Desempenho agronômico de diferentes categorias de sementes comparadas a “grãos” em lavouras de feijão

Abstract

Brazil stands out among the main producers of legumes, with common beans (Phaseolus vulgaris L.) being an essential component of the human diet. However, productivity is low, around 950 kg ha⁻¹, although modern cultivars have a productive potential of up to 5,000 kg ha⁻¹. Among the determining factors of this limitation, the inadequate use of seeds stands out, since less than 15% of cultivated areas use legally produced seeds. In bean crops, the use of grains for sowing, called "own grains" or "saved grains," predominates. This practice compromises the quality of the plants, hinders the expression of the genetic potential of the cultivars, and favors the spread of diseases and pests. Thus, the use of legally produced seeds is fundamental for the productive efficiency of the crop, especially in the control of seed-borne diseases, which directly impact productivity. The objective of this study was to evaluate the agronomic performance of different seed categories from the Certified and Non-Certified classes of two bean cultivars, compared to different generations of saved grains in commercial crops. To this end, eight experiments were conducted, four in the 2023/2024 growing season and four in the 2024/2025 growing season. The treatments consisted of Genetic seeds, 1st generation Certified seeds (C1), 2nd generation Certified seeds (C2), 1st generation NonCertified seeds (S1) and 2nd generation Non-Certified seeds (S2), as well as saved grains from the 1st (P1), 2nd (P2), 3rd (P3), and 4th generations (P4), totaling nine treatments for the IPRUrutau and IPR-Sabiá cultivars. The experimental design adopted was a completely randomized block design with four replications. For the IPR-Urutau cultivar, treatments derived from grains showed the worst results regarding the evaluated diseases, especially for common bacterial blight (Xanthomonas axonopodis pv. phaseoli) and anthracnose (Colletotrichum lindemuthianum), with grains P2 and P4 standing out, registering the highest average severity and the highest incidence of anthracnose in the pods. A reduction in productivity was observed in grain P1, as well as a progressive increase in the occurrence of atypical plants across generations, with greater emphasis on grain P4. In the IPR-Sabiá cultivar, disease severity varied according to sowing time and treatments, with grains P1 and P3 showing the highest severity values for common bacterial blight and anthracnose. Grain P3 showed the highest incidence of anthracnose in the pods, while the lowest productivity was observed in grain P4, reinforcing the negative effect of continuous grain use on crop performance. Based on the results obtained for both cultivars, it is concluded that the severity of common bacterial blight and anthracnose was, in general, higher in the grain-derived treatments, especially in generations P2 and P4, while the genetic seed consistently showed the lowest values of Area Under the Disease Progress Curve, evidencing greater plant health. The incidence of anthracnose in the pods occurred sporadically and was restricted to certain sowing times, and angular leaf spot (Pseudocercospora griseola) remained at low levels, not constituting a limiting factor for yield. Productivity varied depending on the crop season, sowing time, and treatment, being higher and more stable in treatments with legally produced seeds