Advancements in molecular marker technologies and their applications in diversity studies.

Crop improvement is a continuous effort, since some 10,000 years ago when primitive man made the transition from hunting and foraging to domestication and crop cultivation. Since then, man-made interventions have changed the entire scenario of crop evolution, by means of genetic alterations of plants and animals made to satisfy man's needs. The process of domestication has led to dramatic changes in their appearance, quality and productivity that have contributed substantially to global food security. The tremendous decline in cultivable land, freshwater, and increasing risk of biotic and abiotic stress demand immediate attention on crop improvement to cope with the higher demand of ∼ 40% of the food by 2020. Therefore, plant genetic variation plays a key role in plant breeding for its improvement. Most of the genetic variations useful for crop improvement have been deposited and maintained in seed gene banks across the world; they need to be brought into the mainstream of breeding lines. Recent advances and progress made in molecular markers have been substantial tools for deeper insights of genetics, and greatly complemented breeding strategies. Integration of the next-generation sequencing (NGS) technologies with precise phenotyping, association mapping, proteome and metabolome studies has increased the chances of finding candidate genes and their allelic variants controlling a trait of interest. Further, these functional markers (FMMs), genotype-by-sequencing and association mapping methodologies have opened new avenues for identification of novel genetic resources (lines) that can facilitate accelerated crop breeding programs for increased yield, high nutritional quality, and tolerance to a variety of abiotic and biotic stresses. The details of popular molecular markers, advancement in the technologies and strategies for crop diversity studies and their application in crop breeding programs are presented here.