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Major breeding objectives. Monoembryonic mango cultivars are propagated by grafting onto seedling rootstocks. In many countries, uniform nucellar seedlings from polyembryonic mango are utilized as rootstocks, although this is less common in India. Polyembryonic mango cultivars are grafted only rarely. Ideally, rootstocks can confer resistance to adverse soil conditions and can affect vigour of the scion. Therefore, superior rootstocks should have certain characteristics (Iyer and Degani, 1998): (i) polyembryony for uniformity; (ii) dwarfing; (iii) tolerance of calcareous soils; (iv) tolerance of soilborne pathogens; and (v) scion compatibility.

BREEDING ACCOMPLISHMENTS. Israel has had the only mango rootstock breeding programme; however, none of the selections, neither monoembryonic nor polyembryonic, are better than the existing ‘13-1’ polyembryonic rootstock that is currently in use (Lavi et al., 1993). In Spain, a selection of local polyembryonic rootstocks from La Gomera island in the Canaries has resulted in the release of several rootstocks (mainly ‘Gomera 1’ and ‘Gomera 3’) (Galán Saúco, 2009).