Biochemical descriptors: importance of the genetic divergence study in peppers

ABSTRACT The genetic diversity of pepper genotypes is usually evaluated based on morphological and molecular descriptors. However, studies using biochemical descriptors of peppers are still incipient. Thus, the objective of this study was identify biochemical descriptors of Capsicum spp. with antioxidant action, most responsive to the selection of superior genotypes, and evaluate the correlation between concentrations of the parameters using principal components analysis. The experiment was conducted in the city of Cáceres, southwest Mato Grosso, Brazil. Seventy-eight pepper accessions from the Active Germplasm Bank of UNEMAT were planted in randomized block design. The harvested fruits were immersed in liquid nitrogen for two minutes, and the following biochemical analyses were performed: titratable acidity, ascorbic acid, total phenols, flavonoids, anthocyanins, carotenoids, chlorophyll a, chlorophyll b, and antioxidant activity. Biochemical descriptors that best estimated the genetic variability of the accessions were flavonoids, total phenols, chlorophyll a, and ascorbic acid. Chlorophyll a and chlorophyll b were the compounds that showed the highest degree of correlation. Except chlorophyll a with ascorbic acid, all other vectors showed correlation ranging from moderate to strong.

摘要：辣椒基因型的遗传多样性通常通过形态学与分子描述指标进行评估，但针对辣椒生化描述指标的相关研究仍处于起步阶段。为此，本研究旨在筛选出具有抗氧化活性、最适用于优异基因型选育的辣椒属（Capsicum spp.）生化描述指标，并采用主成分分析（principal components analysis）法分析各参数浓度间的相关性。本试验于巴西马托格罗索州西南部的卡塞雷斯市开展。本研究种植了来自UNEMAT活性种质资源库（Active Germplasm Bank）的78份辣椒种质材料，采用随机区组设计（randomized block design）。将采收后的果实置于液氮中浸泡2分钟，随后开展以下生化分析：可滴定酸度（titratable acidity）、抗坏血酸（ascorbic acid）、总酚类（total phenols）、类黄酮（flavonoids）、花青素（anthocyanins）、类胡萝卜素（carotenoids）、叶绿素a（chlorophyll a）、叶绿素b（chlorophyll b）及抗氧化活性（antioxidant activity）。能够最优评估种质遗传变异的生化描述指标为类黄酮、总酚类、叶绿素a与抗坏血酸。叶绿素a与叶绿素b的相关性程度最高。除叶绿素a与抗坏血酸外，其余所有指标间的相关性均为中等至强相关。