QTL analysis in multiple sorghum populations facilitates the dissection of the genetic and physiological control of tillering

Abstract

target environments. The aims of this study were to identify QTL for tillering and component traits associated with the S/D balance or PTT, to develop a framework model for the genetic control of tillering in sorghum. Four mapping populations were grown in a number of experiments in south east Queensland, Australia. The QTL analysis suggested that the contribution of traits associated with either the S/D balance or PTT to the genotypic differences in tillering differed among populations. Thirty-four tillering QTL were identified across the populations, of which 15 were novel to this study. Additionally, half of the tillering QTL co-located with QTL for component traits. A comparison of tillering QTL and candidate gene locations identified numerous coincident QTL and gene locations across populations, including the identification of common non-synonymous SNPs in the parental genotypes of two mapping populations in a sorghum homologue of MAX1, a gene involved in the control of tiller bud outgrowth through the production of strigolactones. Combined with a framework for crop physiological processes that underpin genotypic differences in tillering, the co-location of QTL for tillering and component traits and candidate genes allowed the development of a framework QTL model for the genetic control of tillering in sorghum.

Predicting Tillering of Diverse Sorghum Germplasm across Environments

“…Such differences in early vigor of the main shoot could at least partly explain differences in tillering across C 4 cereals like maize (Zea mays L.), sorghum, and pearl millet [Pennisetum glaucum (L.) R. Br]. Although this resonates with earlier findings (Alam et al, 2014a(Alam et al, , 2014b, it is also clear from the results of this study that a single determinant like PTT is not sufficient for prediction of tillering in sorghum. In monocots, tillering enhancement through axillary meristem initiation is controlled by auxin transport and biosynthesis (reviewed in McSteen, 2009), but the outgrowth is also associated with environmental stimuli and activity of the hormone cytokinin, which travels from the root to the shoot and enters the bud to promote outgrowth .…”

“…The predictive model for tillering provides a connection of FTN to the underpinning, controlling genomic regions via PTT (Alam et al, 2014b), by removing the environmental and management effects on observed FTN in a given location. Knowledge of these context dependencies is essential for meaningful dissection of the phenotypic expression of a complex trait into the underpinning genetic control by its component traits (Messina et al, 2009).…”

“…Knowledge of these context dependencies is essential for meaningful dissection of the phenotypic expression of a complex trait into the underpinning genetic control by its component traits (Messina et al, 2009). For the genetic control of tillering in sorghum, quantitative trait loci associated with PTT and the C demand by the main shoot have been identified (Alam et al, 2014b). Once a more advanced understanding of the function and effect of quantitative trait loci associated with tillering is available, it would be possible to introduce this into a simulation analysis to derive phenotypic consequences associated with specific regions or combinations of regions, in a manner similar to that done for maize leaf growth by Chenu et al (2009).…”

Ultra-high-throughput DArTseq-based silicoDArT and SNP markers for genomic studies in macadamia

“…DArTseq-based SNPs are co-dominant markers. Both types of markers have been successfully applied in several crop species for genetic diversity [37–41], genetic mapping [36, 42–44], and population structure [45, 46] studies. The present study is the first to utilize the DArT platforms in macadamia; we present the development of DArT marker platforms, and compare and analyse the usefulness of silicoDArT and SNP markers for genomic studies.…”

Whole-Genome Analysis of Candidate genes Associated with Seed Size and Weight in Sorghum bicolor Reveals Signatures of Artificial Selection and Insights into Parallel Domestication in Cereal Crops

“…The amount of assimilate per seed is driven by factors affecting both seed number and assimilate supply. Total seed number per plant is determined by the number of seeds per panicle and the number of panicles per plant (i.e., tillering and branching), which are affected by a range of genetic and environmental factors (Alam et al, 2014). A negative correlation between seed size and seed number has been observed frequently in cereals (Jakobsson and Eriksson, 2000; Acreche and Slafer, 2006; Peltonen-Sainio et al, 2007; Sadras, 2007).…”