The scientists studied how different types of rice plants can be crossed to create hybrids with better traits. They used genetic markers to measure the differences between the parent plants and predict how well the hybrids would perform. They found that the genetic distance between parent plants was related to the hybrid's performance in traits like tiller number and panicle length. In some cases, the genetic distance was also linked to grain yield. However, for other traits, the markers used were not as helpful. This suggests that using more specific markers could improve predictions of hybrid performance.