Derivate OJIP Variables in Sugarcane to Predict Cane Weight, Sucrose Content, and Sugar Yield

Abstract

The amount of carbohydrates in sugarcane directly results from photosynthesis. This means that we can predict the weight of the cane, sucrose content, and sugar yield by examining the photosynthesis process. One way to measure the amount of photosynthesis is by using chlorophyll fluorescence or the OJIP test. This study aimed to determine the dominant OJIP variable that could predict cane weight, sucrose content, sugar yield, and measurement time. The study was conducted at the Asembagus Experimental Station in Situbondo Regency, East Java, Indonesia, from December 2016 to October 2017 using two-bud stem cuttings from 18 sugarcane clones and arranged them in a Randomized Block Design with three replications. Each clone in one replication was planted in five rows, each row being five meters long, and the center-to-center distance was 130 cm. OJIP variables were measured during the stalk elongation phase and the maturity phase. The results showed that sugarcane clones influenced OJIP variables other than Fv/Fm, cane weight, sucrose content, and sugar yield. The most accurate time for measuring OJIP variables was during the maturity phase. The dominant OJIP variables that could predict cane weight and sugar yield were TRo/RC, DIo/CS, ABS/RC, and PI (79.4% and 76.0%). The dominant predictors of yield were RC/CSo, RC/CSm, DIo/CS, PI, ABS/RC, and ETo/RC (92.9%). This study found that measuring OJIP variables during the maturity phase is ideal for predicting cane weight, sucrose content, and sugar yield. The OJIP test can quickly identify high-yielding sugarcane varieties.