Genetic Insight into Yield-Associated Traits of Wheat Grown in Multiple Rain-Fed Environments

Background: Grain yield is a key economic driver of successful wheat production. Due to its complex nature, little is known regarding its genetic control. The goal of this study was to identify important quantitative trait loci (QTL) directly and indirectly affecting grain yield using doubled haploid lines derived from a cross between Hanxuan 10 and Lumai 14. Methodology/Principal Findings: Ten yield-associated traits, including yield per plant (YP), number of spikes per plan

Association mapping for yield and grain quality traits in rice (Oryza sativa L.)

Association analysis was applied to a panel of accessions of Embrapa Rice Core Collection (ERiCC) with 86 SSR and field data from two experiments. A clear subdivision between lowland and upland accessions was apparent, thereby indicating the presence of population structure. Thirty-two accessions with admixed ancestry were identified through structure analysis, these being discarded from association analysis, thus leaving 210 accessions subdivided into two panels. The association of yield and grain-quality traits with SSR was undertaken with a mixed linear model, with markers and subpopulation as fixed factors, and kinship matrix as a random factor. Eight markers from the two appraised panels showed significant association with four different traits, although only one (RM190) maintained the marker-trait association across years and cultivation. The significant association detected between amylose content and RM190 was in agreement with previous QTL analyses in the literature. Herein, the feasibility of undertaking association analysis in conjunction with germplasm characterization was demonstrated, even when considering low marker density. The high linkage disequilibrium expected in rice lines and cultivars facilitates the detection of marker-trait associations for implementing marker assisted selection, and the mining of alleles related to important traits in germplasm

Thai jasmine rice cultivar KDML105 carrying Saltol QTL exhibiting salinity tolerance at seedling stage

Saltol, the major salinity tolerance quantitative trait loci (QTL) in rice, was introgressed from IR66946-3R-230-1-1 (FL530) into Khao Dawk Mali 105 (KDMl105) by two rounds of marker-assisted backcrossing (MAB). Twenty-eight BCF introgression lines (BILs) with positive Saltol allele (BIL) and 19 BILs with negative Saltol allele (BIL) were validated for the effect of Saltol as key salinity tolerant trait at seedling stage. A hydrophonic system with salt stress of 12\ua0dS\ua0m (130\ua0mM Na) was conducted, and significant differences between BILs and BILs were observed for the period of plant survival (PPS), total K (T-K) and Na (T-Na) concentration, whole plant Na-K ratio (T-Na/K), shoot Na (S-Na) and K (S-K) concentration, and shoot Na-K ratio (S-Na/K). BILs displayed higher PPS, uptake less Na (T-Na; 43.4\ua0ppm), and more K (T-K; 30.9\ua0ppm), while the BILs uptake more Na (T-Na; 45.7\ua0ppm) and less K (T-K; 28.2\ua0ppm). Direct effects on PPS and salt injury score (SIS) were observed, indicating Na/K homeostasis mechanism by the Saltol under hydrophonic salt stress. All BILs recovered KDML105 cooking quality profile such as low apparent amylose content (AAC), high score of alkaline spreading value (ASV), intermediate gel consistency (GC), and strong fragrance. However, variation in agronomic traits was observed. The possibility of lowering S-Na/K ratio under salt stress at seedling stage in KDML105 by introgression of the Saltol was demonstrated. Currently, BCF of the BIL selected lines are being tested for salinity tolerance in the salt-affected areas in the northeast of Thailand