I dusted off a copy of the classic article by Johnston and Mellor in 1961 on The Role of Agriculture and Development (in the American Economic Review). Reading it now I realize how remarkable it was - much of the later insight on agriculture and development were presaged in its pages. The emphasis on broad-based technological change; the possibility of financing industrial investment through agricultural savings; and the compatibility of high labor use with a modernized, high-yielding agriculture (departing from the Western model of highly productive, but also highly mechanized farms).
Just to let you know: there is an ongoing debate in the literature between agriculture optimism (or agriculture fundamentalism) and agriculture pessimism (or agriculture skepticism). The former advocates an agriculture-led strategy of growth; the latter holds that in some (or perhaps many) cases agricultural development can essentially be bypassed in the process of economic development. Johnston and Mellor themselves were not so fundamentalist in their advocacy of agriculture (though later Mellor was to turn hardcore).