PERFORMANCE STUDIES ON POLYEMBRYONIC VARIETIES OF MANGIFERA INDICA L.

As early as in 1719 Van Leeuwenhoek (1) discovered more than one embryo in orange seeds (Maheshwari). In Mango, Leroy (2) reports that adventive embryony has probably been developed by the effect of one or more recessive genes and according to him the centre of origin of Mangifera indica, the Eastern India, contains monoembryonic varieties having dominant genes, while Cochin, China, the Philippines and the Sunda Islands, the secondary centres, have the varieties which have recessive genes and polyembryony. Webber (8) has reported that seeds of the polyembryonic varieties may be useful for rootstock purpose. Adventive embryos produce genetically uniform seedlings which reproduce the seed parent genotype without the variation caused by segregation in sporogenesis or by recombination in fertilization (4). The nucellar seedlings have been used as rootstocks in commercial plantations of Citrus (9). Selection of uniform rootstock is one of the burning problems; confronting the growers engaged in the mango industry (7).

A large number of polyembryonic mango varieties were introduced at the Government Horticultural Research Institute, Saharanpur, in 1954–55 from different countries namely Ceylon, Indonesia, the Philippines, Israel and Florida with a view to finding out their suitability as rootstocks for the commercial mango varieties. Plants of a few varieties came into bearing and preliminary observations regarding their performance were reported by Singh (6). Detailed studies on yield, extent of polyembryony, polyembryonic variety and fruit characters were carried out in Bappakai, Carabao, Cecil, Kurukkam, Peach, Sabre, Simmonds and Turpentine at Saharanpur.