Genotype x Environment Interactions in Sugarcane under Irrigation for Agronomic Traits at Advanced Screening Stage in Ferké, Northern Ivory Coast

Abstract

Background: The selection procedure of commercial sugarcane varieties introduced in Ivory Coast involves two different stages. Four varieties pre-selected at the first stage regarding a previous trial were due to be tested at the advanced stage.
 Aims: The study aimed to determine the best performing sugarcane genotypes at the advanced selection stage under sprinkler irrigation, in comparison with to two check varieties (R579, SP70-1006).
 Methodology: The same field experiment was carried out on two different locations in Ferké 2 sugar estate of Northern Ivory Coast. The experimental design used was a randomized complete block (RCB) with six cane genotypes in four replications. Every plot consisted of five dual rows of ten meters with 0.5 and 1.90 m of inter-row spacing, i.e. 95 m² per plot and about 3000 m² for each experiment. Both experiments were conducted over two seasons (plant cane and first ratoon) as early-season crops from early November, 2017 to mid-December, 2019. Over each micro-plot, data based on different agro-morphological traits were collected at harvest from three central dual rows. 
 Results: The study showed that most relevant traits in genotype clustering were related to juice quality (recoverable sucrose, sucrose content, purity), yields and yield components (Millable stalk number/ha, stalk height, stalk diameter, internode number). Based on sugar yields, two genotypes (N47, ECU01) superior to both check varieties were found promising with, respectively, 13.7 and 13.5 t sugar/ha. Their cane yield performances gave 124 and 123 t/ha, respectively, compared to 126.8 t/ha for the best performing check.
 Conclusions: Not only sugar yield, but also flowering rate, stem borer infestation rate, stalk diameter, average stalk height and the number of tillers per hectare were found as the most relevant agronomic traits in the genetic variation of sugarcane genotypes tested. It came out also that GxE interactions were highly significant for five different traits, namely, cane and sugar yields, stalk borer infestation rate, fiber content and the average stalk height.