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The olive (Olea europaea L.) is, at the same time, one of the most ancient domesticated fruit trees and the most extensively cultivated fruit crop in the world, covering an area of about 7.5 million hectares. The recent diffusion of olive outside its traditional area of cultivation, the Mediterranean basin, together with a continuous trend in the modernisation of its industry, has greatly increased in recent years the demand for improved cultivars by olive growers. Hence, programmes of clonal selection and cross-breeding have been started in the main olive growing countries, aiming at selecting genotypes characterised by early bearing, resistance to pests and to abiotic stresses (such as frost and drought), limited alternate bearing, suitability to intensive culture and to mechanical harvesting, as well as high-quality productions, in terms of both organoleptic characteristics of fruits and oils, and high contents in substances useful for human health. This chapter reviews the recent advances in olive breeding, providing extended information on flower biology, main world cultivars, germplasm collection and preservation, propagation techniques, main characters for olive improvement and traditional breeding techniques (clonal selection, cross breeding and mutagenesis). In addition, information on the recent developments of olive biotechnology for the improvement and the safeguard of genetic resources (tissue culture, synthetic seed technology, genetic transformation and cryopreservation) is also reported.

A protocol for micropropagation of Virginia-type peanut plants, an ancient crop of the New World, is reported. This study was conducted to explore the effect of silver nitrate (AgNO3), alone or in combination with growth regulators, on multiple shoot formation from shoot tip culture. Incorporation of AgNO3 into the medium, without growth regulators, induced regeneration of the explants (which did not develop at all in the AgNO3-free medium), and stimulated the emergence of axillary shoots. When AgNO3 was added in combination with cytokinins and α-naphthaleneacetic acid (NAA), maximum average shoot number per regenerating explant was recorded (6.3) in Murashige and Skoog (MS) medium containing 33 μM 6-benzyladenine, 5.3 μM NAA, and 23.54 μM AgNO3. Moreover, AgNO3 showed a positive and marked effect on both shoot elongation and the reduction of callus proliferation from the basal ends of shoot tips. Following a period of elongation, the shoots were rooted in hormone-free Ms medium, showing no residual effects due to the long-term culture in AgNO3-containing media. Acclimatization was easily obtained after plantlets were transferred to pots under greenhouse conditions, with 90% survival.