Identification of QTLs for seedling vigor in winter wheat uri icon

abstract

  • Seedling vigor is an important trait characterized by rapid development of vegetative cover above the soil surface, particularly in rainfed environments. To elucidate the genetic basis of seedling vigor, 207 F-2:4 lines derived from Jingdong 8/Aikang 58 were investigated in the field at Beijing and Gaoyi, Hebei province, during the 2011-2012 and 2012-2013 cropping seasons. A total of 148 SSR markers polymorphic between the parents, and the RhtD1b-specific marker were used to map QTL for seedling vigor by inclusive composite interval mapping (ICIM). Normalized difference vegetation index (NDVI) and ground cover (GC) before winter and in late spring showed a continuous distribution. Significant differences in NDVI and GC among lines were detected. Broad-sense heritability of NDVI and GC ranged from 0.69 to 0.74 based on the mean values averaged across four environments. GC was highly correlated with NDVI (r = 0.74-0.85, P < 0.001). Four seedling traits were positively correlated with thousand kennel weight and grain yield. Thirty-seven QTLs distributed on 14 chromosomes for the seedling traits were identified; 18 were on genome A chromosomes, 8 on genome B chromosomes and 11 on genome D chromosomes. QTLs QGCs.caas-3B.1, QGCw-caas-1D and QGCw-caas-5D explained more than 20 % of the phenotypic variation in seedling traits, with over-dominance effects. QGCw.caas-1A.1, QNDVIw-caas-6D, QGCs-caas-6A, QGCs-caas-2A.2, QNDVIs-caas-3A, and QGCw-caas-5B explained more than 10 % of the phenotypic variation in seedling traits. The major QTLs QGCs-caas-6A and QGCw.caas-5B showing strong additive effects and linked with agronomic traits, could be used for molecular marker-assisted selection to improve seedling vigor and yield-related traits.

publication date

  • 2014
  • 2014