Stigmatic receptivity of peach flowers submitted to heat stress

Because of climatic changes, the cultivation of temperate climate plants such as peach in subtropical climates has become a challenge. In these areas, temperatures exceeding 25°C often occur during the pre-flowering and flowering phases. The high temperature causes damages by acting during the early stages of pollen-pistil interaction processes. The objective of this work was to evaluate the stigmatic receptivity of peach flowers at 18°C and 30°C. The pollen adherence was evaluated as well as the germination and presence of pollen tubes in the transmitting tissue of the style. The genotypes responded differently to temperature. ‘Granada,’ ‘Diamante’, and ‘Sensação’ had a stigmatic receptivity that was less affected when flowers were exposed to the higher temperature. Most genotypes showed a reduction in the number of pistils with pollen tubes growing in the style, particularly when pollination was delayed.