Pearl millet [ Pennisetum glaucum (L.) R. Br.] is one of the world's hardiest warm-season cereal crop and is cultivated mainly in the semi-arid tropics of Asia and Africa for food, feed, fodder, and brewing. It is mainly cultivated for its gluten-free grains with high content and better quality of nutrients. Pearl millet is a resilient crop that can produce grain and biomass under harsh conditions like low fertility, erratic rainfall, acidic and saline soils, and the hottest climates. However, biotic stresses such as downy mildew and blast diseases and abiotic stresses, especially drought and seedling- and flowering-stage heat stress, pose constant threat to the realization of yield potential of this crop. To make further improvement in threshold level of abiotic and biotic stress tolerance, breeders are looking for novel genes in diverse germplasm sources. Crop wild relatives (CWRs) could be a source of novel genes that are important for diversification of the genetic base of pearl millet. A stage-gate process is proposed for the efficient management of prebreeding programs using CWRs as a source of germplasm diversity and improvement. This article explains the various strategies for capturing and using alleles for climate resilience traits improvement. This article covers breeders’ perspectives on importance of using CWRs as germplasm source for crop improvement. This article also describes the availability of CWRs, characterization of new traits and the strategies to be applied for the identification and introduction of genes of interest in elite breeding lines and commercial varieties and hybrids of pearl millet.

Climate change is affecting agricultural production in the coastal areas of the Mekong Delta through the intrusion of salinity into the rice ( Oryza spp.) fields, where farmers cultivate photoperiod-sensitive rice varieties with long growth duration and low grain yields. A set of 12 stable crop wild relative (CWR)-derived rice lines with introgressions from wild rice Oryza rufipogon Griffiths and O. nivara S.D. Sharma & Shastry was evaluated for their phenotypic response to salinity tolerance by a participatory selection approach on farm in the Phuoc Long and Gia Rai districts, Bac Lieu province. The evaluation of the results showed that four lines derived from CWR are well adapted to the local environmental conditions, with high grain yield (>6.5 t ha −1 ), early maturity, and short plant height. These CWR-derived lines were adopted by farmers and proposed for testing on a larger scale in different areas of the coastal zone.

Breeding for salt tolerance or abiotic stress, in general, requires rapid but reliable screening protocols that reflect the actual field situation as much as possible. A collection of 200 crop wild relative (CWR)-derived BC 3 F 3-4 rice ( Oryza sativa L.) lines developed at the International Rice Research Institute (IRRI) were evaluated by farmers in the Mekong Delta over two seasons for agronomic performance. Fifty stable BC 3 F 5 lines were selected and subsequently screened in hydroponics using three NaCl concentrations to assess their phenotypic response to salt stress. The lines and check varieties were grown in a salinized Yoshida nutrient solution at three concentrations: 68, 102, and 13 mM NaCl. Several lines were identified to be tolerant to salinity stress and ANOVA showed significant differences among genotypes and NaCl concentrations. Root and shoot growth parameters showed an inverse relationship with increasing NaCl concentration. Population genetic analysis suggested four groups of genotypes, where the median salt injury score across the three NaCl concentrations was identified as the main clustering factor. Lines from Cluster 3 were identified as the most promising donors of salt tolerance.

Changing climates and associated increased variability pose risks to alfalfa ( Medicago sativa L.) cultivation, with the requirement to establish, survive, and maintain production under water stress. Crop wild relatives (CWR) of alfalfa include populations that have evolved to survive in a number of different, extreme environments, but until recently have had limited use in breeding programs. Here we report on the phenotypic diversity of alfalfa crop wild relatives that were selected to represent extremes in drought tolerance (by sourcing germplasm from environments with extremes in low rainfall, high temperature, shallow soils, and winter freezing) with the aim of providing germplasm with drought tolerance and improved forage yield traits for breeding programs in both warm and cool dry temperate environments. Newly formed hybrids created between M. sativa , M. arborea L. (a woody shrub), and M. truncatula Gaertn. (an annual species from the Mediterranean region) were developed or acquired to introduce new genetic diversity from the tertiary genepool. Preliminary characterization and evaluation was used for taxonomic classification, and to identify wild accessions and pre-bred (hybrid) lines that offer new diversity for growth habit, seed size, fall dormancy, and forage yield. The accessions and pre-breeding lines described have been donated to the Australian Pastures Genebank for conservation and distribution.

Plant domestication and crop improvement have resulted in reduced genetic diversity in most of our cultivated crops, thus limiting their potential to adapt to future challenges (Byrne et al., 2018; Keneni, Bekele, Imtiaz, & Dagne, 2012; Tanksley & McCouch, 1997; Swarup et al., 2021). One response to mitigate the impact of climate change on agricultural systems is to develop improved varieties that are genetically tolerant or resistant to the new range of abiotic and biotic challenges. Improvement via crop breeding requires access to novel variants of genes for complex adaptive traits. Crop wild relatives (CWR) and landraces are a potentially valuable source of these alleles (Cossani & Reynolds, 2015; Seiler, QiL, & Marek, 2017). However, these materials are often difficult to work with and require genetic selection to make them agronomic and useful in a breeding program, a process commonly referred to as ‘pre-breeding’. This term was first used by Rick (1984) and refers to a wide range of activities designed to (i) identify beneficial traits in CWR and other plant genetic resources (PGR), and (ii) transfer these traits into breeding lines (Ortiz, 2002; Sharma, Upadhyaya, Varshney, & Gowda, 2013). Pre-breeding forms a bridge between the genebanks that hold and safeguard CWR and landraces, and breeders and farmers who use them.