Improving Salt Tolerance in Trifolium alexandrinum L. through Interspecific Hybridization, Polyploidization and Induced Variations

• Published in: Cytology and genetics 2022-06, Vol.56 (3), p.301-311
• Main Authors: Dwivedi, K., Roy, A. K., Kaushal, P., Pathak, S., Malaviya, D. R.
• Format: Article
• Language: English
• Subjects: Abiotic stress; Biomedical and Life Sciences; Biomedicine; Cell culture; Explants; Genetic variability; Genotypes; Germination; Human Genetics; Interspecific hybridization; Mortality; Polyploidy; Salinity; Salinity effects; Salinity tolerance; Seedlings; Soil salinity; Trifolium alexandrinum
• ISSN: 0095-4527; 1934-9440
• DOI: 10.3103/S0095452722030021

Soil salinity significantly affects crop productivity throughout the world. Improving intrinsic salt tolerance of the plants may effectively improve productivity. In vitro evaluation is an effective and quick method allowing utilization of inter and intra genotypic variation in a controlled environment. Trifolium alexandrinum is one of the most important winter season annual fodder crop in India and Mediterranean region. Diverse T. alexandrinum genotypes were evaluated in vitro for salt tolerance. Intra and inter genotypic variability was observed for response to varying levels of salt stress at different growth stages. Germination was adversely affected with increasing salt stress among genotypes, however, three genotypes EC 318954, ISH 34/41, ISH 34/8Y showed 75–80% germination even at 0.75% salt level. High seedling mortality was observed at higher salinity levels except EC 318954 which showed low mortality at 0.50 and 0.75% salinity. Seedlings with normal root growth ranged from 5 to 80% at 0.25 and 0.5% salinity. Based on average Salinity Susceptibility Index (SSI) the ISH progenies were most tolerant (SSI = 0.895) for germination as well as radicle and pumule length, number of leaves and plant weight (SSI = 0.91). ISH progenies, tetraploids, Fahli ecotype and multifoliate showed better tolerance. The study confirmed successful transfer of salinity tolerance from T. apertum to T. alexandrinum . The petiole and hypocotyl explants at moderate salinity and petiole explants at high salinity responded well for in vitro callusing. Calli developed at 0.75% salinity can be a source of developing tolerant lines through natural cell line selection. Embryo culture response of Mescavi genotypes was better than Fahli and Saidi genotypes.