Flowering time manipulation

Research in the Netherlands has involved exposing numerous clones to varying photoperiods and temperature conditions. Artificially shortening day length can induce flowering and therefore the production of seed. Mesken (1988) reported that  

It was concluded that late-maturing clones should be given an 11-hour short-day treatment for 4 weeks. This induced nearly all the clones tested to flower in time to produce adequate pollen for crossing purposes (Mesken, 1988). To make crosses, pollen from the male parent is collected in a paper bag and pollination is carried out by hand using a small brush (Mesken, 1988). 

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Giliberto L, Perrotta G, Pallara P, Weller JL, Fraser PD, Bramley PM, Fiore A, Tavazza M, Giuliano G (2005) Manipulation of the blue light photoreceptor cryptochrome 2 in tomato affects vegetative development, flowering time, and fruit antioxidant content. Plant Physiol 137 199-208... 

Very simply, the "Sea Of Green" process begins by cutting a clone from the mother plant, and then placing it in the proper medium. The rooted clones are grown for a desired time, and are then forced to flower or mature to a certain stage by manipulating their photoperiod. 

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