Physiological and Yield Characteristics of 18 Sugarcane Genotypes Grown on a Sand Soil

Abstract

ABSTRACTGrowth, yield, and yield components of sugarcane (a complex hybrid of Saccharum spp.) are important traits for growers to evaluate cultivars and for scientists to select best genotypes in the breeding and cultivar development programs. Collection of these yield data across genotypes would be labor intensive and time consuming in the early selection stages of the breeding programs with a large number of genotypes. A field experiment was conducted on a sand soil to investigate physiological and yield characteristics of 18 sugarcane genotypes and to determine relationships of leaf relative chlorophyll (SPAD reading), leaf net photosynthetic rate (Pn), and canopy normalized difference vegetation index (NDVI) with yield traits, including stalk population, length, diameter, weight, cane yield (tonnes of cane per hectare [TCH]), commercial recoverable sucrose, and sucrose yield (tonnes of sucrose per hectare [TSH]) across genotypes. The NDVI values were calculated based on canopy reflectance in the red (680 nm) and near‐infrared (800 nm) spectra measured using a multispectral radiometer. Among yield traits, stalk population and TCH were most highly correlated with NDVI and/or Pn. Although stalks and TCH were highly and linearly (P < 0.0001) related to NDVI measured in April to August, the best stage of measuring NDVI for yield assessment in Florida across genotypes was during tillering and early grand growth (before canopy closure). Therefore, measurements of NDVI before canopy closure could be useful for predicting plant growth and yield potential across genotypes in cultivar selection programs and used as an agronomic management tool in sugarcane production.