Evaluation of production and quality traits in interspecific hybrids of ornamental pepper

ABSTRACT The cultivation of potted peppers as ornamental plants has increased considerably throughout the planet. In Brazil, this crop is more recent and still lacks cultivars. In order to increase the available variability and obtain new cultivars, the interspecific hybridization is very useful in add a desirable attribute that occurs in one species to another species, resulting in a new cultivar of agronomic interest. The objective of this study was to characterize parents and interspecific hybrids based on 27 quantitative traits and evaluate their genetic diversity by multivariate procedures. Parents of seven pepper genotypes were crossed, and, seven hybrids were generated. The experiment was conducted in a completely randomized design. Data were subjected to analysis of variance, and means were subsequently grouped by Scott-Knott’s method. Tocher’s method was utilized based on Mahalanobis distance, and the relative importance was evaluated by Singh’s method. The effects of treatment were significant by F test at 1 and 5% probability for all studied traits, except for anther length and titratable acidity. According to Scott-Knott’s test, the genotypes were grouped into two to eight classes. By Tocher’s method, the genotypes were separated into four groups. The first three canonical variables explained 92.02% of the total variance. By Singh method, fruit yield per plant was the trait that most contributed to the divergence explaining 21% of the total variance. The studied parents and hybrids diverged for the evaluated traits; however, there was difficulty in obtaining good interspecific hybrids with traits of importance, wherein combinations HS1×L7, L2×L6, and HS1×L2 met these requirements.

摘要 作为观赏植物的盆栽辣椒栽培规模在全球范围内显著增长。在巴西，该作物的栽培起步较晚，且目前仍缺乏适宜的栽培品种。为丰富现有种质资源多样性并培育新品种，种间杂交可将某一物种的优良性状导入另一物种，从而获得具备农艺价值的全新栽培品种。本研究旨在基于27个数量性状对亲本及种间杂交后代进行表型鉴定，并通过多元统计方法评估其遗传多样性。本试验以7份辣椒基因型作为亲本进行杂交，共获得7个杂交后代组合。试验采用完全随机设计。对数据进行方差分析后，通过斯科特-诺特法（Scott-Knott）对均值进行聚类分组；基于马氏距离（Mahalanobis distance）采用托切尔聚类法（Tocher's method），并通过辛格法（Singh's method）评估各性状的相对重要性。经F检验，除花药长度和可滴定酸度外，其余所有供试性状的处理效应均在1%和5%显著水平上达到显著。根据斯科特-诺特法（Scott-Knott）聚类结果，供试基因型被划分为2至8个类群。采用托切尔聚类法可将供试基因型划分为4个类群。前3个典型变量累计解释了总变异的92.02%。通过辛格法分析可知，单株果实产量是对遗传分化贡献最大的性状，其贡献度达总变异的21%。供试亲本及杂交后代在供试性状上存在遗传分化，但培育兼具优良农艺性状的种间杂交后代存在一定难度，其中HS1×L7、L2×L6及HS1×L2这3个组合符合选育要求。