Humanity confronts a major transition in the global environment. With the continued rise in atmospheric
greenhouse gases, and wide-spread land transformation, the climate of the planet could warm to levels that have not existed for tens of millions of years. Crop yields are particularly vulnerable to high
temperatures and plant reproduction is amongst the most sensitive of the physiological components at
temperatures above 30
◦
C. In this review, we examine the effect of high temperatures on plant reproduction in general, and then focus on heat-induced failure of male and female reproduction in crop and model
plant species in order to evaluate the patterns and mechanisms controlling heat sterility responses. The
main objective is to provide breeders and molecular engineers with an understanding of the bottlenecks
for successful reproductive development at high temperatures. Although numerous stages of male and
female reproduction are impacted by elevated temperatures, the collective body of research supports the
view that the uninucleate stage of male reproductive development is highly sensitive to levels of heat
stress currently experienced by many crop species. Thus, high priority should be given to identification
of mechanisms leading to high temperature sensitivity of this stage of development.