Mapping the QTLs underlying drought stress at developmental stage of sorghum (Sorghum bicolor (L.) Moench) by association analysis

• Published in: Euphytica 2013-10, Vol.193 (3), p.433-450
• Main Authors: Sakhi, Shazia, Shehzad, Tariq, Rehman, Shafiqur, Okuno, Kazutoshi
• Format: Article
• Language: English
• Subjects: Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Chromosomes; Classical and quantitative genetics. Population genetics. Molecular genetics; Developmental stages; Drought; Drought resistance; Fundamental and applied biological sciences. Psychology; Gene mapping; Generalities. Genetics. Plant material; Genetic markers; Genetics and breeding of economic plants; Genomics; Life Sciences; Molecular genetics; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant Sciences; Plant tolerance; Quantitative genetics; Sorghum; Varietal selection. Specialized plant breeding, plant breeding aims
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1007/s10681-013-0963-6

This study was conducted to identify quantitative trait loci (QTLs) for drought tolerance in sorghum ( Sorghum bicolor (L.) Moench) by association mapping using a simple sequence repeat (SSR)-marker-based diversity research set. Genotypic data for 98 SSR marker loci on ten chromosomes were used for the association analysis. The experiment was conducted under control (well-watered) and drought stress conditions, and the phenotypic values of 23 morphological traits were recorded. Drought tolerance was assessed by using a leaf drying score as a parameter of the tolerance/susceptibility: scores were assigned on a scale from 1 (most tolerant) to 9 (most susceptible). Under the control conditions, 17 QTLs associated with 12 traits were identified on chromosomes 1, 2, 4, 8, 9, and 10, with −Log 10 ( P ) ranging from 2.5 to 7.6 and explaining 9.5–57.5 % of the total phenotypic variance for the traits. Under the drought stress conditions, nine QTLs associated with 8 traits were identified on chromosomes 1, 2, 3, and 10 that explained 9–61.2 % of the total phenotypic variance for the traits, with −Log 10 ( P ) ranging from 2.5 to 3.5. QTLs for some traits were detected only under the drought stress condition, suggesting that these traits are important in drought tolerance. These QTLs could be used to further dissect the genetic and physiological basis of drought tolerance in sorghum.