Floral Biology, Pollination, Genetics, Origin and Diversity in Little Millet (Panicum sumatrense L. Roth ex. Roem. and Schultz)

Little millet was domesticated in India 5000 years ago. Little millet is a domesticated variety of the weed Panicum silopodium. Little millet is a tetraploid (2n = 4x = 36) plant in the Poaceae family. The chromosomes of hybrids of Panicum sumatrense and Psilopodium pair fairly completely with only one quadrivalent, demonstrating the two species divergence. Little millet is divided into two races based on panicle morphology, nana and robusta, each with two subraces (laxa and erecta for nana and laxa and compacta for robusta). This crop’s flowering is of the chasmogamous variety, in which pollination occurs earlier than flower opening. Each spikelet consists of two-minute flowers. The lower is sterile, while the top is fertile or bisexual but lacks rachilla extension. Due to this, the self-pollination has a significant advantage. Hybridization is thus a requirement for the creation of variety. Emasculation is required for crossing due to self-pollination and the lack of male sterility. In little millet crop, numerous emasculation and crossing procedures are used, including the touch method, hot water treatment, hand emasculation and the USSR method. However, the problem with these procedures is that it causes stigma harm, which diminishes the success rate of obtaining actual F1s. To alleviate all of the shortcomings of previous methods, the modified crossing ‘SMUASB’ method was recently employed. Cold water (5–8 °C) is sprayed on the panicle as a mechanical stimulator for the opening of florets in male and female panicles in this approach. Female panicle is gently rinsed in cold water for emasculation. This has no effect on stigma or its sensitivity. Before pollination, all fertilised florets and unopened immature florets are removed. As a result, the success rate in little millet using the SMUASB approach was increased, producing actual F1 with more space and fewer resources for F1 evaluation.