The researchers studied mutant rice genotypes to find ones that can grow well in drought conditions. They looked at how these genotypes grew and measured their antioxidant enzyme activities. They found that two mutant genotypes, MR219-4 and MR219-9, were able to maintain good growth and yield even under drought stress. These genotypes had higher levels of proline and antioxidant enzymes, which help them tolerate drought better than other varieties. This information can help in breeding new rice varieties that can withstand drought conditions and produce good yields.