Selection of wheat genotypes for biomass allocation to improve drought tolerance and carbon sequestration into soils

Abstract

The biomass allocation pattern of plants to shoots and roots is a key in the cycle of elements such as carbon, water and nutrients with, for instance, the greatest allocations to roots fostering the transfer of atmospheric carbon to soils through photosynthesis. Several studies have investigated the root to shoot ratio (R:S) biomass of existing crops but variation within a crop species constitutes an important information gap for selecting genotypes aiming for increasing soil carbon stocks for climate change mitigation and food security. The objectives of this study were to evaluate agronomic performance and quantify biomass production and allocation between roots and shoots, in response to different soil water levels to select promising genotypes for breeding. Field and greenhouse experiments were carried out using 100 genotypes including wheat and Triticale under drought-stressed and non-stressed conditions. The experiments were set-up using a 10 × 10 alpha lattice design with two replications under water stress and non-stress conditions.The following phenotypic traits were collected: number of days to heading (DTH), number of productive tillers per plant (NPT), plant height (PH), days to maturity (DTM), spike length (SL), kernels per spike (KPS), thousand kernel weight (TKW), root biomass (RB), shoot biomass (SB), root to shoot ratio (R:S) and grain yield (GY).There was significant (p < 0.05) variation for grain yield and biomass production because of genotypic variation. The highest grain yield of 247.3 g/m 2 was recorded in the genotype LM52 and the least was in genotype Sossognon with 30 g/m 2 .Shoot biomass ranged from 830 g/m 2 (genotype Arenza) to 437 g/m 2 (LM57), whilst root biomass ranged between 603 g/m 2 for Triticale and 140 g/m 2 for LM15 across testing sites and water regimes. Triticale also recorded the highest R:S of 1.2, whilst the least was 0.30 for wheat genotype LM18. Overall, drought stress reduced total biomass production by 35% and R:S by 14%. Genotypic variation existed for all measured traits useful for improving drought tolerance, whilst the calculated R:S values can improve accuracy in estimating C sequestration potential of wheat. Wheat genotypes LM26, LM47, BW140, LM70, LM48, BW152, LM75, BW162, LM71 and BW141 were selected for further development based on their high total biomass production, grain yield potential and genetic diversity under drought stress.

Effects of Low Water Availability on Root Placement and Shoot Development in Landraces and Modern Barley Cultivars

“…On the contrary, plants under drought tended to invest more in root biomass for most genotypes, as revealed by the reduced S/R ratios in this condition (Table 2). Intra-specific variation for assimilate partitioning between roots and shoots has been found in wheat [55][56][57], generally with relatively larger roots in landraces [55,56]. In our case, we did not observe overall differences in S/R ratio between landraces and cultivars, but we did find genetic variability among the landraces for assimilate partitioning.…”

Variability and selection among mutant families of wheat for biomass allocation, yield and yield‐related traits under drought‐stressed and non‐stressed conditions

“…Traits with high loading on the first and second PCs are important for selection as they are able to discriminate the genotypes more effectively compared to traits with less contributions (Shlens, 2014;Zhang & Castelló, 2017;Zuśka et al, 2019). The differences in trait contributions to the total variation observed among the genotypes under different water regimes were in line with findings from Mwadzingeni et al (2016) and Mathew et al (2019). Similarly, families plotted in the positive quadrants of the first principal component axis (Figures 1 and 2) can be selected as genetic resources for improving above-ground traits.…”

“…Similarly, the strategy could be extended to select genotypes with favourable biomass allocation using root-shoot ratio and shoot biomass, which are more easily measurable compared with root biomass. Mathew et al (2019) used selection for root-to-shoot ratios and shoot biomass to indirectly improve biomass allocation for drought tolerance and carbon sequestration in wheat. Under water-stressed condition, the high positive loadings of productive tiller number, shoot biomass, total biomass, root biomass, root-shoot ratio and grain yield on the first two PC axes indicate the importance of selecting families based on these traits for drought tolerance and increased biomass (Table 5).…”

Non-Invasive Phenotyping Reveals Genomic Regions Involved in Pre-Anthesis Drought Tolerance and Recovery in Spring Barley

“…However, the re-tillering ability of barley (Jamieson et al, 1995) lead to an even slightly higher (although not significant) tiller number at the end of recovery phase compared to control treatment. Although the absolute number of tillers can be increased after drought (Blum et al, 1990), drought stress during the booting stage leads to a reduction in the number of productive tillers and a concomitant decrease in grain number and seed set (Lawlor et al, 1981; Rajala et al, 2010; Mathew et al, 2019).…”