrão and Schmöckel, 2017 ; Isayenkov and Maathuis, 2019 ). It is generally accepted that Na + is more toxic than Cl − for most plant species ( Shabala, 2013 ; Flowers and Colmer, 2015 ), although the detrimental effect of Cl − should not be underestimated ( White and Broadley, 2003 ; Li et al, 2020 ). The key mechanisms of toxic Na + influx into the root cells is its entry through the plasma membrane-associated non-selective cation channels (NSCCs; Demidchik and Tester, 2002 ; Shabala et al, 2006 ; Demidchik and Maathuis, 2007 ).…”

Selection of sunflower genotypes for salt stress and mechanisms of salt tolerance in contrasting genotypes

“…However, its tolerance to salt stress varies according to the genetic material. Li et al (2020) observed that out of 552 sunflower genotypes, only 30 were considered to be highly tolerant and 53 tolerant to salt in the germination phase under 300 mM NaCl. For the genotype H. annuus L. cv.…”