Hidden potential of Crop Wild Relatives (CWR)
Authors: Padmavati G. Gore and Dr. Kuldeep Tripathi

Increasing population and changing climate, both become evils to nature. To feed increasing hungry and malnourished people, demand for food both in terms of quantity and quality are growing day by day. To meet this demand we need to increase yield of staple crops and increase number of crops in our food basket. But yield of most of the crops reached to at one level of plateau due to utilization of all the gene of cultivated species in traditional and modern breeding practices. To break this yield plateau search for new gene is become very essential and for new gene we really need to understand the importance of plant genetic resources.

What is a plant genetic resource?

International Undertaking on Plant Genetic Resources (FAO.1983) defines PGR as the reproductive or vegetative propagating material of i) cultivated varieties in current use and newly developed varieties; ii) obsolete cultivars’ iii) landraces; iv) wild and weed species, near relatives of cultivated varieties; v)special genetic stocks including elite and current breeder’s lines and mutants). Plant genetic resources include all our agricultural crops and their wild relatives because they possess valuable traits. Thus Crop Wild Relatives are a key component of plant genetic resources for food and agriculture.

What is CWR-?

In general terms, a crop wild relative (CWR) may be defined as a wild plant species that is more or less closely related to a particular crop and to which it may contribute genetic material, but unlike the crop species has not been domesticated. Relationship of CWR and crop species can be described by two ways, genecological – based on the extent to which they can exchange genes with the crop and taxonomic – based on their taxonomic relationship with the crop. The genecological approach often use gene pool concept of Harlan and de wet. Harlan and de Wet (1971) defines gene pool concept Of CWR to describe the degree of relatedness between wild species and cultivated species which depends on the relative ease with which genes can be transferred from wild species to crop species. Gene pool concept of CWR divides in to three types, i) Primary gene pool (GP1) contains close relatives that readily intercross with the crop Secondary gene pool (GP2) Contains all the biological species that can be crossed with the crop but where hybrids are usually sterile Tertiary gene pool (GP3) Comprises those species that can be crossed with the crop only with difficulty and where gene transfer is usually only possible with radical techniques.

Importance of CWR

To combat climate change and to meet increasing demand for food and nutrition we have to move towards crop improvement and the key to the successful crop improvement is genetic diversity of crop plant. To undertake any crop improvement programme we need continued supply of genetic variability, to fulfill all this requirements CWR Of crop species is the only answer. CWR are critical source of gene for different traits viz., gene for biotic stresses like disease and pest resistance, gene for tolerance of abiotic stresses like drought, water stress, salt salinity and extreme temperatures. Dwarfing gene in rice and wheat in wild relatives drastically changed the world of agriculture

Example- The use of wild relatives has led to improved resistance to wheat curl mite, to late blight in potato and to grassy stunt disease in rice. They have been used to improve tolerance of drought in wheat and acid sulphate soils in rice. Wild relatives have also been used to raise the nutritional value of some crops, including protein content in durum wheat, calcium content in potatoes and provitamin A in tomato. Hidden hunger due to micronutrient deficiencies is the one of the most serious problem, with which most of the countries trying to tackle. Rely on one or few crops for nutrient requirement enhance this problem, to solve this use of diversity of wild species is become need of the hour. Wild foods from the forests, provides all types of necessary micronutrients, ranging from vitamin A, vitamin C, iron zinc.

Common nutritional deficiencies, the related health problems and the potential role of wild foods: International Expert Consultation on Non-Wood Forest Products. FAO 1995.

Nutrient deficiency Related health problems Wild food sources to combat deficiency
Protein–energy malnutrition Reduced growth, susceptibility to infections, changes in skin, hair and mental ability Energy-rich food, such as nuts, seeds, oil-rich fruit and tubers and wild animals such as snails
Vitamin A deficiency Impaired vision and immune function, blindness and death in extreme cases Forest leaves and fruits, palm oil, bee larvae and other animal foods
Zinc deficiency Slowed growth and development, complications in pregnancy certain types of nuts, including pine nuts, pecans and brazil nuts
Iron deficiency Anaemia, weakness and increased susceptibility to disease mushrooms, forest leaves, baobab fruit pulp
Folate deficiency Anaemia, neural tube defects Leafy and other vegetables and many fruits
Vitamin C deficiency Increased susceptibility to disease and impaired iron status Forest fruits and leaves
Most of the CWR are not cross compatible with cultivated species to transfer the useful gene from them to crop species, but modern and innovative biotechnology tools are ready to tackle this entire problem and to make effective use of wild species in crop improvement. So to sustainable agriculture and livelihood we have to conserve our Crop Wild Relative.

About Author / Additional Info:
Currently we both working as scientist in ICAR-NBPGR.