Crop Wild Relatives: A Valuable Source of Tolerance to Various Abiotic Stresses

Abstract

Global climate change is one of the major constraints limiting plant growth, production, and sustainability worldwide. Moreover, breeding efforts of the past years have focused on improving certain favorable crop traits, leading to genetic bottlenecks. The use of crop wild relatives (CWRs) to expand genetic diversity and improve crop adaptability seems to be a promising and sustainable approach for crop improvement in the context of the ongoing climate challenges. In this review, we present the progress that has been achieved towards CWRs exploitation for enhanced resilience against major abiotic stressors (e.g., water deficiency, increased salinity, and extreme temperatures) in crops of high nutritional and economic value, such as tomato, legumes, and several woody perennial crops. The advances in -omics technologies have facilitated the elucidation of the molecular mechanisms that may underlie abiotic stress tolerance. Comparative analyses of whole genome sequencing (WGS) and transcriptomic profiling (RNA-seq) data between crops and their wild relative counterparts have unraveled important information with respect to the molecular basis of tolerance to abiotic stressors. These studies have uncovered genomic regions, specific stress-responsive genes, gene networks, and biochemical pathways associated with resilience to adverse conditions, such as heat, cold, drought, and salinity, and provide useful tools for the development of molecular markers to be used in breeding programs. CWRs constitute a highly valuable resource of genetic diversity, and by exploiting the full potential of this extended allele pool, new traits conferring abiotic-stress tolerance may be introgressed into cultivated varieties leading to superior and resilient genotypes. Future breeding programs may greatly benefit from CWRs utilization for overcoming crop production challenges arising from extreme environmental conditions.

Cowpea Constraints and Breeding in Europe

“…Crop wild relatives of cowpea were assessed leading to the identification of high levels of abiotic stress tolerance, however efforts proved fruitless due to failure of crossing [ 204 ]. Numerous genotypes and accessions, including landraces, have been therefore characterized and evaluated with the goal of being a genetic resource for drought, heat and salinity tolerance [ 180 , 205 , 206 , 207 , 208 , 209 , 210 , 211 , 212 , 213 , 214 ].…”

Utilization of crop wild relatives for biotic and abiotic stress management in Indian mustard [Brassica juncea (L.) Czern. & Coss.]

“…Studies related to use of CWRs for identification of stress resistance traits and their introgression into B. juncea Gill et al, 2012;Singh et al, 2021b). Genetic diversity available among CWRs could be a useful resource for introgression of these abiotic stress resilience traits into high yielding cultivars of Indian mustard (Kapazoglou et al, 2023;Kashyap et al, 2023).…”

“…In the context of global climate change, CWRs could be promising genetic resources of abiotic and biotic stress resistance (Kapazoglou et al, 2023). In the recent past, successful breeding Abiotic and biotic stress tolerance traits associated with S. alba and protocol for generation of inter-generic hybrids of B. juncea and S. alba using ovary culture and embryo rescue technique.…”

Inbreeding depression leads to reduced fitness in declining populations of wild maize

“…Similar trends have been observed in common bean and soybean with a ∼10-72% and 36% reduction of genetic diversity in each crop respectively versus their wild progenitors (Kwak and Gepts, 2009; Bitocchi, 2013; Lam, 2010). At least a portion of the diversity retained in CWRs and lost in crops could provide useful adaptations for crop improvement (Bohra, 2022; Kapazoglou, 2023; Renzi, 2022). Already, CWRs have meaningfully contributed to breeding programs (Kashyap, 2022; Tirnaz, 2022).…”