Indução de florescimento e produção de sementes botânicas em alho

Abstract

Garlic is an asexually propagated vegetable, because due to the domestication process, the evolution of the species and selection of genotypes with productive potential, it lost the ability to produce seeds. Thus, the objective of this work was to evaluate the effect of applying flowering inducers at different phenological stages of garlic on flowering induction and production of botanical seeds. The experiment was implemented in the experimental area of the horticulture sector of the Federal University of Lavras (UFLA), municipality of Lavras, MG, in April 2020. It was carried out in a randomized block design (DBC), with four replications. The test consisted of a double factorial (7x3), with seven doses of flowering inducers - GA3 and PBZ (3.5 mg L-1 of GA3; 9 mg L-1 of GA3; 18 mg L-1 of GA3; 480 mg L-1 of PBZ; 3600 mg L-1 of PBZ; 7200 mg L-1 of PBZ; control without flowering inducer) and three application times (before the differentiation of the floral scape, when the plant has four leaves; at the beginning of floral scape emission; and at the beginning of umbel formation). Plant height at flowering, number of leaves at flowering, length of floral scape, number of topsets per umbel, total flowers per umbel, flower/topset ratio, days to percentage of plants that produced scape, percentage of plants that produced umbels, total umbels with seeds, total seeds per experimental unit, percentage of plants with seeds. Also record the pollen grain viability and stigma receptivity. Data were prepared by analysis of variance using the F test (p<0.05). When necessary, they were performed as Box-cox and Rank transformations. In the presence of significance, the means were grouped by the Scott-Knott criterion for application times and for the different flowering inducers, at 5% significance. There was a negative influence of PBZ on variables related to flowering, reducing the percentage of plants with scape (PPE), percentage of plants with umbels (PPU) and the flower/topset ratio (RFT). The doses of 18 mg L-1 of GA3 and 7,200 mg L-1 of PBZ applied during umbel formation increased the stigma receptivity (SR). The application of GA3 at the beginning of floral scape emission increased the percentage of plants with umbels (PPU). The PBZ dose of 7,200 mg L-1, applied before scape differentiation increased the production of botanical seeds. The RAL 159 genotype has a natural capacity to produce botanical seeds in small quantities, without the need for exogenous application of phytohormones. The work should be repeated with a focus on applications before differentiation and during scape emission, with higher doses of GA3 and PBZ.