In Vitro Selection of Disease-Resistant Plants

Worldwide crops are attacked by several diseases, and due to these diseases, heavy loss in the yield of crop plants is a common phenomenon. This is more common in tropical regions. Diseases affect plants during all stages of their life cycle and even during storage stage. Controlling the pathogens through chemical pesticides is a very costly affair and labor intensive (Bezier et al. 2002). In addition, they also pose environmental hazards as they are nonbiodegradable; they accumulate in the soil and reduce the production of crops. They also cause loss of local flora and fauna. Hence, it has become pertinent to find alternative biotechnological methods to develop disease-resistant crop plants. An important step in the breeding of crops is to develop an effective strategy for selection of desirable traits (Roane 1973; Van den Bulk 1991; Novak and Brunner 1992; Lebeda and Savabova 2010). Conventionally, selection of traits of interest is carried out in the field; this involves identifying resistant plants, crossing them with the superior yielding variety, and studying their inheritance pattern, which may require 12–15 years to release a new variety. Compared with the techniques of in vitro selection (Novak and Brunner 1992; Jin 2001; Patade et al. 2008). Genetic engineering is another approach that can be utilized to develop disease-resistant plants, but limitations in the form of transgene silencing (Manners and Casu 2011) reduced gene expression, and frequency of low transformation (Mondal et al. 1997) and tough legislations (Burnquist 2006) hampers the use of this approach (Table 18.1 and Plates 18.1, 18.2, and 18.3).