About this Research Topic
The FAO estimates that the global demand for grains will increase by 70% until 2050. Most of the required growth in production will have to take place on existing land and despite the negative effects of climate change, a decreasing availability of ground & surface water, depleting soils and increasing fertilizer and energy costs. Unprecedented success was achieved through development of input-responsive high yielding short stature varieties during and after ‘green-revolution’ period. This major paradigm shift was mainly achieved by introducing semi-dwarfing genes into the locally adapted low yielding, low fertilizer responsive and lodging prone tall traditional varieties of wheat and rice, the lifeline crops of developing world. Green revolution in South Asia played a key role in ensuring food security through miracle varieties of rice and wheat, IR64 and PBW343 respectively. Impact of the green revolution is more seen in the irrigated areas (compared to rainfed) of South Asia as well as other parts of world. However, the current yield potential gain in staple food crops (rice, wheat, maize) is almost half than that of required meeting the global demand by 2050. This is an alarming situation emphasizing for immediate expansion of the genetic base of cultivated varieties targeting yield, stress-tolerance and nutrition as well.
In the current climate change era, apart from slow yield potential gain, multitude of stresses and demand of bio-fortified crop varieties are on cards, agricultural innovations become extremely relevant. Deployment of diverse genetic resources with the help of advanced genomics technologies can be one potential option to address this call. The on-farm diversity as well as genetic variability maintained in GeneBanks represents important reservoir for this purpose. Wild relatives of crop plants and landraces/traditional cultivars have been evolved in specific environments under particular set of climatic conditions. The value of these germplasm sets can be harnessed through using recently available advanced genomics tools. Approaches such as genomic selection, genome editing and other high density genomics applications need to be applied to efficiently utilize the diverse germplasm resources in varietal development. Such a comprehensive approach aiming for synergizing germplasm resource and genomics tools can be defined as “genomics-assisted-pre-breeding”. Several initiatives have been undertaken globally following this synergistic approach (eg. BBSRC funded WISP project, CIMMYT’s- ‘Seeds of discovery’ project etc.). Capturing under-utilized genetic diversity, identifying new sources of variations or novel genes/alleles need to be pursued through following above mentioned synergies. This will enable broadening of genetic base of cultivated crop varieties, incorporating useful alleles to breeding pipelines as well as harnessing the value of rare allelic variations which is still a bottleneck for conventional plant breeders. Pre breeding is a broad term refers to all pre-requisites of crop varietal improvement programs including:
(1) Diversity analysis
(2) Functional genomics-GWAS, GS, linkage mapping etc.
(3) Structural genomics- allele mining, gene editing etc and
(4) Other possible approaches/methods.
Harnessing crop biodiversity through “genomics-assisted-pre-breeding” is the felt need of breeders world-wide. Philosophically, “Looking beyond Green Revolution is in fact looking behind the Green Revolution”.
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