Impact of biophysicochemical factors on micropropagation, haploidy and doubled haploidy in strawberry (Fragaria sp.): A critical revisit

Fragaria, commonly known as the strawberry, is one of the most economically important genera of fruit plants. Strawberries have a wide range of health-promoting and nutritious ingredients. They can be found all over the world and appeal to people due to both their flavor and appearance. Strawberries are propagated either by runners or by in vitro methods. Meristems, callus or shoot cultures of strawberries are used for in vitro propagation to increase the production- and cost- efficiency. The interaction of various physical, chemical and biological factors has been shown to have a profound effect on micropropagation. Light is one of the important physical variables that influences the growth and development of plants, especially in plant tissue culture, such as light-emitting diodes (LEDs). LED technology has proven to be advantageous for plant production in greenhouses for various purposes, including the induction of photomorphogenic responses of plants grown in vitro. Chemical and biological parameters such as media composition, growth regulators and choice of explants are also critical factors for micropropagation. This review summarizes the effects of biophysical-chemical factors on in vitro propagation as well as the production of haploids and doubled haploids (DHs). The review will also discuss the challenges associated with developing a standardized protocol for mass propagation and the production of haploids and DHs in strawberries, which will eventually help in breeding and crop improvement programs.