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

Abstract

Sugarcane variety development programmes are costly and lengthy. It appears important to periodically assess their ability to select competitive genotypes for yield components and provide genetic gains. This article reports a 10-year retrospective analysis of successive variety trials conducted in four regional breeding programmes on Réunion Island in the most advanced regional selection stage. The four variety programmes were dedicated to the humid coastal zone (LM), the per-humid coastal zone (SB), the irrigated dry coastal zone (ES) and the dry high lands (VB) of the local industry. Using mixed linear models, the objective of the study was to (1) assess genetic variabilities available for yield components in this advanced selection stage; and (2) estimate trends of genetic gains achieved over the last decade across the four programmes. Yield components were: cane yield (CY), estimable recoverable sugar (ERS), fibre content (FIB) and economic index (EI). Broad-sense heritabilities were high (0.70-0.91) for all traits in each programme. Mean genetic coefficients of variation were about twice as high for CY (14.1%) and EI (15.5%) compared to ERS (5.7%) and FIB (6.6%). A higher probability of identifying superior varieties was found for CY and EI in two of the four programmes characterized either by thermal and hydric stresses (VB) or by an edaphic stress (SB). Simple linear regression of variety performances versus years of selection revealed trends in genetic gains for EI ranging between 0.53 and 1.81% increase per year that were highly significant (P \ 0.001) in the two programmes (LM and VB).

Genetic Variability and Heritability among Sugarcane Genotypes in Plant Crop for Some Agronomic Traits under Tropical Dry Climate of Ferké, Ivory Coast

“…All yield and juice quality traits were negatively correlated with stem borer infestations except for fiber content (Table 2) in line of findings reported by different authors [39][40][41]. This shows that in stem borer infestations tended to increase fiber content of cane stalks.…”

Evaluation of Sugarcane Genotypes Under Irrigation Based on Genetic Variations and Heritability for Agronomic Traits at Early Selection Stage in Ferké, Ivory Coast

“…Sugarcane flowering impacted negatively on stalk internode number as exhibited by a correlation coefficient of -0.32***, while it enhanced cane and sugar yields with values of 0.28*** and 0.27*** respectively. The cane fiber content was correlated positively to internode number (0.42***) and stem borer infestations rate (0.30***), but negatively to cane yield (0.21***) as reported by different investigators [5,[40][41]. More importantly, it was not negatively correlated to the recoverable sucrose in contrast of findings obtained in the same agro-ecological context [42].…”

“…From the literature, findings on heritability, genetic gain, PCV and GCV for the same traits look sometimes controversial depending on locations, crop cycle (plant cane or ratoon), soil types, water regime (rainfed or irrigated), etc. [6,22,40,59]. But still, this is all about the scope of experimentation in agronomy, findings being mostly site-specific.…”

Near-infrared spectroscopy outperforms genomics for predicting sugarcane feedstock quality traits

“…The estimated broad-sense heritability values indicate that the selection of clones for these trait based on phenotypic values would be effective since environment variance has shown little impact [48]. Ramos et al (2017) [49] found similar values of h 2 for FIB and PC.…”