Predictive power of YREMs and BLUPs for selecting superior genotypes in perennial crops: A black pepper case study

Black pepper (Piper nigrum L.), a highly sought-after spice crop with medicinal properties, requires careful evaluation and selection due to its perennial nature and associated resource requirements. Being a perennial, yield trials across years are feasible and practical in this crop rather than that across locations. However, parameters to assess the yield trial data and/or derive criteria to select superior cultivars with stable performance are lacking in black pepper. In this study, we examined the genotype-by-year interaction (GYI) pattern and its impact on black pepper yield, as well as the selection parameters for identifying stable and high-yielding cultivars. Average Yield Relative Environment Maximum (YREM) and Best Linear Unbiased Predictor (BLUP) emerged as the most effective measures for evaluating cultivar performance, as they accounted for relative yield and stability. Among the evaluated cultivars, OPKM displayed better stability estimates. However, considering high mean yield along with all the stability estimates, the HP 2173 ranked first. Notably, even with single-location multi-year trial data, the single-year YREM and BLUP values showed significant predictive power for future performance which is most preferred in perennial crops. Additionally, the use of multi-year average performance (YREM and BLUP) as quantitative criteria for selecting or rejecting genotypes in future breeding programs proved to be effective.