Qualidade fisiológica e sanitária de sementes de cultivares de soja colhidas em diferentes épocas e horários

• Autor(a) principal: Toledo, Márcia Ribeiro
• Data de Publicação: 2008
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1092
• topic: Soja; Semente; Vigor; Viabilidade; Tetrazólio; Soybean; Seeds; Vigour; Viability; Tetrazolium; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

The objective of this work was to evaluate the influence of the time of the day and harvest time on seed sanitary quality of soybean cultivars. Five different times of the day (8:00 and 10:00 am, and 12:00, 2:00 and 4:00 pm) and two harvest times (R8 and R8 + 15 days) in association with fourteen cultivars (Conquista, Vencedora, Sambaiba, Garantia,, UVF 16, UFV 18, UFVTN 102, UFVS 2005, UFVS 2006, UFVS 2008, UFVS 2011, UFVS 2012, UFVS 2015 and UFVS 2018). After harvest, seeds from each treatment were separated into two lots. Data were examined using analysis of variance in a 14 x 2 x 5 factorial scheme, in a complete randomized design, with four repetitions. Results were also interpreted through cultivar clustering using the average linkage method based on the standardized Euclidean distance with results from germination, vigor, tetrazolium and sanitary tests performed with the two seed lots. In the tetrazolium test, the viable seeds (live seeds) were within classes 1 to 5, and seed vigor was within classes 1 to 3. Causes of seed viability loss were evaluated by the mean percentage of classes 1 to 8, being separated into mechanic, moisture and stinkbug damages. The first seed lot was used for germination, emergence in sand bed, accelerated aging, tetrazolium and sanitary tests. The second lot was stored for six months in ambient conditions and then undergone the same germination, emergence in sand bed and accelerated aging tests. The results obtained after field harvest showed that cultivars Sambaíba, UFVS 2005, UFVS 2012 and UFVS 2015 had the highest potential for germination and vigor in the three evaluations. After the storage period, the seeds with the best potential for germination and vigor were UFVS 2008, UFVS 2012, UFVS 2015 and UFVS 2018. The harvest stage caused more damage to germination and vigor than the times of the day. The tetrazolium test indicated that the smallest percentages of mechanic damages occurred when seeds were harvested at R8 + 15 days in the afternoon, and that the harvest delay seemed to have increased the damage by moisture. The sanitary evaluation showed that the most frequent fungi were Fusarium sp. and Phomopsis sp., and incidence of Phomopsis sp. and total fungi increased with harvest delay. Among the evaluated cultivars, UFV6 showed the highest incidence of fungi at all times of the day and harvest times. The clustering of cultivars allowed the identification of groups for selection with higher physiological and sanitary quality of seeds.