Document Type : Original Article

Authors

• Soghra Khoramipour ¹
• Masoud Dehdari ²

¹ Graduate student of plant breeding, University of Yasouj, Iran

² Associate Professor, Faculty of Agriculture, University of Yasouj, Iran

Abstract

Introduction
Salinity stress has second rank on crop yield limitation after drought stress in the world. Sorghum is very sensitive to salinity in the vegetative and early reproductive stages متن یا آدرس وب سایتی را تایپ کنید یا سندی را ترجمه کنید.
لغو
ترجمه از: فارسی
but, it has minimum sensitive to salt stress at flowering and grain filling stages. Identification of molecular markers linked to genes controlling key traits that associated with salinity stress tolerance is an important breeding goal programs in the marker assisted selection. Therefore, to study the salt tolerance of 10 genotypes of sorghum and its relationship with microsatellite markers this research was designed.
Materials and methods
Two separate experiments were conducted at the Agricultural College of Yasouj University in 2013. In the first experiment salinity tolerance of ten grain sorghum (Sorghum bicolor L.) genotypes at four salinity levels, including 1.92, 5, 10 and 20 dSm^-1 (By addition of NaCl in Hoagland solution) at seedling stage as factorial experiment based on randomized completely design with three replications were investigated. In the two-leaf stage salt stress treatments were applied gradually. 20 days after the salt stress application the important morphological and physiological characteristics were measured and subjected to statistical analyzes. In the second experiment, DNA was extracted from leaf of above mentioned varieties and PCR was performed using 10 SSR primer pairs. The obtained electrophoresis profiles were scored as zero (no band) and one (present band). Association between markers and some important traits were investigated using binary logistic regression.
 Results and discussion
The results of the analysis of variances in the first experiment revealed that the effect of genotype, salt treatment and their interaction were significant (p≤0. 01) for all the recorded traits. Leaf proline content had the highest genotypic coefficients of variation in moderate saline (52.10%) and non-saline (41.6%) conditions. The highest (95.24%) and lowest (21.15%) broad sense heritability were estimated for leaf area and Mg²⁺ content, respectively. Based on stress intensity values, Na⁺/K⁺ ratio (SI=0.96) most affected by salinity (EC=10 dSm^-1) treatment. Based on genotype classification using the 3-dimensional plot of STI, YS and YP, Sor834, Sor1011, Sor1006 and Sor857 were identified as suitable genotypes in both salt stress and non-stress conditions. In general, by conceding all aspects Sor834 and MTS showed the most tolerance and susceptible genotypes to salinity, respectively. The results of second experiment showed a possible association between some markers and some measured traits. Four SSR markers including Xtxp20, Xtxp354, Xtxp331 and   Xtxp285were linked to salt stress tolerance index (STI).
Conclusions
In general, the results of the first experiment proved genetic diversity of salt tolerance of sorghum at seedling stage. The high heritability of some traits indicated the low role of environment in their control which is accordance to high selection effieciency. Na⁺/K⁺ ratio can be used as selection criteria for salinity tolerance of sorghum at seedling growing stage. The above introduced markers may be used into molecular tools for improved of salt tolerance of sorghum in breeding programs.

Keywords

• Proline
• Stress tolerance index (STI)
• Stress intensity (SI)
• Mineral content