Melhoramento genético da abobrinha italiana: estratégias para fenotipagem e seleção de híbridos experimentais

Abstract

The objective of this work was to study the agronomic performance, genetic diversity and repeatability of Italian zucchini hybrids. The experiment was conducted in 2020, in which 33 Italian zucchini hybrids were evaluated, of which 31 are new experimental hybrids and two commercial ones (Adele and Clarice). The design used was in randomized blocks with four replications and six plants per plot. In addition to the total and commercial productivity of fruits, quantitative and qualitative morphoagronomic characteristics were evaluated. From the data obtained, the agronomic evaluation of the hybrids was carried out; the study of genetic diversity and correlations between evaluated characters; and the repeatability study to determine the optimal number of harvests for reliable selection. It was observed for the agronomic performance that all hybrids presented good uniformity, good format, good length and great diameter of fruits. The quantitative variables number of total and commercial fruits and total productivity, 12 hybrids representing 36.36% of all, stood out for their excellent results and good yield, similar to those of commercial cultivars. Hybrids HT19165, HT19107, HT19109, HT19120 were the most divergent hybrids among all, including commercial cultivars. In the dendrogram they formed three groups, in which the hybrids HT19165 and HT19109 stood out forming one of these groups and were considered the most divergent hybrids. Correlations were positive for the quantitative variables between total fruit number, marketable fruit number, total yield, marketable yield and fruit length. With only 15 fruit harvests, R2≥90% is not reached, that is, with this amount of harvests, the R2 of 70% was reached, which, for the beginning of the improvement programs, was already possible to separate the good hybrids from the bad ones. Thus, it can be concluded that among the 33 hybrids evaluated, there were superior hybrids with high productive potential, divergent, with good correlations between the quantitative variables. And finally, what repeatability in the culture of Italian zucchini for high precision requires a high number of harvests for all variables performed.