The major product formed in the following reaction is

Concept:

• Cycloaddition reactions are light or heat assisted combination of two alkene systems. 
• The product has two extra strong \(\sigma\) bonds. This is the driving force of reaction
• These reactions follow concerted mechanism
• [2+2] cycloaddition is one such class of cycloaddition reaction
• Allenes contain consecutive double bonds joined by sp hybridized C. Allenes also shows cycloaddition reactions.

Explanation:

The given allene system will show [2+2] cycloaddition with another alkene system on thermal assistance.

The less hindered double bond of allene will participate more in the reaction and will give major product.

Since, the reaction follows the concerted mechanism, stereochemistry of substituent is not affected. Therefore, the major product will have same orientation as in reactant, that is, the product will be trans for the given reaction.

Conclusion:

Therefore, the major product of given reaction is: