Productivity, physicochemical quality and early flowering resistance of experimental onion hybrids

ABSTRACT In order to produce bulbs or seeds, onion plants depend on genotype X environment interaction. Thus, breeders shall select the genotypes based on the climatic conditions of each producing region. This study aimed to evaluate 17 experimental onion hybrids and two commercial genotypes (‘Bella Dura’ and ‘Buccaneer’), based on agronomic, physicochemical attributes of the bulbs and resistance to early flowering under subtropical conditions. Joint analysis of variance and phenotypic divergence estimated through principal component analysis (PCA) and Ward’s hierarchical clustering were performed. We observed that the time of transplantation affected the agronomic traits more than the physicochemical traits, not affecting the percentage of early flowering of the genotypes. The first transplant season provided higher bulb productivity, whereas the second season reduced the cycle and productivity. Hybrids H1, H17 and ‘Buccaneer’ showed flowering rate lower than 3%. Among the experimental hybrids, H2 showed higher productivity when comparing with commercial cultivars, and H1, H12 and H14 were equivalent to them. However, H12 showed the highest early flowering rate (43%). Thus, considering the experimental genotypes evaluated under subtropical conditions, H1, H2, and H14, showed potential for commercial use or as potential parents in advancing the breeding program, as they stood out for presenting good yield, bulb quality and low percentage of early flowering.

摘要 为获得鳞茎或种子，洋葱植株依赖于基因型-环境互作（genotype X environment interaction）。因此，育种者需根据各产区的气候条件筛选基因型。本研究旨在基于亚热带条件下洋葱鳞茎的农艺性状、理化特性及抗早花性，评估17个洋葱试验杂交种与2个商业基因型（‘Bella Dura’与‘Buccaneer’）。本研究开展了联合方差分析，并通过主成分分析（Principal Component Analysis, PCA）与沃德分层聚类（Ward’s hierarchical clustering）进行表型分化分析。研究发现，移栽时间对农艺性状的影响大于对理化特性的影响，且不会影响各基因型的早花率。首个移栽季的鳞茎产量更高，而第二个移栽季则缩短了生育期并降低了产量。杂交种H1、H17与‘Buccaneer’的早花率低于3%。在试验杂交种中，H2的产量高于商业品种，H1、H12与H14的产量则与商业品种相当。但H12的早花率最高，达43%。综上，在亚热带条件下评估的试验基因型中，H1、H2与H14表现出商业化应用潜力，或可作为育种项目改良的潜在亲本；这三个材料因兼具优良产量、鳞茎品质与较低的早花率而脱颖而出。