The experimental induction of androgenesis in tomato plants via anther culture was first reported by Gresshoff and Doy in 1972. This breakthrough followed the foundational discovery of microspore-derived haploid production by Guha and Maheshwari in 1964. Anther culture is a vital biotechnological tool in plant breeding, allowing for the rapid development of homozygous lines by doubling the chromosome number of haploid plants.

Callus is an undifferentiated mass of parenchyma cells that develops from plant tissue explants when cultured on a nutrient medium containing appropriate plant growth regulators. It is a fundamental stage in plant tissue culture used for regeneration and genetic transformation.

Synthetic seeds, or artificial seeds, are produced by encapsulating somatic embryos in a protective gel matrix. Abscisic acid (ABA) is frequently added to the encapsulation medium to inhibit precocious germination of the somatic embryos, effectively inducing a state of dormancy similar to that found in natural seeds. This allows for better storage and handling of the synthetic seeds until they are ready for germination.

The somatic hybrid known as 'Pomato' (or 'Topato') was successfully produced through the fusion of potato and tomato protoplasts. This landmark achievement in plant biotechnology was reported by Melchers, Sacristán, and Holder in 1978, demonstrating the potential of somatic hybridization to create novel intergeneric hybrids that cannot be produced through traditional sexual crossing.

Micrografting is a specialized tissue culture technique used to produce virus-free plants. By grafting a small shoot tip (meristem) onto a healthy, in vitro-grown rootstock, growers can bypass systemic viral infections that often persist in the parent plant. This method is particularly valuable for citrus and other fruit crops where maintaining disease-free germplasm is essential for commercial production and international trade.

Embryo culture is a vital in vitro technique used to cultivate embryos under sterile conditions on nutrient media. Its most significant application is overcoming hybridization barriers, such as embryo abortion in wide crosses, which prevents the development of viable seeds. By rescuing the embryo, breeders can successfully produce hybrid plants that would otherwise be impossible to obtain through conventional breeding methods, while also reducing the time required for seed germination.

Meristem culture is the standard method for eliminating viruses from infected plants. Because the apical meristematic region of a plant often has a high rate of cell division and lacks a well-developed vascular system, viruses are frequently unable to invade this tissue. By excising and culturing the meristem tip, researchers can regenerate healthy, virus-free plants from infected stock.

Cellular totipotency refers to the ability of a single plant cell to divide and differentiate into all the specialized cells required to form a complete, mature organism. F.C. Steward provided the landmark experimental proof of this concept in the 1950s by successfully regenerating whole carrot plants from isolated phloem cells cultured in a nutrient medium. This discovery laid the foundation for modern plant tissue culture and biotechnology.

The process of using plant roots to produce specific pharmaceutical compounds is typically referred to as 'hairy root culture' or 'rhizosecretion' in biotechnology. Since none of the provided options accurately describe this specific biotechnological technique, 'None of these' is the correct choice based on the provided key.

Totipotency is the ability of a single cell to divide and produce all the differentiated cells in an organism, including extraembryonic tissues. This concept is fundamental to plant tissue culture, allowing a single cell to be cultured into a complete plant. Gottlieb Haberlandt, recognized as the father of plant tissue culture, first proposed this potential. Totipotent cells are typically found in spores and zygotes.