Molecular Characterization and Evaluation of Special Sugarcane Varieties Suitable for Co-Generation of Power

Sugarcane is a major agro-industrial crop in India. The fibre content in sugarcane is gaining importance as fuel for co-generation of electricity. Hence, the present study was proposed to genetically characterize and identify suitable clones for co-generation with high yielding, optimum sucrose per cent, erect, non-lodging and good ratooning ability characters. Genetic analysis of 10 sugarcane hybrids was carried out using STMS primers. Out of 110 markers amplified, 77.27 % were polymorphic with an average of 8.5 polymorphic products per STMS primer. Similarity coefficient value of 0.79 and 0.48 was detected with closely and distantly related hybrids respectively. The average genetic similarity among the hybrids was ~78.6%. These results indicated the existence of moderate level of genetic diversity among these high biomass hybrids. Evaluation trial in replicated randomized block design including five early and five mid late clones was conducted at Regional Agricultural Research Station (RARS), Anakapalle during 2007 to 2010. Early clones viz., CoA 03081 (123.0 t/ha and 14.93 t/ha), CoA 02081 (122.0 t/ha and 14.78 t/ha) and CoA 07321 (118.7 t/ha and 14.10 t/ha) were significantly superior for cane and CCS yields than the best standard Co 7508 (104.0 t/ha and 13.34 t/ha). Midlate clones viz., CoA 07322 (137.0 t/ha and 17.12 t/ha) and CoA 02082 (132.0 t/ha and 17.00 t/ha) were significantly superior over the standard CoV 92102 (125.0 t/ha and 16.95 t/ha) for cane and CCS yields. The fibre content of the early and midlate clones ranged from 18.67 (CoA 02081) to 22.50 (CoA 03081) and 20.17 (CoA 07322) to 23.00 (CoA 03082), respectively. These elite clones recorded resistant reaction to red rot disease. The results revealed the potential of these clones suitable for co-generation of power with high yielding, high fibre content, optimum sucrose per cent and good ratooning ability.

Rapid detection of red rot disease pathogens (Pythium chondricola/P. porphyrae) in Pyropia yezoensis (Rhodophyta) using PCR-RFLP method

Red rot disease is one of the most well-known algal diseases infecting red algae Pyropia species. This disease seriously decreases the quality and quantity of Pyropia aquaculture products in Korea, Japan, and China. Recently we first found that Pythium chondricola (Oomycetes) infecting blades of Pyropia yezoensis. Therefore two Pythium species (P. chondricola/P. porphyrae) have been reported as red rot disease pathogens. In this study, we developed a species-specific molecular marker for discriminating the two red rot disease pathogens. Using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method based on the mitochondrial cytochrome c oxidase subunit 2 (cox2) and nuclear ribosomal RNA large subunit (LSU) regions, these two Pythium species were successfully classified without a sequencing step. This new method showed high specificity and efficiency for detecting red rot disease pathogens at the species level for both of the cultured samples and field samples. Therefore the molecular markers developed in this study are effective for long-term monitoring on the infection and distribution pattern of each Pythium species in Pyropia aquaculture farms. Moreover, the molecular monitoring can provide useful information for predicting infection and preventing mass mortality of Pyropia species by red rot disease.

Phylogenetic Analysis and Genetic Diversity of Colletotrichum falcatum Isolates Causing Sugarcane Red Rot Disease in Bangladesh

Colletotrichum falcatum Went causes red rot disease in sugarcane farming in the tropical and sub-tropical regions. This disease causes significant economic loss to the sugarcane production industry. Successful disease management strategies depend on understanding the evolutionary relationship between pathogens, genetic diversity, and population structure, particularly at the intra-specific level. Forty-one isolates of C. falcatum were collected from different sugarcane farms across Bangladesh for molecular identification, phylogeny and genetic diversity study. The four genes namely, ITS-rDNA, β-tubulin, Actin and GAPDH sequences were conducted. All the 41 C. falcatum isolates showed a 99–100% similarity index to the conserved gene sequences in the GenBank database. The phylogram of the four genes revealed that C. falcatum isolates of Bangladesh clustered in the same clade and no distinct geographical structuring were evident within the clade. The four gene sequences revealed that C. falcatum isolates from Bangladesh differed from other countries´ isolates because of nucleotides substitution at different loci. The genetic structure of C. falcatum isolates were determined using ISSR marker generated 404 polymorphic loci from 10 selected markers. The percentage of polymorphic loci was 99.01. The genetic variability at species level was slightly higher than at population level. Total mean gene diversity at the species level was 0.1732 whereas at population level it was 0.1521. The cluster analysis divided 41 isolates into four main genetic groups and the principal component analysis was consistent with cluster analysis. To the best of our knowledge, this is the first finding on characterizing C. falcatum isolates infesting sugarcane in Bangladesh. The results of this present study provide important baseline information vis a vis C. falcatum phylogeny analysis and genetic diversity study.

Resistance to Red Rot Disease (Colletotrichum falcatum) Varies among Different Germplasm Sources of Sugarcane

Resistance of sugarcane varieties to red rot disease is essential for their successful commercial cultivation in Pakistan. Evaluation of sugarcane germplasm for red rot resistance is a basic component of the varietal development system in Punjab. The studies on varietal screening against red rot disease of exotic sugarcane germplasm were conducted at the research farm of the Sugarcane Research Institute, Faisalabad from 2008–2009 to 2010–2011. The screening test was carried out at different varietal development stages including sugarcane nursery-2, nursery-3, semi-final varietal trial, final varietal trial and National Uniform Yield Trial by using plug method of inoculation. In three years, 724 sugarcane genotypes were examined in screening test against red rot disease, which were developed from germplasm (fuzz), imported from different sugarcane breeding organizations of the world. Fuzz is a true seed of sugarcane used to develop new sugarcane variety(ies) through repeated selection in any varietal development program. The results of three years experimentation revealed that 425 genotypes were resistant, 141 moderately resistant, 48 moderately susceptible and 110 susceptible to red rot disease. It was also concluded that sugarcane germplasm belongs to the USA, proved to be superior for resistance to red rot disease with 91% genotypes followed by Brazil and Australia with 86 and 68% genotypes, respectively, which were classified in resistant and moderately resistant category. © 2021 Friends Science Publishers

Current and Prospective Strategies on Detecting and Managing Colletotrichumfalcatum Causing Red Rot of Sugarcane

Sugarcane is an important industrial crop because it is the major source of white sugar. It is also one of the crops for the alcohol and biofuel industries. Disease-causing organisms can significantly decrease the productivity of sugarcane plants and sugar quality. Among the disease-causing organisms, Colletotrichum falcatum Went causes the most significant economic loss (5–50%) in the sugarcane production due to red rot disease. This loss results in only 31% sugar recovery. It is reported that C. falcatum can kill sugarcane plants. Currently, there is no sustainable way of preventing red rot disease from spreading in sugarcane plantations. Many popular sugarcane varieties are no longer used in sugarcane cultivation because of their susceptibility to C. falcatum. The objectives of this manuscript were to: (i) summarize existing approaches for the early detection of red rot disease and controlling techniques of red rot disease in the field and laboratory and (ii) assess red rot disease control effectiveness so as to propose better methods for mitigating the spread C. falcatum. If our proposition is adopted or practiced, it could significantly contribute to the mitigation of C. falcatum infection in the sugarcane industry. This could enable achieving sustainable cultivation of sugarcanes to guarantee the sustainability of the sugar industry in the tropics and the subtropics.

A pathogen of New Zealand Pyropia plicata (Bangiales, Rhodophyta), Pythium porphyrae (Oomycota)

© 2017 The Korean Society of Phycology. Geographic distributions of pathogens are affected by dynamic processes involving host susceptibility, availability and abundance. An oomycete, Pythium porphyrae, is the causative agent of red rot disease, which plagues Pyropia farms in Korea and Japan almost every year and causes serious economic damage. We isolated an oomycete pathogen infecting Pyropia plicata from a natural population in Wellington, New Zealand. The pathogen was identified as Pythium porphyrae using cytochrome oxidase subunit 1 and internal transcribed spacer of the rDNA cistron molecular markers. Susceptibility test showed that this Pythium from New Zealand was able to infect several different species and genera of Bangiales including Pyropia but is not able to infect their sporophytic (conchocelis) phases. The sequences of the isolated New Zealand strain were also identical to Pythium chondricola from Korea and the type strain from the Netherlands. Genetic species delimitation analyses found no support for separating P. porphyrae from P. chondricola, nor do we find morphological characters to distinguish them. We propose that Pythium chondricola be placed in synonymy with P. porphyrae. It appears that the pathogen of Pyropia, both in aquaculture in the northern hemisphere and in natural populations in the southern hemisphere is one species.

A pathogen of New Zealand Pyropia plicata (Bangiales, Rhodophyta), Pythium porphyrae (Oomycota)

© 2017 The Korean Society of Phycology. Geographic distributions of pathogens are affected by dynamic processes involving host susceptibility, availability and abundance. An oomycete, Pythium porphyrae, is the causative agent of red rot disease, which plagues Pyropia farms in Korea and Japan almost every year and causes serious economic damage. We isolated an oomycete pathogen infecting Pyropia plicata from a natural population in Wellington, New Zealand. The pathogen was identified as Pythium porphyrae using cytochrome oxidase subunit 1 and internal transcribed spacer of the rDNA cistron molecular markers. Susceptibility test showed that this Pythium from New Zealand was able to infect several different species and genera of Bangiales including Pyropia but is not able to infect their sporophytic (conchocelis) phases. The sequences of the isolated New Zealand strain were also identical to Pythium chondricola from Korea and the type strain from the Netherlands. Genetic species delimitation analyses found no support for separating P. porphyrae from P. chondricola, nor do we find morphological characters to distinguish them. We propose that Pythium chondricola be placed in synonymy with P. porphyrae. It appears that the pathogen of Pyropia, both in aquaculture in the northern hemisphere and in natural populations in the southern hemisphere is one species.