ABSTRACT
Winter sprouting potential and red rot resistance are two key parameters for successful sugarcane breeding in the subtropics. However, the cultivated sugarcane hybrids had a narrow genetic base; hence, the present study was planned to evaluate the Erianthus procerus genome introgressed Saccharum hybrids for their ratooning potential under subtropical climates and red rot tolerance under tropical and subtropical climates. A set of 15 Erianthus procerus derived hybrids confirmed through the 5S rDNA marker, along with five check varieties, were evaluated for agro-morphological, quality, and physiological traits for two years (2018-2019 and 2019-2020) and winter sprouting potential for three years (2018-2019, 2019-2020, and 2020-2021). The experimental material was also tested against the most prevalent isolates of the red rot pathogen in tropical (Cf671 and Cf671 + Cf9401) and subtropical regions (Cf08 and Cf09). The E. procerus hybrid GU 12-19 had the highest winter sprouting potential, with a winter sprouting index (WSI) of 10.6, followed by GU 12-22 with a WSI of 8.5. The other top-performing hybrids were as follows: GU 12-21 and GU 12-29 with a WSI of 7.2 and 6.9, respectively. A set of nine E. procerus-derived hybrids, i.e., GU04 (28) EO-2, GU12-19, GU12-21, GU12-22, GU12-23, GU12-26, GU12-27, GU12-30, and GU12-31, were resistant to the most prevalent isolates of red rot in both tropical and subtropical conditions. The association analysis revealed significant correlations between the various traits, particularly the fibre content, with a maximum number of associations, which indicates its multifaceted impact on sugarcane characteristics. Principal component analysis (PCA) summarised the data, explaining 57.6% of the total variation for the measured traits and genotypes, providing valuable insights into the performance and characteristics of the Erianthus procerus derived hybrids under subtropical climates. The anthocyanin content of Erianthus procerus hybrids was better than the check varieties, ranging from 0.123 to 0.179 (2018-2019) and 0.111 to 0.172 (2019-2020); anthocyanin plays a vital role in mitigating cold injury, acting as an antioxidant in cool weather conditions, particularly in sugarcane. Seven hybrids recorded a more than 22% fibre threshold, indicating their industrial potential. These hybrids could serve as potential donors for cold tolerance and a high ratooning ability, along with red rot resistance, under subtropical climates.
ABSTRACT
BACKGROUND: Energy canes are viable feedstocks for biomass industries due to their high biomass production potential, lower susceptibility to insects and diseases, better ability to adapt to extreme conditions and clean bioenergy. Interspecific hybrids (ISH) and intergeneric hybrids (IGH) have great potential to meet the growing demand of biomass, biomass-derived energy and feedstock. RESULTS: In this study, two types of energy canes, Type I and Type II, derived from S. spontaneum and E. arundinaceous background were evaluated for high biomass, fiber and bioenergy potential under subtropical climate along with the check varieties Co 0238 and CoS 767. Out of 18 energy canes studied, six energy canes, viz., SBIEC11008 (204.15 t/ha), SBIEC11005 (192.93 t/ha), SBIEC13008 (201.26 t/ha), SBIEC13009 (196.58 t/ha), SBIEC13002 (170.15 t/ha), and SBIEC13007 (173.76 t/ha), consistently outperformed the check varieties under Type-I, whereas in type-II, SBIEC11004 (225.78 t/ha), SBIEC11006 (184.89 t/ha), and SBIEC14006 (184.73 t/ha) energy canes produced significantly higher biomass than commercial checks, indicating their superior potential for cogeneration. Estimated energy output from the energy canes (700-1300 GJ/ha/year) exceeded the range of co-varieties (400-500 GJ/ha/year) and energy utilization efficiency in plants and ratoon crops for energy canes viz., SBIEC11008 (3%, 1.97%), SBIEC14006 (1.93%, 2.4%), SBIEC11005 (1.7%, 1.9%), and SBIEC11001 (1.01%, 1.03%), was higher than best checks Co 0238 (0.77, 0.9%). Additionally, energy canes SBIEC 13001 (22.35%), SBIEC 11008 (22.50%), SBIEC 14006 (28.54%), SBIEC 11004 (30.17%) and SBIEC 11001 (27.03%) had higher fiber contents than the co-varieties (12.45%). CONCLUSION: The study gives insight about the potential energy canes for higher biomass and energy value. These energy cane presents a vital option to meet the future demand of bioenergy, fiber and fodder for biomass due to their versatile capacity to grow easily under marginal lands without competing with cultivated land worldwide.
Subject(s)
Saccharum , BiomassABSTRACT
Marker-assisted selection (MAS) has been widely used in the last few decades in plant breeding programs for the mapping and introgression of genes for economically important traits, which has enabled the development of a number of superior cultivars in different crops. In sugarcane, which is the most important source for sugar and bioethanol, marker development work was initiated long ago; however, marker-assisted breeding in sugarcane has been lagging, mainly due to its large complex genome, high levels of polyploidy and heterozygosity, varied number of chromosomes, and use of low/medium-density markers. Genomic selection (GS) is a proven technology in animal breeding and has recently been incorporated in plant breeding programs. GS is a potential tool for the rapid selection of superior genotypes and accelerating breeding cycle. However, its full potential could be realized by an integrated approach combining high-throughput phenotyping, genotyping, machine learning, and speed breeding with genomic selection. For better understanding of GS integration, we comprehensively discuss the concept of genetic gain through the breeder's equation, GS methodology, prediction models, current status of GS in sugarcane, challenges of prediction accuracy, challenges of GS in sugarcane, integrated GS, high-throughput phenotyping (HTP), high-throughput genotyping (HTG), machine learning, and speed breeding followed by its prospective applications in sugarcane improvement.
ABSTRACT
Sugarcane is a C4 and agro-industry-based crop with a high potential for biomass production. It serves as raw material for the production of sugar, ethanol, and electricity. Modern sugarcane varieties are derived from the interspecific and intergeneric hybridization between Saccharum officinarum, Saccharum spontaneum, and other wild relatives. Sugarcane breeding programmes are broadly categorized into germplasm collection and characterization, pre-breeding and genetic base-broadening, and varietal development programmes. The varietal identification through the classic breeding programme requires a minimum of 12-14 years. The precise phenotyping in sugarcane is extremely tedious due to the high propensity of lodging and suckering owing to the influence of environmental factors and crop management practices. This kind of phenotyping requires data from both plant crop and ratoon experiments conducted over locations and seasons. In this review, we explored the feasibility of genomic selection schemes for various breeding programmes in sugarcane. The genetic diversity analysis using genome-wide markers helps in the formation of core set germplasm representing the total genomic diversity present in the Saccharum gene bank. The genome-wide association studies and genomic prediction in the Saccharum gene bank are helpful to identify the complete genomic resources for cane yield, commercial cane sugar, tolerances to biotic and abiotic stresses, and other agronomic traits. The implementation of genomic selection in pre-breeding, genetic base-broadening programmes assist in precise introgression of specific genes and recurrent selection schemes enhance the higher frequency of favorable alleles in the population with a considerable reduction in breeding cycles and population size. The integration of environmental covariates and genomic prediction in multi-environment trials assists in the prediction of varietal performance for different agro-climatic zones. This review also directed its focus on enhancing the genetic gain over time, cost, and resource allocation at various stages of breeding programmes.
ABSTRACT
BACKGROUND: Glyoxalase pathway is a reactive carbonyl species (RCS) scavenging mechanism involved in the detoxification of methylglyoxal (MG), which is a reactive α-ketoaldehyde. In plants under abiotic stress, the cellular toxicity is reduced through glyoxalase pathway genes, i.e. Glyoxalase I (Gly I), Glyoxalase II (Gly II) and Glyoxalase III (Gly III). Salinity and water deficit stresses produce higher amounts of endogenous MG resulting in severe tissue damage. Thus, characterizing glyoxalase pathway genes that govern the MG metabolism should provide new insights on abiotic stress tolerance in Erianthus arundinaceus, a wild relative of sugarcane and commercial sugarcane hybrid (Co 86032). RESULTS: In this study, three glyoxalase genes (Glyoxalase I, II and III) from E. arundinaceus (a wild relative of sugarcane) and commercial sugarcane hybrid (Co 86032) were characterized. Comparative gene expression profiles (qRT-PCR) of Glyoxalase I, II and III under salinity and water deficit stress conditions revealed differential transcript expression with higher levels of Glyoxalase III in both the stress conditions. Significantly, E. arundinaceus had a higher expression level of glyoxalase genes compared to commercial sugarcane hybrid. On the other hand, gas exchange parameters like stomatal conductance and transpiration rate were declined to very low levels under both salt and drought induced stresses in commercial sugarcane hybrid when compared to E. arundinaceus. E. arundinaceus maintained better net photosynthetic rate compared to commercial sugarcane hybrid. The phylogenetic analysis of glyoxalase proteins showed its close evolutionary relationship with Sorghum bicolor and Zea mays. Glyoxalase I and II were predicted to possess 9 and 7 isoforms respectively whereas, Glyoxalase III couldn't be identified as it comes under uncharacterized protein identified in recent past. Chromosomal mapping is also carried out for glyoxalase pathway genes and its isoforms. Docking studies revealed the binding affinities of glyoxalase proteins in both E. arundinaceus and commercial sugarcane hybrid with their substrate molecules. CONCLUSIONS: This study emphasizes the role of Glyoxalase pathway genes in stress defensive mechanism which route to benefit in progressive plant adaptations and serves as potential candidates for development of salt and drought tolerant crops.
