Milestones in Biology, Genetics, and Breeding of Pearl Millet

Pearl millet is a fascinating species for conducting basic research in biology and genetics; and for applied research in breeding. With a small number of large somatic chromosomes, pearl millet lends itself to investigation in classical and molecular cytogenetics. Its short life cycle, protogynous flowers and ability to set a large number of seeds per panicle make pearl millet highly suitable for studying flow of genes between cultivated annual species and related wild species. Centre of origin, domestication, primary and secondary gene pools of pearl millet helped in selection of suitable geographical area for collecting unique and diverse germplasm resources. The outcrossing nature of pearl millet provided the basis of exploitation of heterosis at commercial scale. Another important discovery related to pollination of pearl millet was role of pollen in reducing the infection of ovary by pathogens of ergot and smut. Knowledge of photoperiod response helped in extending the crop cultivation in new seasons and geographical regions; in controlling flowering in order to facilitate hybridization; and in selecting suitable sites for offseason nurseries. Outcrossing rate of above 85%, ease of inbred development, discovery of cytoplasmic male sterility and fertility restorer genes, lack of any negative association of cytoplasmic male sterility with growth and development, diseases and insect-pests, expression of positive and high magnitude of heterosis in productivity of hybrids and economic seed production provided a perfect platform for commercial exploitation of heterosis in pearl millet for the benefit of farming community. The genome of a reference genotype Tift 23D2B1-P1-P5 has been reported to contain an estimated 38,579 genes. Thus, a good understanding of biology and genetics of pearl millet has helped tremendously in breeding for higher productivity and stability.