Evaluation of tropicalized carrot lines using partial diallel

Resumen

Carrot is one of the main vegetables grown in Brazil, and the seed market for this crop requires the continuous development of news cultivars with high agronomic potential. In this context, hybrid carrot cultivars stand out, as they have high-quality roots and excellent yield potential. The objective of this study was to evaluate the effects of general (GCA) and specific (SCA) combining ability between different summer carrot lines for production components, tolerance to leaf blight, and to identify the most promising lines. Crosses were performed in a partial diallel scheme 7x3, using seven male-sterile lines of Asian origin and three male-fertile parents of tropical origin, from the breeding program at Embrapa Vegetables. The experiment was conducted at the experimental field of Embrapa Vegetables, Brasília-DF, Brazil, during the 2020/21, 2021/22, and 2022/23 harvest. The experimental plot consisted of a seedbed with 1.2 m2, in RCBD ant three replications. The 21 hybrids were evaluated for tolerance to leaf blight (LB) at 90 days after sowing, and for total (TY), commercial (MY), and uncommercial (UY) root mass, and the number of marketable roots (NMR) and unmarketable roots (NUR) at 100 days after sowing. Analysis of variance and estimates of the effects of GCA and SCA were performed. GCA effects predominated over SCA for most production component traits, although SCA effects were also important, especially for controlling the expression of the LB trait. There were significant differences for the interaction between crosses x harvest of evaluation and GCA and SCA components x harvests. It was possible to select the lines A5, A7 (male-sterile), and C1 (male-fertile) as the most promising parents for the composition of summer carrot hybrids.