It has been some time that I worked on crops and have never formally done GMOs. But a quick and dirty survey of the literature does enforce my memory of having read that some GMOs increase yields and farm income. There has been a controversy I had followed from afar, but my impression seems to have been correct:
"A 2010 article supported by CropLife International summarised the results of 49 peer reviewed studies.[391][392] On average, farmers in developed countries increased yields by 6% and 29% in developing countries."
https://en.wikipedia.org/wiki/Genetically_modified_food_controversies#Yield
"Onfarm field trials carried out with Bacillus thuringiensis (Bt) cotton in different states of India show that the technology substantially reduces pest damage and increases yields. The yield gains are much higher than what has been reported for other countries where genetically modified crops were used mostly to replace and enhance chemical pest control. In many developing countries, small-scale farmers especially suffer big pest-related yield losses because of technical and economic constraints. Pest-resistant genetically modified crops can contribute to increased yields and agricultural growth in those situations, as the case of Bt cotton in India demonstrates."
Yield Effects of Genetically Modified Crops in Developing Countries | Science
"The largest gains in farm income in 2014 have arisen in the maize sector, largely from yield gains.
The $5.3 billion additional income generated by GM insect resistant (GM IR) maize in 2014 has
been equivalent to adding 6.1% to the value of the crop in the GM crop growing countries, or
adding the equivalent of 3.2% to the $163 billion value of the global maize crop in 2014.
Cumulatively since 1996, GM IR technology has added $41.4 billion to the income of global maize
farmers. "
http://www.pgeconomics.co.uk/pdf/2016globalimpactstudymay2016.pdf
"The GM IR traits, used in maize and cotton, have accounted for 95.3% of the additional maize
production and 99.3% of the additional cotton production. Positive yield impacts from the use of
this technology have occurred in all user countries (except for GM IR cotton in Australia where
the levels of Heliothis sp (boll and bud worm pests) pest control previously obtained with
intensive insecticide use were very good). The main benefit and reason for adoption of this
technology in Australia has arisen from significant cost savings and the associated environmental
gains from reduced insecticide use, when compared to average yields derived from crops using
conventional technology (such as application of insecticides and seed treatments). The average
yield impact across the total area planted to these traits over the 19 years since 1996 has been
+11.7% for maize and +17% for cotton. "
http://www.pgeconomics.co.uk/pdf/2016globalimpactstudymay2016.pdf