Repeatability of morpho-agronomic characters of Theobroma grandiflorum fruits

Abstract

The objective of this study was to estimate coefficients of repeatability, to determine the minimum number of fruits necessary for genotype selection and to estimate phenotypic correlation coefficients between morpho-agronomic characters of Theobroma grandiflorum fruits. It was evaluated twenty - two genotypes of an agroforestry system implanted in the municipality of Cantá - RR. Ten fruits per genotype were collected and evaluated for longitudinal length, transverse diameter, total weight, peel thickness, peel weight, pulp weight, placental weight and wet seed weight. Four statistical methods were used to estimate the repeatability coefficients: variance analysis, main components based on the correlation matrix and the covariance matrix, and structural analysis based on the correlation matrix. The number of measurements needed to predict the real value of the genotypes and the Pearson correlation coefficients among the characters were also estimated. The repeatability coefficients ranged from low to moderate, with 10 fruits per plant generally required, with 85% of confidence, in order to make an effective selection for most of the characters studied. There are possibilities of indirect gains for fruits with greater amount of pulp through the selection of larger and / or heavier fruits.

Repeatability coefficient estimates and optimum number of harvests in graft/rootstock combinations for 'tahiti' acid lime

“…In the results of this study, the estimated repeatability was classified as moderate for NFP and FYP and low for TFD and LFD. Similar findings have been reported for other fruit crops, such as banana (Lessa et al, 2014), sweet orange (Negreiros et al, 2008), cashew (Maia et al, 2016), guava (Quintal, Viana, Campos, Vivas, & Amaral Junior, 2017), mangaba (Fonseca et al, 2018), grapes (Leão, Nunes, & Souza, 2018), and cupuassu (Alcoforado, Pedrozo, Mayer, & Lima-Primo, 2019).…”

Canopy replacement used in the evaluation of cupuassu tree genotypes in the state of Pará

“…The size of the fruit itself, especially the diameter was indicative of heavier fruit and, consequently, with higher pulp yield. Similar behavior was observed in Alcoforado et al (2019) for the same variables. However, heavier fruits will not necessarily have a high seed yield.…”

“…The fruits evaluated in the present study showed average values higher than those obtained by Alcoforado et al (2019) for the average of the characteristics FrL (223.6 mm), FrD (106 mm), PT (6.7 mm), PeM (943.6 g), SM (156.9 g), PP (384, 4 g) and FM (943.6 g). A similar situation was repeated when they were compared with the data obtained by Costa et al (1997) and Maia et al (2011).…”