**10. Plant breeding and molecular approaches for underutilized grasses promotion**

Plant breeding is a set of scientifically driven procedures and techniques for developing new genotypes through process called crop improvement, cultivar development and seed improvement. It assists to create multi-generations of genetically diverse populations generally through human triggered selection for creating the

adapted plants having new combinations of desirable traits. There is an urgent need of developing the grass species having potential to yield higher under rapidly changing climate scenarios. This can be achieved by imparting traits of tolerance against abiotic and biotic stresses in order to fulfill the rising demands of food for rapidly growing populations. In the mid era of twentieth century, conventional breeding methods of plants had resulted in the historical green revolution since very high yielding crop varieties were produced by breeders. However, now under the scenario of climate change, conventional methods of breeding plant species are not sufficient. Molecular tools and techniques have evolved for developing plant-species with enhanced nutritional value through direct transfer of desirable genes controlling the demanded traits. Genetically engineered or modified crops, conventionally named the geneticallymodified-crops (GMOs) can effectively supplement the conventional methods for producing improved quality plants for food and feed. Crop-species can be developed by genetic engineering for enhanced yield, nutritional qualities as well as the enhanced resistance to different environmental stresses. Breeding strategies for improved forage species is different from major crops since it requires a long-duration and demands the integrated use of the other disciplines such as; genetics, breeding, biotechnology, agronomy, entomology, physiology, pathology and animal-nutrition [34].

Breeding programs for underutilized grass species require complete knowledge of species-genetic-relationship, chromosomal composition, polyploidy and the, degree of existing gene-recombination or genetic variation for further selection and hybridization. Hence, the overall strategy differs among the species. However, a remarkable progress in the areas of modern molecular gene engineering tools has opened new horizons. Molecular approaches using biotechnological tools to produce improved forage crop varieties were started in the late-eighties. Such biotechnological tools include: Molecular techniques to observe the genetic composition, foreign or distantgene insertion directly into the targeted plant-genome, and micro propagation from single cells in vitro. Various other such techniques such as embryo rescue, haploid plant production and creation of new variations aid in different steps involved conventional breeding methods consequently minimizing time required for conventional breeding methods. Additionally, the plants bred through such techniques do not conflict with the interests of the individuals who oppose the genetically -modified -organisms. For production of hybrids of Lolium-Festuca, the embryo-rescue technique has been exploited efficiently. There are several classic techniques of molecular breeding viz.; restriction-fragment-length polymorphism (RFLP), random amplified polymorphic DNA (RAPD), amplified- fragment-length polymorphism (AFLP), and isozymes which are frequently exploited for characterization of germplasm, quality trait loci (QTL) identification, detection of hybrids, cultivar identification, gene tagging, and genetic mapping. The molecular characterization of the genetic structure of forage crops as well as weeds is equally important. Since, if the gene identified from one plant species or living-organism contains the similarity in its sequence offers ease in its transfer into the target species through gene transformation [35].

Although, characterization of available germplasm is crucial particularly under the changing climates scenario, the gene-tagging and genetic-mapping in forage species is much lagging behind. For traits which are under the control of a single gene, gene tagging is essential, but in the case of forages most of the desirable agronomic traits are under the control of many genes and are thus very difficult to tag. Gene identification for the genes controlling apomixes in grass-breeding is a key to produce hybrid seed of underutilized grass species. Cloning and functional identification of these genes can be patented by breeder and can also be used for fixing heterosis in various species and offers time saving for hybrid seed production each year. Famous example is the Napier x Bajra hybrid, which was produced by the cross between *Pennisetum glaucum* and *Pennisetum purpureum*.

Recent progresses in the areas of genomics complemented with high-throughput and precision phenotyping facilitate the identification of genes controlling economic agronomic traits. The detection of these genes can be combined with genome editing techniques for the speedy development of climate change resilient plant species. Currently, genome editing is applied in major food crops and this technique has the potential for rapid improvement of underutilized crop plants, specially, targeting the current and future challenges of climate change. The success of genomics in improving a given plant species is also influenced by the nature of the trait under study. For example, traits intensely affected by the environment and genotypic and the environmental interaction are more challenging to study and modify [36]. Another approach could be intercropping underutilized grasses with staple cereals and legumes as this approach has the potential to boost soil fertility, total yield, and economic turnouts along with numerous other ecological benefits such as improvement in soil microbial population [37–40].

Transgenic technology allows the transfer of foreign genes from unrelated species and thus offers enormous scope to improve underutilized grass species. The development of more detailed gene maps of different species, using genomics and allied molecular tools will help in the identification of genes or gene sequences that might be associated with responses to changing climate stress. Although the biosafety and health hazards linked with GM crops have been questioned, a number of crop species have already been genetically-engineered and carefully tested and possess no obvious risk. Integrated use of modern biotechnology, with conventional agricultural in a sustainable way, can lead to achieving the ultimate goal of achieving food security for current and future populations. Transgenic approaches have been employed to improve these species in the following aspects: significant improvement of dry matter digestibility in the case of tall fescue, alfalfa, and perennial ryegrass. By efficient integration of novel germplasm into practical breeding programs, transgenic cultivars offer the potential to play a potential role in fulfilling the growing demand for animal products as well as renewable fuels in the coming years.
