Chickpea (Cicer arietinum L.) is an important grain legume crop but its sustainable production is challenged by predicted climate changes, which are likely to increase production limitations and uncertainty in yields. Characterising the variability in root architectural traits in a core collection of chickpea germplasm will provide the basis for breeding new germplasm with suitable root traits for the efficient acquisition of soil resources and adaptation to drought and other abiotic stresses. This study used a semi-hydroponic phenotyping system for assessing root trait variability across 270 chickpea genotypes. The genotypes exhibited large variation in rooting patterns and branching manner. Thirty root-related traits were characterised, 17 of which had coefficients of variation ≥0.3 among genotypes and were selected for further examination. The Pearson correlation matrix showed a strong correlation among most of the selected traits (P≤0.05). Principal component analysis revealed three principal components with eigenvalues >1 capturing 81.5% of the total variation. An agglomerative hierarchical clustering analysis, based on root trait variation, identified three genotype homogeneous groups (rescaled distance of 15) and 16 sub-groups (rescaled distance of 5). The chickpea genotypes characterised in this study with vastly different root properties could be used for further studies in glasshouses and field trials, and for molecular marker studies, gene mapping, and modelling simulations, ultimately aimed at breeding germplasm with root traits for improved adaptation to drought and other specific environments.
The targeted QTL is confirmed to harbor core genes related to hormone signaling pathways that can be exploited as a key genomic region for marker-assisted selection. The candidate genes and SNP/indel markers detected in this study are valuable resources for understanding the mechanism of PHS resistance and for marker-assisted breeding of the trait in wheat.
Abstract The grain legume grass pea ( Lathyrus sativus L.) is adapted to drought‐prone environments, but the extent and mechanisms of its tolerance are not well understood. In a pot experiment, water deficit was imposed on plants by withholding water from first flowering until predawn leaf water potential (LWP pd ) was −3.12 MPa. Water deficit reduced dry matter, seed yield, harvest index and water use efficiency by 60 %, 87 %, 67 % and 75 %, respectively, when compared with the controls. Flower production stopped when LWP pd fell to −1.8 MPa. At LWP pd −1.5 MPa, only 25 % of flowers resulted in filled pods (compared with 95 % filled pods in the control) with the rest aborted as flowers (48 %) or pods (27 %). Filled pods had more aborted ovules than controls, resulting in 29 % less seeds per pod. Water deficit reduced pollen viability, germination and the number of pollen tubes reaching the ovary by 13 %, 25 % and 31 %, respectively. Emergence from seeds produced from water‐deficient plants was 21 % less than controls, but seedling shoot dry mass was 18 % higher, in accordance with the 19 % higher seed mass. The sensitivity of flowering to drought limited pod numbers but enabled plants to retain existing pods and develop near‐normal seeds with low β‐ N ‐oxalyl‐ l ‐α‐β‐diaminopropionic acid toxin concentrations. This trait is useful for farming systems reliant on harvested seed for the next crop and in cases where seed size influences the value of the product.
