The global population is rapidly increasing and it is projected to reach approximately 9.7 billion by 2050 which intensifies the demand for food, water, and other resources, putting immense pressure on agricultural systems. Climate change is causing more frequent and severe weather events, including droughts, floods, and heatwaves which threatens global food security. To address the dual challenges of population growth and climate change, developing drought-resistant crops is crucial. By investing in the development of droughtresistant crops, we can enhance the resilience of agricultural systems, mitigate the impacts of climate change, and ensure a sustainable future for global food production. which requires exploration of variability present in crop plants.

Selection for novel genotypes with robust root systems is vital to complement agronomic trait selection and develop high-performing, climate-smart crop varieties. However, most breeding programmes focus on ideotype development based on selection of aboveground phenotypic traits without involving the critical root attributes. There are at least two major limitations that challenge breeding for improved agronomic attributes and root system architecture. i.e., root sampling from field-grown plants and limited understanding of the genetic control of root traits for genetic recombination and selection. Which has hindered progress in genetic analysis of root traits to elucidate their phenotypic and genotypic expression2. Phenotypic variation of root traits manifests from the genetic constitution and its interaction with environmental factors. Polygenes, each with minor effects were found to control the basic structure of root traits and their response to soil conditions. In Rice crop, QTLs for root and shoot traits at the vegetative growth stage were identified using a genotyping by sequencing (GBS) based saturated SNP linkage map. Analysis of genes present within QTL confidence intervals revealed many potential candidate genes such as laccase, Calvin cycle protein, serine threonine protein kinase, heat shock protein, and WRKY protein with are plying an important role with respect to drought resistance1. Marker-assisted back-crossing (MABC) and gene pyramiding programme was conducted to improve the root morphological traits and thereby drought tolerance, of the Indian upland rice variety, Kalinga III3. Phenotyping for root traits provides an opportunity for integrating root traits in crop improvement programmes, which includes destructive and non-destructive methods of root sampling. The efficiency of root phenotyping and assessment of genetic variation for root traits can be harnessed through genomic tools.

Molecular marker systems provide a reliable tool for selection of root traits. Incorporating genomic tools in plant breeding can increase genetic gains for root traits by increasing selection efficiency and minimizing the confounding effect of the environment, thereby helping in development of drought resistant crop varieties.

References:

1. BHATTARAI, U. AND SUBUDHI, P.K., 2018, Identification of drought responsive QTLs during vegetative growth stage of rice using a saturated GBS-based SNP linkage map. Euphytica, 214(2):38.

2. MATHEW, I. AND SHIMELIS, H., 2022, Genetic analyses of root traits: Implications for environmental adaptation and new variety development: A review. Plant Breed., 141(6):695-718.

3. STEELE, K.A., PRICE, A.H., SHASHIDHAR, H.E. AND WITCOMBE, J.R., 2006, Marker-assisted selection to introgress rice QTLs controlling root traits into an Indian upland rice variety. Theor. Appl.Genet., 112:208-221.