Engineered Male Sterility
The agricultural exploitation of hybrid crop varieties has enabled enormous increases in food productivity through increased uniformity and hybrid vigour. Because of hybrid vigour, or heterosis , these crops are characterized by an increased resistance to
- PDF / 284,467 Bytes
- 13 Pages / 439.37 x 666.142 pts Page_size
- 50 Downloads / 214 Views
Engineered Male Sterility Frank Kempken
14.1
Introduction
The agricultural exploitation of hybrid crop varieties has enabled enormous increases in food productivity through increased uniformity and hybrid vigour. Because of hybrid vigour, or heterosis, these crops are characterized by an increased resistance to disease and enhanced performance in different environments when comparing the heterozygous hybrid progeny (called F1 hybrids) to the homozygous parents (Lefort-Buson et al. 1987). Heterotic hybrid varieties in major crops, such as cotton, maize, and rice, exhibit >20% yield advantage over conventional varieties under the same cultivation conditions. The increased vigour, uniformity, and yield of F1 hybrids has been exploited in most crops for which the pollination system allows for an economical and convenient cross hybridization (Basra 2000). In hybrid seed production, one line is designated as the female parent and the other as the male parent. The production of hybrid seeds requires a pollination control system to prevent unwanted self-pollination of the female line, which can be a great challenge, particularly for crop species with hermaphrodite flowers. Many methods exist to prevent the self-pollination of the seed parent (female line) during hybrid seed production: the application of male-specific gametocides, such as mitomycin and streptomycin (Jan and Rutger 1988); some inter- and intra-specific crosses (Hanson and Conde 1985); the mechanical removal of male flowers or anthers, chemical treatment, i.e. the patented chemical hybridising agent, Croisor, and use of genetic cytoplasmic or nucleus-encoded male sterility. Generally, naturally occurring genetically male sterile plants maintain fully normal female
F. Kempken Abteilung fu¨r Botanik mit Schwerpunkt Genetik und Molekularbiologie, Botanisches Institut und Botanischer Garten, Christian-Albrechts-Universita¨t zu Kiel, Olshausenstrasse 40, 24098 Kiel, Germany e-mail: [email protected]
F. Kempken and C. Jung (eds.), Genetic Modification of Plants, Biotechnology in Agriculture and Forestry 64, DOI 10.1007/978-3-642-02391-0_14, # Springer-Verlag Berlin Heidelberg 2010
253
254
F. Kempken
functions. The phenotypic characteristics of male sterility are diverse, including the complete absence of male organs, the abortion of pollen at any step of its development, a failure to develop normal sporogenous tissues, the absence of stamen dehiscence, or an inability of mature pollen to germinate on compatible stigma. The generation of male sterility, mainly nucleus-encoded, is the basis of new, reliable, and cost-effective pollination control systems for genetic engineering that have been developed during the past decade. The propagation of male-sterile female parent lines is an important aspect for the successful application of these systems in large-scale hybrid seed production. Engineered male sterility has also been discussed in a number of recent reviews (Khan 2005; Takada et al. 2005; Chase 2006; Stockmeyer and Kempken 2006; Pelletier and
Data Loading...
