Multivariate analysis of the genetic divergence among populations of ornamental pepper (Capsicum annuum L.)

Abstract

The genus Capsicum presents a wide genetic variability. The most common way to determine this variability has been based upon morphological descriptors. We studied the genetic divergence among populations of ornamental pepper (Capsicum annuum L.) using two different multivariate techniques: Cluster analysis and canonical discriminant variables. The analyses enabled us to determine the morphological descriptors that contributed most to the genetic divergence. The study was carried out in a greenhouse in the Northeastern Brazil, in two years: 2013 and 2014. The experimental design was the completely randomized design, considering two crossed factors: Population and years. Thirteen populations of ornamental pepper were evaluated based on sixteen plant descriptors, six flower descriptors and ten fruit descriptors; eight F 3 populations, resulting from crossing the accessions 134 (P-9) and 77.1 (P-10), and five additional control populations: P-9, P-10, P-11, P-12 and P-13. There was an agreement between the two multivariate techniques in terms of distance between populations. Fruit descriptors contributed most to the genetic divergence, separating the populations used as control (P-11, P-12 and P-13) from the others. This separation is due to the uniformity of these populations in terms of fruit size and weight.

Phenotypic Dispersion of Landrace Lima Bean Varieties Using Multidimensional Scaling

“…Thus, multidimensional scaling for mixed data, with acceptable Stress level, may better discriminate the genotypes desirable for selection. Some authors, although did not use multidimensional scaling, have verified the importance of using mixed data, from Gower's distance to analyze the genetic diversity among accessions (Sudré et al, 2010;Oliveira et al, 2015;Mesquita et al, 2016;Upadhyaya et al, 2017).…”

Diversidade e seleção em população segregante de pimenteiras ornamentais (Capsicum annuum L.)

“…Foram realizadas irrigações diárias e fertirrigações semanais com solução nutritiva (Mesquita et al, 2016;. O tratamentos fitossanitários foram feitos, quando necessário, durante todo o ciclo, a fim de minimizar os danos causados por pragas e doenças.…”

“…A Universidade Federal da Paraíba (UFPB) conduziu, nos últimos anos, um programa de melhoramento de pimenteiras ornamentais cujo objetivo é o desenvolvimento de novas variedades, baseado principalmente na hibridização, gerando populações segregantes e permitindo aos melhoristas selecionar genótipos superiores, com características desejáveis para cultivo em vaso (Silva Neto et al, 2014;Rêgo et al, 2015a;Mesquita et al, 2016;Lima et al, 2019;Fortunato et al, 2019;Nascimento et al, 2019;Pessoa et al, 2019;Carvalho et al, 2021;Rêgo et al, 2022). Apesar dos avanços no melhoramento das pimenteiras, ainda se busca desenvolver variedades que atendam a expectativas de diferentes consumidores.…”