Assessment of Harvest Age of some Sugarcane Genotypes by using es by using Principal Component Analysis

Abstract

Two field trials were conducted in Upper Egypt conditions at Kom Ombo Agricultural Research Station, (latitude of 24o 28′N and longitude  of 320. 57′ E), Aswan Governorate, Egypt during 2019/2020 and 2020/ 2021 seasons (plant cane and first ratoon) to determine  the optimum harvest age of the major sugarcane promising genotypes (G. 2003-47, G. 2004-27, G. 2005-47, G. 84-47 and G.T.54-9). The  AMMI (Additive main effects and multiplicative interaction) analysis and PCA (principal components biplot) analysis, were utilized to  examine and understand the relationship between genotype and environment (G x E). The experimental design was a split plot with  three replications. Results showed that harvest ages significantly varied among all studied traits in plant cane as well as first ratoon  season. Harvest age of 13 months recorded the highest mean values of stalk length, stalk diameter, stalk weight, brix %, cane and sugar  yields, except richness %, sucrose % and sugar recovery % in first ratoon crop and across crops where it recorded the highest values at  age of 12-months. By contrast, reducing sugars % and purity % in plant cane, first ratoon and over crops where it recorded the greatest  values at age of 10-months and 12-months, respectively. The G. 84-47 genotype surpassed the other genotypes and produced the highest  values of brix %. G. 2003-47 genotype surpassed the other genotypes and produced the highest values of sucrose %, purity %  and sugar recovery %. Results of the Principal Component Analysis (PCA) showed that the first two components had an Eigen value > 1  and explained about 84.37 % of the total variation among all analyzed variables. The first component (PC1) explained 50.8, 54.2, 45.7, and  57 % of the total variation among the tested sugarcane genotypes assessed by different harvesting ages (10, 11, 12 and 13 months)  measured for the plant cane and first ratoon seasons and the second component (PC2) explained 38.5, 35.8, 42.6, and 34.6% of the total  variation measured by the same variables, respectively. The PC1 had a strong negative correlation with brix % measured at all harvesting  ages. The PC1 had a moderate negative correlation with sucrose and sugar recovery and a moderate positive correlation with stalk  diameter, reducing sugars and sugar yield calculated based 10, 11 and 12 months. Results display positive correlation and highly  significant between cane yield, stalk weight, then cane yield and stalk length followed by cane yield and stalk diameter. Based on the AMMI analysis: the five sugarcane genotypes under investigation could be divided into three groups, early maturity (G 2003-47 and G  84-47) , mid maturity ( G2004-47) and late maturity (G 2005-47 and GT 54-9).