Garlic breeding suffers from limited genetic variability and poor adaptability to tropical lowland environments due to high temperatures and humidity. This study aimed to compare the genetic variability and selection efficiency of the M2 garlic mutants in two contrasting areas (highland and lowland) in Central Java, Indonesia. The experiment has an augmented research design. The results showed the analysis of genetic parameters confirms that the highland environment optimizes the expression of the genetic potential of the M2 garlic mutants. Conversely, with the environmental stress, the garlic mutants still exhibited sufficient variability for selection based on bulb weight. Obtaining a total of 29 mutants came from the highlands, and 13 were from the lowlands. The PCA biplot successfully validated the G × E interaction by explaining 55.41% of the total variance. Mutants H28, H29, H15, and H23 express potential as putative highland-adapted mutants. Meanwhile, mutant L9 displays adaptability to lowland areas. As a plant propagated vegetatively, garlic allows for the genetic fixation of induced superior traits in subsequent generations. Although there is a single-season constraint, screening these early generations using biplot analysis provides an efficient framework for initial selection.
Garlic (A. sativum L.), gamma irradiation, M2 mutants, genetic variability, heritability and genetic gain, lowland adaptation, augmented design, yield traits
The M2-generation garlic (A. sativum L.) mutants exhibited reduced heritability for vegetative traits due to high temperature and humidity stress in lowland areas. Nevertheless, the 13 mutants maintained the high bulb weight despite environmental stress, demonstrating that direct selection in the target environment was highly effective for isolating mutants resistant to high temperature and humidity.