Seleção precoce e fenotipagem do sistema radicular de linhagens de milho em função de nitrogênio e fósforo

• Autor(a) principal: Vaz de Melo, Aurélio
• 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/123456789/1095
• topic: Zea mays; Melhoramento; Genética; Eficiência de uso; Estresse abiótico; Zea mays; Breeding; Genetics; Use efficiency; Abiotic stress; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

This work aimed: 1 - select and evaluate the genetic divergence of corn line in the stadium of four leaves completely developed as for the root system and efficiency of use of nitrogen and phosphrus; 2- evaluate the behaviour of corn line in function of the doses of nitrogen and phosphrus; 3 - select and phenotiping corn line as for the architecture of the seminal roots in relation to primary root of the plant and; 4 - to evaluate the viability of the methods of the electric capacitância of the plant, reading of the index SPAD and of notes of symptoms of deficiencies and foliar architecture in the precocious selection of corn line as for the use of nitrogen in low phosphrus readiness. To reach the objectives 1 and 2 they experiments they were accomplished in vases, with soil, vegetation home. In each experiment, one with 10 mg dm-3 and other with 60 mg dm-3 of N, they were appraised five phosphrus doses (160, 320, 480, 640 and 800 mg dm-3 of P2O5). In the objective 1, they were appraised 10 lines and in the objective 2, six lines were selected, being three efficient and three inefficient. In the objective 3 they were appraised other 20 corn lines in nutritious solution in glass boxes covered with aluminum foil in temperature and ambient humidity. In the objective 4 an experiment was accomplished vegetation home, to evaluate other 30 corn lines as for the effects of the doses of 10 and 60 mg dm-3 of combined N with the dose of 320 mg dm-3 of P2O5. Was ended that genetic divergence exists among the corn line as for the root system and the efficiency of use of nitrogen and phosphrus; the area of the root system is the characteristic that more contributed to the genetic variability; the selection of corn line for efficiency of nitrogen in high N depends on the phosphrus dose and in low N it doesn't depend on the phosphrus dose; the line 1 was selected as inefficient and no responsive; the lines 9 and 10 were selected as efficient and responsive; the dose 320 mg dm-3of P soil provided better conditions for study of the genetic divergence; the line selected in high N with base in EUN and other characteristics is different from the line selected in low N. the corn line present different answers as EUN and EUP in agreement with the doses of nitrogen and phosphrus. in low N the line L9 is efficient in the use of N and the line L10 is responsive to this nutritious one in high N; the corn lines L11 and L14 have the largest angles of the seminal roots; the lines L15 and L17 have them largest density of hair roots; the line L11 was the one that stood out with larger number of seminal roots; the line with larger area of the system root in low N are L11, L41 and L39 and; the use of the capacitância, index SPAD and notes looks are appropriate methodology for the precocious selection and phenotiping of corn line as for the root system and the use of nitrogen and phosphrus.