There are a great many hindrances, biological, political and economic.

One of the biological hindrances is that it is difficult to predict what a particular genetic modification will do. Everything on the market now has a very simple mode of action, and the concept for them was proved in the 1980s. The classic FlavrSavr tomato was intended to maintain firmness to allow shipping riper fruit. In practice, the gene ended up keeping over-mature fruit firmer  but did not make it possible to ship riper fruit. That is a subtle biological difference that's hard to predict, but also one that cause a huge difference in value. I have followed many academic efforts at crop improvement where the transgene didn't do at all what was predicted or hoped for in the initial efficacy tests. In short, it is difficult to do crop improvement by transgenics. Conventional breeding using current genetic methods is generally faster and cheaper.

In the US, the cost of deregulating a transgenic event is currently estimated by those in the know at $3 to 5 million; it also takes many years of the inventors time to do the regulatory support for deregulation. No academic scientist has the resources to deregulate a crop, nor can they spend so many years not publishing or doing research. That reality has made transgenics unattractive in academic vegetable crops. There were some nice successes in the 1990s though. For industry, vegetable seed sales are not high enough to justify such a development cost. Monsanto offers transgenic sweet corn, but they did not transform sweet corn because of the cost, they instead did the difficult work of breeding excellent sweet corn from a transgenic field corn.

In Europe and some Asian countries, the deregulation process is far more difficult than the one in the US.

In developing a transgenic fruit or vegetable, one needs to use technologies that are patented by others. While that is not a big barrier for biological discovery, getting license agreements to commercialize a new variety has proven to be an insurmountable barrier to many.

Those are some of the reasons that I have seen influence the decisions and strategies of breeders and prospective breeders of horticultural crops.

The use of modern technologies is limited to laboratory work since distort and get  Transgenic plants stayed in greenhouses only and most of these experiments failed because the problem is not the production of Transgenic plants, but most often the problem in the environmental factor, so I think that the efforts on the laboratory work only is  mis and must work on the development of the plant in the field and can make it to coexist with the surrounding environment, and laboratory work previously and continue scientific work is limited to the laboratory

I am not sure that I completely follow this line of thinking. Globally, India was the fourth largest grower globally of transgenic crops in 2013. It is true that this was mainly Bt cotton but there was 11 million ha cultivated which is no small amount (http://www.isaaa.org/). However, it is true that other developments such as the commercial use of Bt Brinjal ( which has been under development in India for a number of years) have been impeded because of issues related to public perception. This variety of brinjal has undergone many safety tests (including environmental safety tests) so I think that is not the issue.

There are a great many hindrances, biological, political and economic.

One of the biological hindrances is that it is difficult to predict what a particular genetic modification will do. Everything on the market now has a very simple mode of action, and the concept for them was proved in the 1980s. The classic FlavrSavr tomato was intended to maintain firmness to allow shipping riper fruit. In practice, the gene ended up keeping over-mature fruit firmer  but did not make it possible to ship riper fruit. That is a subtle biological difference that's hard to predict, but also one that cause a huge difference in value. I have followed many academic efforts at crop improvement where the transgene didn't do at all what was predicted or hoped for in the initial efficacy tests. In short, it is difficult to do crop improvement by transgenics. Conventional breeding using current genetic methods is generally faster and cheaper.

In the US, the cost of deregulating a transgenic event is currently estimated by those in the know at $3 to 5 million; it also takes many years of the inventors time to do the regulatory support for deregulation. No academic scientist has the resources to deregulate a crop, nor can they spend so many years not publishing or doing research. That reality has made transgenics unattractive in academic vegetable crops. There were some nice successes in the 1990s though. For industry, vegetable seed sales are not high enough to justify such a development cost. Monsanto offers transgenic sweet corn, but they did not transform sweet corn because of the cost, they instead did the difficult work of breeding excellent sweet corn from a transgenic field corn.

In Europe and some Asian countries, the deregulation process is far more difficult than the one in the US.

In developing a transgenic fruit or vegetable, one needs to use technologies that are patented by others. While that is not a big barrier for biological discovery, getting license agreements to commercialize a new variety has proven to be an insurmountable barrier to many.

Those are some of the reasons that I have seen influence the decisions and strategies of breeders and prospective breeders of horticultural crops.

Beside some technical issues, farmers in  developing countries especially poor farmers regard biotech as a culturally sensitive technology. Many believe the technology is not in accordance with cultural and social norms, so there is need for changing attitudes and beliefs before introducing biotech to farmers.

Thanks all for sharing your valuable views with me. I came to know about the hurdles that are on the way of vegetables improvement via biotechnology. In spite of various hurdles mentioned by Thomas Björkman sir and Jamal F Hosseini sir, there are few success stories in the link http://www.isaaa.org/ of Bt cotton and Bt brinjal as said by Peter William Edward Kearns sir (Special thanks for sharing). I am highly influenced and agreeing to the views of Thomas Björkman sir. Yes i agree that there is need for changing attitudes and beliefs before introducing biotech to farmers Jamal F Hosseini sir. But still I think there is need to explore tremendous potential of biotechnology in favour of vegetables and other crops improvement programmes. Hidden possibilities are there. I am an optimistic so i am waiting eagerly for farmers oriented research outputs from biotechnology. 

I apologise for coming back late  to this discussion but I have found it interesting. I agree with Thomas Björkman that the regulatory costs of bringing a transgenic variety of a crop to the market currently inhibits all but large enterprises to be active in the field. I also agree with Thomas that some products (such FLAVR SAVR) were not successful but others have been, mainly major crops,  such as maize, soybean, rapeseed and cotton. Furthermore, they have mainly been limited to traits such as herbicide tolerance and insect resistance though others are coming through the system. I also agree that transgenesis is one useful technique but it can only be useful within the context of traditional plant breeding. However, it is also correct that the technology exists which could lead to commercial varieties of transgenics for fruits and vegetables  which are not necessarily major trading commodities and it is here that regulatory costs are a consideration.

It is interesting to note, however, that there have been many interesting developments in molecular biology such as oligonucleotide directed mutagenesis, cisgenesis, transgensis amongst others. One useful review is Lusser et al New plant breeding techniques. State-of-the-art and prospects for commercial development. Whether or not these techniques escape the costs of transgenesis will depend  on whether or not (and if so how) they are regulated. Interestingly, I have been invited to a conference on this topic next week in Jaipur, India. The International Conference on New Plant Breeding Molecular Technologies – Technology Development and Regulation.  I am looking forward to seeing how this meeting works out in the Indian context.