What is the main conflict in The House of Bernarda Alba by Federico Garcia Lorca?

The play, along with Blood Wedding and Yerma, forms a trilogy expressing what Lorca saw as the tragic life of Spanish women. These late works Dennis Klein in Blood Wedding, Yerma, and The House of Bernardo, Alba called "the most accomplished and mature efforts of the finest Spanish playwright of the twentieth century." If Blood Wedding is a nuptial tragedy and Yerma the tragedy of barren women, The House of Bemarda Alba might be seen as the tragedy of virginity, of rural Spanish women who will never have the opportunity to choose a husband. It is also a play expressing the costs of repressing the freedom of others.