Genetic Variability and Heritability among Sugarcane Genotypes at Early Stage of the Advanced Selection for some Agronomic Traits in Ferké, Northern Ivory Coast

Abstract

Selection in sugarcane from true seed was recently implemented in Ivory Coast with the aim to increase the genetic variability of crop material used and, therefore, improve significantly sugar yields with a positive impact on the competitiveness of the Ivorian sugar industry. The objective of study was to determine the best performing cane genotypes among 29 clones tested under sprinkler irrigation, in comparison with a check variety (R579). It was carried out on R3-002 commercial sugarcane plantation of Ferké 2 sugar estate, in northern Ivory Coast. The experimental design used was a randomized complete block with 30 cane genotypes in three replications. Each plot comprised two dual rows of five meters with 0.5 and 1.90 m of inter-row spacing, i.e. 19 m2 per plot and about 600 m2 for the whole experiment. Based on sugar yields, four promising genotypes namely RCI12/15, RCI12/19, RCI13/121 and RCI13/136 were equivalent to the check variety which performed 15.6 t/ha. They are due to undergo the advanced selection stage during the 2020-21 cropping season for three more years for determining the first new sugarcane varieties of RCI origin to be tested commercially in Ferké sugar estates. Their yield performances ranged from 12.8 to 13.8 t sugar/ha, i.e. from 134.0 to 144.8 t cane/ha compared to 161.3 t/ha for the control variety. Although a relatively high level of stem-borer infestation rate recorded, with 15.6% on average (almost three times the tolerable threshold value of 5%), reasonable values of sucrose percent obtained with the promising genotypes, ranged from 12.7 to 13.9% over both crop cycles, compared with 13.6% for the check. Higher heritability values ranging from 61 to 80.5% were observed in traits like sugar yield, sucrose content (62.6%), recoverable sucrose (60.6%), fiber content (72%), stem-borer infestation rate (80.5%), number of internodes/stalk (67.7%), and flowering rate (79.6%). In contrast, lower and moderate values of heritability were observed for Pol juice (59.8%), juice purity (50.5%), cane yield (53%), millable stalk number/ha (29.5%), single stalk weight (36.7%), single stalk height (45%), and single stalk diameter (38.7%).