Path Analysis for Selection of Saccharification‐Efficient Sugarcane Genotypes through Agronomic Traits

Abstract

Sugarcane (Saccharum spp.) bagasse is recognized as a promising feedstock for cellulosic ethanol production. e development of high-quality crop cultivars through plant breeding is a way to improve feedstock quality. is study aimed to directly and indirectly quantify the e ects of agronomic characteristics on the sacchari cation of sugarcane bagasse samples and to identifying the characteristics that can be used as reliable tools for the selection of genotypes for a better biofuel feedstock. e lignin content was determined in bagasse samples of 286 clones from 13 half-sib families. Twenty clones showing a more contrasting lignin content were analyzed for the cellulose and hemicellulose composition in bagasse. ey di ered statistically for cellulose and hemicellulose contents and also for the e ciency of cellulose to glucose conversion. Clones with the highest dry biomass content also had the highest ber content and were grouped among the clones exhibiting the highest lignin content. Lignin content was statistically signi cant and positively correlated with ber (r = 0.485, p < 0.05) and plant biomass (r = 0.654, p < 0.01), and hemicellulose content was statistically signi cant and positively correlated with number of internodes (r = 0.623, p < 0.01). Lignin content and plant biomass had large negative direct e ects (0.405 and 0.784, respectively) on glucose released by enzymatic hydrolysis. Variation among clones for plant productivity parameters and chemical composition of bagasse could be exploited by breeding to increase the amount of cellulosic ethanol produced. Lignin content and plant biomass were the most important components with direct and negative in uences on the conversion of cellulose to glucose.

Genetic Variabilities and Genetic Gains for Yield Components in Regional Sugarcane Breeding Programmes on Réunion Island

“…In the present study, cane yield (CY) and sucrose content (ERS) which both determine sucrose yield per unit area showed very frequently non-significant genetic correlations which were almost null in the three programmes (LM, SB and ES) and occasionally slightly negative in one programme only (VB). Such non-significant correlations between CY and ERS have also been observed by other authors (Milligan et al 1990(Milligan et al , 1996Sandhu and Saini 1997;Baffa et al 2014;Liu et al 2016). Therefore, selection pressure exerted on one trait does not affect the other one.…”

“…Mean CV g at trial level (Table 2) was about twice as high for CY (14.1%) and EI (15.5%) compared to ERS (5.7%) and FIB (6.6%). Such large differences in genetic variation between yield (CY and EI) and quality (ERS and FIB) traits have also been found in highly selected (Brown and Glaz 2001;Tena et al 2016) and unselected (Kang et al 1990;Neto et al 2013;Baffa et al 2014) sugarcane populations. This narrow genetic variation for both ERS and FIB quality traits results from the fact that high-sugar and low-fibre parents are mainly used in our and other breeding programmes that are dedicated to industries producing sugar and first-generation bioethanol.…”

Analysis of multienvironment trials (MET) in the sugarcane breeding program of Réunion Island

“…In this hypothetical scenario, resources saved by a reduction in the number of locations could be theoretically guided by considerations relative to the selection of the stations contributing the most to genotype 9 environment interactions (highest ecovalence index) and the elimination of the very few locations most correlated to one of the former. However, the economic index (EI) is the most important trait for selection (along with resistance to diseases), and its evaluation is based on measurement of both TCH and ERS, two traits that are negatively correlated as observed by other authors (Kang et al 1983;Milligan et al 1990Milligan et al , 1996Baffa et al 2014). As a result, for this key trait, genotypic response appeared either not correlated between locations or slightly correlated between a few of them.…”

Impact of protein blocking on enzymatic saccharification of bagasse from sugarcane clones

“…Conventional plant breeding uses deliberate interbreeding (crossing) of closely or distantly related individuals to produce new varieties with desirable properties. This approach is not expected to result in large differences of lignin content since the plant does not easily lose this trait from one generation to the next (Baffa et al, ). However, two sets of ten clones were observed to have higher or lower lignin content and from those, one from each set was selected for this study.…”