A review on Perennial fruits Seed production potential enhancement by using apomixes

Abstract

Globalization of agriculture is increasingly calling for improved efficiency and competitiveness of the existing production systems. Plants reproduce in different methods. Sexual reproduction of fruit trees is a rarely used method in horticulture. Mainly applied in research stations to conserve the richness of the gene pool and develop new varieties. On the production side, this method cannot satisfy the requirements for production quality and quantity. In other case plant can be asexually reproduced either by using part of two or more plants in a union or parts of the same plant which in the case of grafts age and in the rooting. All asexual propagation techniques belong one of the two categories. Seeds formed by apomixis have maternal genotype because their embryo is derived from that have not undergone of meiosis and fertilization that define sexual embryo development. Absence of meiotic process and paternal contribution to the embryo genotype do mean that apomixis offers a clonally propagating method of plants through seeds. As in most fruit tree species, walnut tree is a heterozygous plant, therefore the most certain way to get uniform plantations, with higher quality cultivars, is vegetative propagation. Vegetative propagation in walnut tree by grafting is still a difficult method that involves higher expenses. The most methods include Root Cuttings, Softwood cuttings, Hardwood cuttings, vegetative propagation by bud grafting or budding, Vegetative Propagation by grafting. Fruit formation by apomixy theoretical and practical significance; the embryo, being homozygous, is transmitting the similar characteristics of plant. (NICULINA, 2011). One of the most important prerequisites for genetic manipulation of plants in vitro is the ability to grow somatic cells in sterile plant growth medium and to regenerate viable plants from these cultures. Somatic embryogenesis, therefore, is a more efficient pathway for studies involving production of genetically transformed plants.(Kamle et al., 2011).