Cultivation in Green House during Hot summer weather

Hi All… its has been a wonderful experience reading all important experiences from all the members on this websites.
I am into Naturally ventilated Green House Cultivation for almost 3 years now in Pushkar- Ajmer- Rajasthan.
I am cultivating Dutch Rose, Gerbera, Capsicum & Cucumber in different different Polyhouses.
But a common problem I have observed is that during High Temperature season i.e. from April to Mid July, production greatly decreases along with quality of the products.
Can any one suggest any Crop that can be grow in Polyhouse during warm dry weather. I haven’t tried Musk Melons but I think that can a very effective crop during that period. Anyone having experience in cultivation of Musk Melons or any other crops may please guide on this issue. Your value comments are welcome. My contact details are 9829577606.