Quantitative trait loci analysis of stele traits of rice (Oryza sativa) under well-watered and drought conditions

Abstract

© 2020, Thai Society of Higher Eduation Institutes on Environment. All rights reserved. Drought is a major yield-limiting factor for rice production. In drying soils, plants experience water scarcity and soil compaction. Penetration of deep roots in hard soil can improve crop productivity under drought. It has been shown that stele is an important anatomical predictor for root penetrability. Here, we studied genetic controls of root stele by quantitative trait loci analysis (QTL). One hundred and thirty-five chromosome segment substitutive lines derived from a cross between, KDML 105 and IR68586-F2-CA-31 (DH103) and IR68586-F2-CA-143 (DH212) were used as mapping population. Plants were grown in the field under well-watered and drought conditions. Under drought, rice decreased leaf weight by 16.63% but increased stele area by 20.21%. Stele traits were significantly correlated with root thickness in well-watered (r= 0.57) and drought conditions (r= 0.70). We identified 4 SNP markers on chromosomes 1, 4, and 9 which explained 9.47% to 11.36% of individual phenotypic variance. A marker on chromosomes 1 were found to be co-localized with previously described QTL for basal root thickness in double haploid rice mapping populations. These markers could be further developed to assist in rice breeding program.