Actions and Outcomes
Fruit development in tomato is substantially influenced by environmental changes. Since recent times, parthenocarpy has become a highly discusses issue as it provides the possibility to improve fruit productivity and quality. Environmental conditions adverse for germination, fertilization, and pollen production have a negative influence on the quality and production of fruits. Therefore, parthenocarpy is one of the most effective ways that enhance fruit production under environmental conditions adverse for fertilization and pollination. Nowadays, the development of parthenocarpic fruits is considered to be an attractive approach for both growers and consumers.
Genetic engineering of parthenocarpy provides horticultural plants with an opportunity to produce fruits under the unfavorable conditions that decrease fruit quality and productivity. The DefH9-iaaM gene has been shown to have a positive influence on several species of plants including eggplant, tomato, and others. The method of parthenocarpy enables the generation of a wider expressivity range of the desired trait in transgenic plants (Pandolfini et al., 2001).
In some crops the seed absence results in the improved fruit quality, while in others parthenocarpy improves productivity because there is no need in pollinator plants. Thus, parthenocarpy enables early fruit production and harvest, as well as improves fruit quality in the plant species (Spena & Rotino, 2001). It has been found that the parthenocarpic fruit’s pH may remain unaffected. In addition, the soluble solid concentration may be unchanged or increased. It leads to the conclusion that the DefH9-iaaM gene is a genetic tool that is able to improve tomato productivity and sustain the development of a parthenocarpic fruit in different tomato types. The research has shown that marketable fruits are often produced under environmental conditions that are considered to be adverse for fertilization and pollination. It has no adverse influence on fruit quality (Ficcadenti, 1999).
The research results have shown that the DefH9-RI-iaaM fruits were seedless or were characterized by the lack of seeds. It has become evident that the quality of genetically modified fruits does not show any chemical and technological difference when compared to control line fruits. In addition, parthenocarpic fruits, produced under open field conditions, are characterized by a substantially decreased number of seeds. Moreover, parthenocarpy that results from the DefH9-RI-iaaM gene is a representation of a tool for GM seed mitigation (Rotino et al., 2005). Evaluation of genetically modified eggplants has shown that they outyield the corresponding untransformed genotypes and improvements in eggplant productivity are also achieved in open field cultivation. The quality of eggplant fruits may be improved due to the absence of seeds. Thus, the DefH9-iaaM gene has a positive quantitative and qualitative effect on eggplant production under open field and greenhouse cultivation (Acciarri et al., 2002).
The research results have also shown that the DefH9-iaaM parthenocarpic gene increases the eggplant genotype agronomic value. The main DefH9-iaaM eggplant advantages include improved quality of seedless fruits, good quality of fruits during different cultivation types, and improved productivity of fruits under open field and greenhouse cultivation. From an economical point of view, the main advantages that an eggplant received from the DefH9-iaaM gene are fruit production under adverse environmental conditions, cultivation costs reduction, and fruit quality enhancement. These advantages may be achieved without the sterility gene use (Acciarri et al., 2002).
The parthenocarpic gene tends to have a positive impact on eggplant productivity under spring and summer cultivation. The increase in the DefH9-iaaM eggplant productivity may be explained by the improved fruit-set and enhanced fruit weight and growth. In addition, the quality of fruits is improved because of the seed absence that shows no placental cavity.
The modern techniques of plant related genetic engineering applied to the seedless fruit production have a great future potential. New strategies are based on the genetic engineering development that provides new plant improvement opportunities. Transformation of plants has enabled modification of one or two traits retaining the unique original cultivar characteristics. However, there are some transgenic application limitations that require researchers’ attention. The analyzed experiments have shown that the parthenocarpic provides a number of advantages in specific situations including different temperature, lack of quality and others.
In some species, parthenocarpic results in the absence of fertilization and absence of seeds. It indicates that there is a possibility to uncouple fruit formation from the development of seeds. Parthenocarpy is based on genetics and is selected for the programs related to seedless fruit-breeding inducing a wide range of species with the exogenous application of auxins, GAs, and cytokinins.
In addition, genetic control can enhance fruit production widening the range of grown tomato and indirectly increasing fruit productivity. In addition, genetically engineering, parthenocarpic in particular, positively influences productivity increase and indirectly reduces the cultivation cost. Some experiments were carried out in three environments that were characterized by differences in soil, temperature, kind of crossing and DefH9-iaaM control. The production of eggplants under control is substantially larger than the production of plant under natural growth. It has become evident that there is a possibility to control DefH9-iaaM. It means that people have an opportunity to guide the species a way they want them to be. This is the main contribution of genetic engineering.