The use of wild relatives in crop improvement: a survey of developments over the last 20 years

Abstract

The use of crop wild relatives (CWR) genes to improve crop performance is well established with important examples dating back more than 60 years. In this paper, we review available information on the presence of genes from CWR in released cultivars of 16 mandate crops of the CGIAR institutes, and some selected additional crops, focusing on the past 20 years-the period since a comprehensive review by Robert and Christine Prescott-Allen in 1986. It appears that there has been a steady increase in the rate of release of cultivars containing genes from CWR. While there continues to be a strong emphasis on using pest and disease resistance genes, a wider range of characteristics are being introduced than in the past. Those crops whose wild relatives have traditionally been used as sources of useful traits (e.g., wheat, tomato) continue to be most likely to include new genes from their wild relatives. CWR are continually gaining in importance and prevalence, but, we argue, their contributions to the development of new cultivars remain less than might have been expected given improved procedures for intercrossing species from different gene pools, advances in molecular methods for managing backcrossing programes, increased numbers of wild species accessions in gene banks, and the substantial literature on beneficial traits associated with wild relatives.

Capturing genetic variation in crop wild relatives: An evolutionary approach

“…Plant breeders exploit this wild diversity through a variety of traditional and modern genomic means, but generally seek to enhance or restore adaptive traits lost or degraded over the course of crop domestication. Commonly targeted genes and traits include those which underpin crop resistance to pests and disease, but have also included abiotic stress, yield and quality related traits (Dwivedi et al., 2008; Hajjar & Hodgkin, 2007; Maxted & Kell, 2009; Vincent et al., 2013). Such exploitation of CWRs in crop improvement programmes has grown steadily since the middle of the last century (Heywood, Casas, Ford‐Lloyd, Kell, & Maxted, 2007; Maxted & Kell, 2009).…”

“…Accordingly, it has previously been estimated that about 30% of gains in crop yield worldwide—corresponding to an annual value of US $151 billion—could be attributed to the incorporated use of CWR germplasm (Pimentel et al., 1997). Furthermore, the frequency of release of cultivars containing CWR genes is set to further increase into the future (Dempewolf et al., 2017; Hajjar & Hodgkin, 2007; Lane & Jarvis, 2007), highlighting the renewed role for research in helping to meet this demand.…”

Climate change and crop diversity: farmers’ perceptions and adaptation on the Bolivian Altiplano

“…Gene flow between wild and cultivated types is an important element of crop adaptation in their centres of origin (e.g. Rodríguez et al 2010;Hufford et al 2013;Mutegi et al 2015), and the role of crop wild relatives as a source of stress tolerance and resistance traits for crop breeding is well acknowledged (Hajjar and Hodgkin 2007;Jansky et al 2013). This study also revealed the value of hardy wild relatives of quinoa, cañahua, and potato as famine foods for Altiplano communities in periods of climate stress.…”

Field characterization of endemic wild Vigna accessions collected from biodiversity hotspots of India to identify promising genotypes for multiple agronomic and adaptive traits

“…Nevertheless, their inherent yield potential is low as compared to other pulses and requires to be enhanced thorough recombination breeding. Efforts have been made to search for genes imparting yield traits and resistance to biotic and abiotic stresses within the cultivated species and to a limited extent among their wild relatives but success has been limited to a few diseases and insect pests; mostly where the genes are confined to the primary gene pool of the particular species (Knott and Dvorak, 1976;Stalker 1980;Ladizinsky et al, 1988;Prescott and Prescott, 1986;Kumar et al, 2003;Hajjar and Hodgkin 2007). The use of wild relatives as sources of new germplasm is well established in crop breeding programs in several crops, especially cereals, but the efficiency with which wild germplasm is utilized for introducing disease resistance and other agronomic characters into elite cultivars varies greatly from species to species (Bisht et al, 2005a(Bisht et al, , 2005bKumar et al, 2011).…”