Document Type : Research Paper
Authors
1 Graduate student of plant breeding, University of Yasouj, Yasouj, Iran
2 Department of Agronomy and Plant breeding, Faculty of Agriculture, University of Yasouj, Yasouj, Iran
3 Faculty of Agriculture, University of Yasouj, Yasouj, Iran
4 Dryland Agricultural Research Inistitute, Agricultural Research, Education and Extension Organization, Gachsaran, Iran
Abstract
Objective: Cold stress causes irreparable losses to plants including lentils (Lens culinaris Medic) as one of the important legumes. Limited information is available on the use of somaclonal variation for improving cold tolerance in lentils. This study aimed to investigate the cold tolerance in lentil seedlings regenerate from in vitro culture.
Methods: To investigate cold tolerance, regenerated seedlings of seven lentil genotypes were exposed to two temperature conditions of 5 and 25˚C. The experiment was conducted at each temperature level in a completely randomized design with three replications at the Yasouj Agricultural Faculty in 2021. Ten days after application temperature treatments, physiological and morphological traits including root length, root fresh and dry weight, shoot height, shoot fresh and dry weight, carotenoid and chlorophyll contents, electrolyte leakage and total soluble sugar content were measured.
Results: The results of the combined analysis of variance showed that the effect of temperature for all traits; the effect of genotype for all traits except root length, and the interaction of temperature and genotype for all traits except shoot height, carotenoid, and chlorophyll content were significant. At the temperature of 5˚C (cold stress), the genotype 09S 83259-14ILL6994/ILL5480 had more values than the other genotypes in terms of most traits. Classification of genotypes using the three-dimensional plot of the first three factor scores introduced the genotypes ILL 7979 and 09S 83259-14ILL6994/ILL5480 as the most tolerant genotypes under cold stress conditions. The genotypes Gachsaran, Kimia, ACC 5588 ILL116 Sel and ACC 4605 were identified as cold-sensetive. Among the traits measured at the vegetative stage, the electrolyte leakage trait had the highest stress intensity value (0.53), indicating that this trait was more affected by cold temperature than other traits. The genotypic and phenotypic variation coefficients showed that the genotypes had the most diversity for the measured traits related to the shoot. The highest broad-sense heritability was related to total soluble sugar (97.81%) and electrolyte leakage (97.70%), and the lowest was related to root length (88.02%).
Conclusion: In general, the results showed that there was sufficient genetic diversity of cold tolerance among the seedlings regenerated from the tissue culture of the genotypes. In this study, by measuring the components of genetic variance, it was determined to some extent that the contribution of genetic variance is greater than epigenetic factors for key traits. The high proportion of genetic variance in this study indicates that selection under tissue culture conditions for cold tolerance in lentils will be effective. In addition, important traits such as electrolyte leakage, and fresh and dry weight of the shoot were severely affected by cold stress, which can probably be used as a selection criterion for cold tolerance in lentils. These results can be used in breeding programs to improve cold tolerance in lentils.
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