Linking phenology, harvest index and genetics to improve chickpea grain yield.

Understanding phenology and its regulation is central for the agronomic adaptation of chickpea. We grew 24 chickpea genotypes in 12 environments to analyse: the environmental and genotypic drivers of phenology; associations between phenology and yield; and phenotypes associated with allelic variants of three flowering related candidate loci: CaELF3a; a cluster of three FT genes on chromosome 3; and an orthologue of the floral promoter GIGANTEA on chromosome 4. A simple model with 3 genotype-specific parameters explained the differences in flowering response to daylength.

Genetics of phenological development and implications for seed yield in lentil.

Understanding phenology, its genetics and agronomic consequences, is critical for crop adaptation. Here we aim to (i) characterize lentil response to photoperiod with a focus on five loci: the lentil ELF3 orthologue Sn, two loci linked to clusters of lentil FT orthologues, and two loci without candidates in chromosomes 2 and 5 (Experiment 1: 36 lines, short and long days in a phytotron), and (ii) establish the phenology-yield relationship (Experiment 2: 25 lines, 11 field environments). A vintage perspective, where we quantify time trends in phenotype over three decades of breeding, links both experiments.

Wheat yield potential can be maximized by increasing red to far-red light conditions at critical developmental stages.

Sensing of neighbours via the Red to Far-Red light ratio (R:FR) may exert a cap to yield potential in wheat. The effects of an increased R:FR inside the canopy were studied in dense wheat mini canopies grown in controlled environments by lowering FR. To distinguish between effects exerted by light sensing and assimilate supply, the treatments were complemented with elevated CO , applied between different developmental timepoints to specifically impact tillering, spike growth, floret fertility and grain filling, in different combinations.

Multi-donor × elite-based populations reveal QTL for low-lodging wheat.

Low-lodging high-yielding wheat germplasm and SNP-tagged novel alleles for lodging were identified in a process that involved selecting donors through functional phenotyping for underlying traits with a designed phenotypic screen, and a crossing strategy involving multiple-donor × elite populations. Lodging is a barrier to achieving high yield in wheat. As part of a study investigating the potential to breed low-lodging high-yielding wheat, populations were developed crossing four low-lodging high-yielding donors selected based on lodging related traits, with three cultivars.

Yielding to the image: How phenotyping reproductive growth can assist crop improvement and production.

Reproductive organs are the main reason we grow and harvest most plant species as crops, yet they receive less attention from phenotyping due to their complexity and inaccessibility for analysis. This review highlights recent progress towards the quantitative high-throughput phenotyping of reproductive development, focusing on three impactful areas that are pivotal for plant breeding and crop production. First, we look at phenotyping phenology, summarizing the indirect and direct approaches that are available.

Pot size matters revisited: does container size affect the response to elevated CO and our ability to detect genotypic variability in this response in wheat?

Many studies have investigated the effect of elevated CO2 (eCO2) in wheat, although few have evaluated the potential of genotypic variability in the response. Such studies are the next logical step in wheat climate change adaptation research, and they will require the evaluation of large numbers of genotypes. For practical reasons the preliminary studies are most likely to be conducted in controlled environments.

High night temperatures during grain number determination reduce wheat and barley grain yield: a field study.

Warm nights are a widespread predicted feature of climate change. This study investigated the impact of high night temperatures during the critical period for grain yield determination in wheat and barley crops under field conditions, assessing the effects on development, growth and partitioning crop-level processes driving grain number per unit area (GN). Experiments combined: (i) two contrasting radiation and temperature environments: late sowing in 2011 and early sowing in 2013, (ii) two well-adapted crops with similar phenology: bread wheat and two-row malting barley and (iii) two temperature regimes: ambient and high night temperatures.

More fertile florets and grains per spike can be achieved at higher temperature in wheat lines with high spike biomass and sugar content at booting.

An understanding of processes regulating wheat floret and grain number at higher temperatures is required to better exploit genetic variation. In this study we tested the hypothesis that at higher temperatures, a reduction in floret fertility is associated with a decrease in soluble sugars and this response is exacerbated in genotypes low in water soluble carbohydrates (WSC). Four recombinant inbred lines contrasting for stem WSC were grown at 20/10°C and 11h photoperiod until terminal spikelet, and then continued in a factorial combination of 20/10°C or 28/14°C with 11h or 16h photoperiod until anthesis.

Genotypic variability in the response to elevated CO of wheat lines differing in adaptive traits.

Atmospheric CO2 levels have increased from ~280ppm in the pre-industrial era to 391ppm in 2012. High CO2 concentrations stimulate photosynthesis in C3 plants such as wheat, but large variations have been reported in the literature in the response of yield and other traits to elevated CO2 (eCO2). Few studies have investigated genotypic variation within a species to address issues related to breeding for specific adaptation to eCO2.

Developmental and growth controls of tillering and water-soluble carbohydrate accumulation in contrasting wheat (Triticum aestivum L.) genotypes: can we dissect them?

In wheat, tillering and water-soluble carbohydrates (WSCs) in the stem are potential traits for adaptation to different environments and are of interest as targets for selective breeding. This study investigated the observation that a high stem WSC concentration (WSCc) is often related to low tillering. The proposition tested was that stem WSC accumulation is plant density dependent and could be an emergent property of tillering, whether driven by genotype or by environment.

Linked gene networks involved in nitrogen and carbon metabolism and levels of water-soluble carbohydrate accumulation in wheat stems.

High levels of water-soluble carbohydrates (WSC) provide an important source of stored assimilate for grain filling in wheat. To better understand the interaction between carbohydrate metabolism and other metabolic processes associated with the WSC trait, a genome-wide expression analysis was performed using eight field-grown lines from the high and low phenotypic tails of a wheat population segregating for WSC and the Affymetrix wheat genome array. The 259 differentially expressed probe sets could be assigned to 26 functional category bins, as defined using MapMan software.

Large root systems: are they useful in adapting wheat to dry environments?

There is little consensus on whether having a large root system is the best strategy in adapting wheat (Triticum aestivum L.) to water-limited environments. We explore the reasons for the lack of consensus and aim to answer the question of whether a large root system is useful in adapting wheat to dry environments.

Environment characterization as an aid to wheat improvement: interpreting genotype-environment interactions by modelling water-deficit patterns in North-Eastern Australia.

Genotype-environment interactions (GEI) limit genetic gain for complex traits such as tolerance to drought. Characterization of the crop environment is an important step in understanding GEI. A modelling approach is proposed here to characterize broadly (large geographic area, long-term period) and locally (field experiment) drought-related environmental stresses, which enables breeders to analyse their experimental trials with regard to the broad population of environments that they target.