Molecular and Morpho Agronomical Characterization of Recombinant Inbred Lines Advanced Backcross Lines and Elite Cultivars for Physiological and Root Traits in Sorghum Sorghum bicolor L Moench for Drought Tolerance

Abstract

A total of 52 genotypes of sorghum including recombinant inbred lines, advanced newlinebackcross lines and elite cultivars were evaluated under water stress and well-watered newlineconditions during rabi seasons of 2018-19 and 2019-20 for morphological, physiological and newlineyield-related traits. Root phenotyping was conducted in PVC pipes in the greenhouse under newlinewater stress and well-watered conditions. Physiological traits were significantly associated newlinewith yield-related traits under both conditions. Based on stability analysis and DSI, five newlinegenotypes showed stability and higher grain yield/plant than the checks. Three of the five best newlinestable genotypes (RL 167, STG 44 and RV 146) under water stress condition and two newlinegenotypes (RL 142 and RL 167) under well-watered condition were superior for physiological newlinetraits. Six genotypes (RL 167, RL 34, RV 48, BJV 362, Phule Suchitra and SPV 86) were newlineidentified as best performing (root related-traits) lines only under water stress condition and newlineSTG 44 was best performing under both conditions. newlineA total of 104 SSR markers associated with drought and root-related traits were newlinescreened to determine the molecular diversity and ten markers found to be polymorphic newlineamong the genotypes. The population structure analysis indicated five distinct groups, while newlineprincipal coordinate analysis and dendrogram showed four clusters. Validation of marker-trait newlineassociation using general linear model indicated 20 and 32 major MTAs under water stress newlineand well-watered conditions. Two highly significant markers (Xtxp31 and Xtxp38) were newlinefound to be strongly associated with GLM and EWL under water stress condition. Under newlinewell-watered condition, four highly significant markers (SbAGF08, Xtxp38, Xtxp31 and newlineXSbAGB03) were strongly associated with SCMR_45 DAF, GLA_45 DAF, GLB, GLM and newlineR:S. These four markers identified in this investigation may assist in improving rabi sorghum newlinethrough marker-assisted breeding in sorghum. The superior genotypes identified for yield, newlinephysiological and root-related traits in the present stu