Unlocking the mystery of heterosis opens the era of intelligent rice breeding.

Heterosis refers to the phenomenon where the first filial offspring (F1) from genetically diverse parents displays advantages in growth rate, yield and adaptability compared to its parents. The exploitation of heterosis in rice breeding has greatly increased the productivity, making a significant contribution to food security in the last half of century. Conventional hybrid rice breeding highly relies on the breeder's experience on random crossing and comprehensive field selection. This process is time-consuming and labor-intensive. In recent years, rice hybrid breeding has encountered challenges stemming from limited germplasm resource, low breeding efficiency and high uncertainty, which constrain the progress in yield increase, coupled with difficulties in balancing grain yield, quality and resistance. Understanding the genetic basis of rice heterosis could lead to significant advances in breeding concepts and methods. This will fully unleash the advantages of heterosis. In this review, we focus on the research progress of the genetic dissection of crop heterosis, and introduce briefly on some key advancements in modern intelligence breeding of rice hybrid.