Genótipos de soja e ferrugem asiática (Phakpsora pachyrhizi): correlações, reação, adaptabilidade e estabilidade

• Autor(a) principal: Tancredi, Fábio Daniel
• 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/123456789/1091
• topic: Glycine max; Ferugem asiática; Produção; Glycine max; Asian rust; Yield; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

This work was carried out during the agricultural years 2004/05 and 2005/06 in the Experimental Field of Agronomy - Fundão DFT/UFV, the soil having been prepared in the usual way. Each genotype was represented by a row of 5 x 0,70 m, with plant density varying from 10 to 14 plants/m, sown on 03/12/2004 and 06/01/2006. Before sowing, the seeds were inoculated with B. japonicum. The fungicide used to control the rust was Tebuconazole. The plants were thinned out at the V2 development stage. As a border, two lateral rows were sown without fungicide application. A control of weeds and other harmful plants was carried out. Characteristics evaluated included growth, flowering, maturation, final height of the plant, height of the first pod insertion, number of nodes on the main stem/plant, number of pods/plant, number of grains/plant, medial number of grains/pod, weight of the plant, weight of pods/plant, weight of the main stem/plant, weight of grains/plant, medial weight of grains/plant, weight of one hundred grains, production of grains/ha and index of crop/plant. The statistical analyses were accomplished using the application computational in genetics and statistics, GENES Program. In the agricultural year 2004/05 aimed to estimate correlations between the agronomic characteristics of soybean genotypes naturally infected by P. pachyrhizi, which causes Asian rust, in two situations, with and without the fungicide application; evaluate soybean genotypes in relation to their tolerance to the Asian rust, according to the evolving severity of the disease and its influence on the growth, development and production of grains. The data was analyzed using descriptive statistics. The experiment consisted of two trials: one without fungicide application and other with. In total 92 soybean genotypes divided into four groups by maturity were appraised. Some of them originate from the germplasm bank of the Soybean Genetic Improvement Program of DFT/UFV, some were sent in from seed producing companies. Manuring of the sowing area was carried out using 04-14-08 at a rate of 600 kg ha-1. From the study of the correlation between the agronomic characteristics and the severity of the rust at different evaluation times, it is concluded that, in cases of late occurrence of the disease and the advanced development stage of the genotypes, the best results were verified in the late maturing group. From the correlations between the agronomic characteristics and the different times of evaluation of the rust, it was observed that the most damaged characteristics were height of the first pod insertion, number of nodes on the main stem, number of pods, weight of the plant, weight of the pods, weight of grains, weight of the main stem and production of grains. From the study of the correlation between the agronomic characteristics in the trials with and without fungicide application, it was concluded that, between the trials, a difference was verified in the extent of the relationship among the appraised characteristics. It was observed variation of values and significance of the correlations, so much among the trials as for the groups of maturity studied. The trial without fungicide application promoted anticipation in the cycle of semi-precocious, medium and semi-late maturing group genotypes, and increased the height of the first pod insertion in the semi-late maturing group genotypes. For the characteristic production of grains, the trial without fungicide application resulted in medium reductions of 55,77 to 71 %. The genotypes that presented larger tolerance to the Asian rust were Java, PI 281891, PI 341241 and UFVTN 104 of the semi-late maturing group, and PI 200487, PI 200670 and PI 341262 of the late maturing group. In the agricultural year 2005/06 aimed to quantify the interaction of genotype x environment on the agronomic characteristics and the performance of soybean cultivars with the occurrence of P. pachyrhizi; estimate the adaptability and stability of the production of 12 soybean cultivars in two trials, with and without fungicide application, to control the Asian rust fungus, combined with five formulations of fertilized sowing. For installation and statistical analysis, the triple factorial scheme 12 cultivars x with and without fungicide application x five formulations of fertilizer with nitrogen (N), phosphorus (P2O5), potassium (K2O) and silicon (SiO3) was used, with three repetitions, in random block-type delineation. The chemical analysis of the soil was made to a depth of 0 to 0,20 m. The data was submitted to variance analysis. A joint analysis was carried out considering the combination of the trials with and without fungicide application with the formulations of fertilization in the 10 environments comprising the interaction of genotype x environment study. The averages were compared, using the tests F and, or, Tukey at 1 and, or, 5 %. The analyses of adaptability and stability were carried out according to the methods proposed by Eberhart and Russell (1966), Lin and Binns (1988) modified by Carneiro (1998), Annicchiarico (1992) and the Centróide Method (Rocha et al., 2005).The cultivars with a tendency to a greater weight of plant and pods presented a potential for a larger production of grains: Emgopa 313 in environments without fungicide application and Uirapuru in environments with application. In the average environment, the one with fungicide application and 20 kg ha-1 N, 90 kg ha-1 P2O5, 70 kg ha-1 K2O and 69 kg ha-1 SiO3 was the most favourable to increase the yield of grains. In the average cultivars, the most productive was UFVS 2005. The most productive cultivars between the four groups of maturity were: M-SOY 6101 (semi-precocious), BRSMG 68 [Vencedora] (medium), P98C81 (semi-late) and UFVS 2005 (late). Eberhart and Russell (1966) methodology proved efficient for identification of the cultivars, however, differed from others to indicate them. The best cultivars for wide adaptability, according to the methodologies of Lin and Binns (1988) modified by Carneiro (1998), Annicchiarico (1992) and the Centróide Method (Rocha et al., 2005), were Emgopa 313 and BRSMG 68 [Vencedora], there was a distinction of UFVS 2005 and BRSMT Uirapuru in favourable environments and of M-SOY 6101 and CS 201 Splendor in unfavourable environments.