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Red rot caused by the fungus Colletotrichum falcatum is the main disease limiting sugarcane productivity in several countries including the major producer India. The genetic basis for red rot resistance is unclear. We studied a panel of 305 sugarcane clones from the Australian breeding program for disease response phenotype and genotype using an Affymetrix® Axiom® array, to better understand the genetic basis of red rot resistance. SNP markers highly significantly associated with red rot response (≤ 10-8) were identified. Markers with largest effect were located in a single 14.6 Mb genomic region of sorghum (the closest diploid relative of sugarcane with a sequenced genome) suggesting the presence of a major-effect QTL. By genomic selection, the estimated selection accuracy was ~0.42 for red rot resistance. This was increased to ~0.5 with the addition of 29 highly significant SNPs as fixed effects. Analysis of genes nearby the markers linked to the QTL revealed many biotic stress responsive genes within this QTL, with the most significant SNP co-locating with a cluster of four chitinase A genes. The SNP markers identified here could be used to predict red rot resistance with high accuracy at any stage in the sugarcane breeding program.

This investigation aimed to optimize the time, pH, pressure, and temperature of sugarcane juice pasteurization and to develop a “ready to serve” bottled sugarcane juice with a high preservation efficiency. Fresh sugarcane juice was extracted from sugarcane genotype Co 89003, and beverage samples were collected using three different treatments: sulphitation of juice with the addition of potassium metabisulphite (KMS-25, 50, 100, and 150 ppm), acidification of juice (addition of citric acid, to reduce the pH of the juice to 4.8, 4.5, and 4.25), and steam treatment of the canes (5 min, 10, and 15 min at 7 psi). In all treatments, the juice was pasteurized in glass bottles @ 65 °C for 25 min and stored at low temperature (5 °C) in pre-sterilized glass bottles. Juice properties such as the ˚Brix, total sugar, pH, and total phenolic content decreased with storage, whereas the microbial count, titrable acidity, and reducing sugar content significantly increased during storage. The addition of KMS, citric acid, and the steam treatment reduced the browning of juice and maintained the color of juice during storage, by inhibiting the polyphenol oxidase enzyme activity, from 0.571 unit/mL to 0.1 unit/mL. Among the selected treatments, sugarcane juice with KMS (100 and 150 ppm) and steam treatment of the canes for 5 and 10 min at 7 psi showed the minimum changes in physico-chemical properties, sensory qualities, and restricted microbial growth. Thesulphitation treatment with pasteurization proved best for increasing the shelf life of sugarcane juice upto 90 days with refrigeration. Similarly, the steam-subjected cane juice (10 and 15 min at 7 psi) could be effectively preserved for upto 30 days with refrigeration, without any preservative.