ADVENTIVE EMBRYONY IN PEAR¹

The micropylar half of developing ovules of ‘Old Home’, ‘Sodak’, and New Jersey #1 pear (Pyrus sp.) collected on 4 consecutive weeks (24 June, and 1, 7, 14 July) were separated into seed coat, embryo, and gelled endosperm + nucellus and aseptically cultured on basal medium consisting of MS salts and the following additional substances in mg/liter: myo-inositol, 100; sucrose, 30,000; casein hydrolysate, 1,000; nicotinic acid, 0.5; pyridoxine· HCl, 0.5; thiamine· HCl, 0.1; glycine, 2.0; and Bacti-agar, 8,000 plus deproteinized coconut water at either 0, 10 or 20%. Cultures were maintained in 16 hours of daily illumination at 1.5 klx from Cool White fluorescent lamps and at a constant temperature of 26°C. A total of 272 of 323 zygotic embryos showed abnormal proliferation (including extra cotyledonary structures, extra hypocotyl, and outgrowths or protuberances) but no similar development occurred in seed coats.
One adventive embryo developed from 452 explants of endosperm + nucellar tissue (‘Old Home’ collected 7 July and cultured without coconut water) but subsequent development was incomplete.

III International Symposium on Pear Growing

J. Janick

https://doi.org/10.17660/ActaHortic.1982.124.5