Multivariate analysis of sugar yield components in sugarcane

Two field experiments were conducted at Mallawy Research Station Menia Governorate during the two successive seasons of 2009/2010 and 2010/2011 to evaluate some statistical methods that used for estimating the relative contribution of sugar yield components in sugarcane crop. The present work included nine treatments which were the combination between three treatments of growth promoters (Agrispon Stimulate and control) and three genotypes of sugarcane namely: G.T. 54-9, G. 84-47 and Phil- 8013. Five statistical procedures were used to study the relationship between sugar yield and its components using the data over the two seasons. The used methods of analysis were simple correlation coefficient path analysis full model regression, stepwise multiple linear regression and factor analysis. Highly significant and positive correlation coefficients were detected between sugar yield and each of number of internodes/stalk, number of millable stalks/m2 total soluble solids % and sucrose %. The results of path analysis revealed that the number of millable stalks/m2 was the most important trait with the highest direct and indirect effects on sugar yield followed by sucrose % and stalk weight. The same three traits were also responsible for the most sugar yield variability using full model regression and stepwise multiple linear regression with goodness of fit of the two models. Factor analysis grouped the studied eight traits as sugar yield components into three main factors accounting for 85.3 % of the total variability in the dependence structure. Factor I was responsible for 34.89 of the total variation and included stalk weight, stalk diameter and number of millable stalks/m2. Factor II contained total soluble solids % and sucrose % and contributed to 28.17 % of the total variation. Stalk length, number of internodes/stalk and reducing sugar % were the components of the last factor and explained 22.25 % of the total variation. Based on the previous results it could be concluded that the high sugar yield of sugarcane crop would be abtained by selecting breeding materials that have heavy weight of stalk large number of millable stalks/m2 and high percent of sucrose.