Optimizing breeding strategy of Melaleuca cajuputi subsp. cajuputi for a multiple-trait selection: considering the economic weight of traits for oil yield productivity

Abstract

Melaleuca cajuputi breeding in Indonesia is entering the advanced generation cycle and improvements have been achieved for oil concentration and 1.8 cineole-content. In commercial plantations, the total oil yield is an important factor to ensure the sustainability and continuity of oil production. This variable is calculated based on oil concentration, survival rate, and leaf biomass. However, to date, biomass productivity is maintained through silviculture practices rather than genetics. Therefore, genetic improvement for other traits related to leaf biomass is necessary. This study aimed to optimize the breeding strategy of M. cajuputi for a multiple-trait selection using the economic weight of traits related to oil yield. The economic weight was derived by combining selection results in the past generation breeding population and the assessment in genetic gain trials. The study revealed that leaf biomass should be prioritized as selection criteria for oil concentration in the advanced generation breeding based on the current baseline of the achieved gain. The implication of the economic weight to further generation breeding selection for improving oil yield productivity is that the major traits affecting the oil yield should be incorporated simultaneously for selection in the breeding strategy of M. cajuputi. The leaves biomass could be more weighted than other traits in constructing the index for the multiple-trait selection considering the correlation among the three traits observed.