Caracterização morfológica e avaliação agronômica de acessos de Feijão-de-metro em Manaus, Amazonas

Abstract

The yardlong bean (Vigna unguiculata subsp. sesquipedalis (L.) Verdc.) belongs to the Fabaceae family. In Amazonas, the use of local yardlong bean varieties by smallholder farmers has ensured the conservation of genetic diversity. The selection of genetic materials is essential for breeding programs, as it contains various pieces of information that can be explored through characterization and evaluation studies. However, there are still few studies on the characterization and evaluation of yardlong beans in the region. In this regard, the present study aimed to morphologically characterize and agronomically evaluate accessions of yardlong bean varieties in the drylands of the Central Amazon. The experiment was conducted at INPA’s Vegetable Research Station, using seeds from the local varieties Preto, Branco, and Marrom, obtained from INPA’s plant germplasm collection, in addition to the ‘De Metro’ cultivar as a control. The design was a randomized block design in a 4 x 2 factorial scheme, consisting of three local varieties and one commercial cultivar, evaluated over two growing seasons (February–May and August–November). A total of 20 descriptors related to plants, leaves, flowers, fruits, and yield were used. The varieties analyzed showed high stability in their qualitative traits across seasons, such as: a pronounced tendency toward curling; a climbing growth habit; very light pigmentation of the stem and branches; a lanceolate shape of the apical leaflet blade in the Branco variety, while in the Preto, Marrom, and commercial ‘De Metro’ varieties it was sub-lanceolate; green coloration of the apical leaflet blade in the Preto variety, while in the other genotypes evaluated it was dark green; very slight pigmentation on the petiole; violet coloration of the flowers; very slight pigmentation of the pod peduncle; no pigmentation on the pod; light green coloration of the pod in the Preto variety, dark green in the Branco variety and in the ‘De Metro’ cultivar, and green in the Marro variety. Thus, qualitative differentiation was established based on the characteristics of leaf blade shape, coloration of the apical leaflet, and coloration of the pods. Phenotypic plasticity was observed among the varieties, with the rainy season favoring vegetative growth and the accumulation of photosynthates, thereby increasing yield potential. The Branco and Marrom varieties stood out for having the highest average yields, maintaining high yield levels in both growing seasons; the ‘De Metro’ cultivar stood out for its shorter growth cycle; and although the Preto variety recorded the lowest production rates, it should not be ruled out, as it may possess characteristics of interest for breeding that have not yet been evaluated, requiring further in-depth studies.