Evaluating Family by Environment Interactions and Combining Ability in Seedling Populations of the Louisiana Sugarcane ( <i>Saccharum</i> spp. Hybrids) Breeding Program

ABSTRACT With the recent and rapid expansion of the Louisiana Sugarcane industry further north and west, sugarcane breeders are forced to re‐evaluate the Louisiana Sugarcane Variety Development Program (LSVDP) to accommodate emerging industry needs such as fitness to heavier soils and potentially colder environments. Family selection is the preferred method of selection in true seedling populations of sugarcane. In this study, we sought to explore the potential presence of family‐by‐environment interaction (FEI) effects at three sites to represent the recent expansion and how these FEI might influence selection in seedling populations. With mixed‐linear modelling, we were able to (1) evaluate genetic variance and potential genetic gains, (2) identify numerous significant sources of family‐by‐environment interaction effects, (3) understand the genetic control of these traits by estimating specific‐combining ability (SCA) of families and general‐combining ability (GCA) of female and male parents and (4) describe what these mean for seedling selection in the LSVDP. Notably, family‐by‐location and female‐by‐location interaction effects were significant for various traits of interest, extending FEI into different individual parent breeding values at the three chosen sites. Sugarcane breeders in Louisiana may consider accommodating the FEI effects as strategies are developed to adjust seedling selection intensity and target new environments in the industry. Capturing the additive and non‐additive genetic effects via GCA and SCA estimations, respectively, can further aid adjustments and strategies for predictive breeding, especially in the early clonal stages of the program.