Apomixis for crop improvement

Apomixis is a genetically controlled reproductive process by which embryos and seeds develop in the ovule without female meiosis and egg cell fertiliz ation. Apomixis produces seed progeny that are exact replicas of the mother plant. The major advantage of apomixis over sexual reproduction is the pos sibility to select individuals with desirable gene combinations and to prop agate them as clones. In contrast to clonal propagation through somatic emb ryogenesis or in vitro shoot multiplication, apomixis avoids the need for c ostly processes, such as the production of artificial seeds and tissue cult ure. It simplifies the processes of commercial hybrid and cultivar producti on and enables a large-scale seed production economically in both seed- and vegetatively propagated crops. In vegetatively reproduced plants (e.g., po tato), the main applications of apomixis are the avoidance of phytosanitary threats and the spanning of unfavorable seasons. Because of its potential for crop improvement and global agricultural production, apomixis is now re ceiving increasing attention from bath scientific and industrial sectors. H arnessing apomixis is a major goal in applied plant genetic engineering. In this regard, efforts are focused on genetic and breeding strategies in var ious plant species, combined with molecular methods to analyze apomictic an d sexual modes of reproduction and to identify keg regulatory genes and mec hanisms underlying these processes. Also, investigations on the components of apomixis, i.e., apomeiosis, parthenogenesis, and endosperm development w ithout fertilization, genetic screens for apomictic mutants and transgenic approaches to modify sexual reproduction by using various regulatory genes are receiving a major effort. These can open new avenues for the transfer o f the apomixis trait to important crop species and will have far-reaching p otentials in crop improvement regarding agricultural production and the qua lity of the products.