Hi, I think there is a lot literature to read about these topics!

Cheers, Nadine

@yes, there are some reports. I have gone through few. You can check it from the literature about the plant/crop of your interest.

Regards

Hi Govind, enhancing the level of nutrients in the edible parts of food crops is the task of all farmers, plant breeders and technologist since start of agriculture. Most recent examples in my field - increased proteins content in cereals, potato, beans; oil content in oilseed rape, sunflower; sugars in fruits; vitamins in all vegetables; improved balance of aminoacids in cereals, legumes, etc.

Year , Techologist can enhance the level of the nutrients in thev edible part by enhancing the enzyme activity which is responsible for the synthesis of that component by that plant cells.

Yes, both breeders and biotechnologists can enhance the level of nutrients of our foods. Here are the examples for both:

1. Conventional breeding, carrot beta-carotene as an example:

High carotene germplasms  released by the USDA breeder in the University of Wisconsin-Madison have been the important contributor to improved pro-vitamin levels of USA carrots over the past 40 years. It estimated that the levels have increased >40% since 1970s, The most prominent example is the 'BATA III' carrot cultivar.

2. Biotechnologies, GM rice as an example:

I agree with Keith, the 'Golden Rice' which transformed with several carotene-synthesis genes to pump up beta carotene production in rice is the best example. I attached a paper describing the use of GM method to increase the trace element nutritions in plants for human beings. 

Best,

 thanks every one for your contribution and clarifications.