Quantifying sugarcane cultivar differences in tiller and stalk phenology: identifying traits suited to crop model-assisted breeding

Abstract

ABSTRACTThe “Canegro” sugarcane (Saccharum spp.) model uses cultivar trait coefficients to simulate crop growth. The primary objective of this study was to quantify the cultivar trait values for some tillering and stalk traits for a diverse range of cultivars. An additional objective was to determine the stability and heritability of these traits across environments and crop stages to assess their potential contribution to model-assisted breeding. A total of 12 diverse cultivars were evaluated in a rainfed and an irrigated environment across two crops (plant cane and first ratoon). The traits peak tiller population (PTP), thermal time to peak tiller population (TTPP), final population (FPOP), tiller survival percentage (TSP) and stalk elongation rate (SER) were derived from in-season measurements. The highly significant (p < 0.001) effect of cultivar was larger than the cultivar × ratoon and cultivar × site effects for all traits studied. The traits PTP, FPOP and SER showed strong cultivar rank correlations between sites, crops, and crops within sites, suggesting that they can be quantified per cultivar by single-site and single-crop experiments. These traits had heritability estimates of 0.70 (PTP), 0.97 (FPOP), and 0.72 (SER). Hence, these traits were identified as good candidates for model-assisted breeding. Some cultivars showed consistent rankings for certain traits and were identified as ideal indicator cultivars for future characterization studies. The cultivar trait values determined here will be used to calibrate the crop model. The range of values for these traits will also contribute to model-wise exploration of genotype × environment interactions and model-assisted breeding efforts.