Estimation of Genetic Components of Cocoa Populations (Theobroma cacao L.) in Seedling Phase

Abstract

Seedling is often used as planting material and rootstock for clonal propagation in cocoa. Seedling as cocoa planting material came form superior parents or crosses of superior parents. The research aimed to estimate the genetic components of cocoa morphological characters using the North Carolina II mating design. Three female parent genotypes, namely
KW 516, Sulawesi 3, and TSH 858, were crossed with two male parent genotypes, namely ICCRI 09 and Scavina 6. Observed variables consisted of plant height, stem diameter, number of leaves, leaf area, root length, root volume, shoot fresh and dry weight, root fresh and dry weight, root:shoot ratio at 16 weeks after showing. General combining ability (GCA) value showed Sulawesi 3 as the best female parent, and Scavina 6 as the best male parent. Specific combining ability (SCA) values showed TSH 858 x Scavina 6, KW 516 x ICCRI 09, and Sulawesi 3 x ICCRI 09 as the best crosses. Sulawesi 3 x ICCRI 09 seedlings had good vigor and met the criteria for transplanting. Cocoa morphological characters were affected by dominant gene action except for root volume.

Keywords: seedling, North Carolina II, general combining ability, specific combining ability