Vânia Aparecida Silva

Resposta fisiológica de clone de café Conilon sensível à deficiência hídrica enxertado em porta-enxerto tolerante

The objective of this work was to determine alterations in physiology and those due to drought tolerance on Conilon coffee (Coffea canephora) contrasting clones regarding the sensitivity to hydric stress. The reciprocal grafting between clones 109A, drought sensitive, and 120, drought tolerant, - 120/109A, 120/120, 109A/120, 109A/109A - along with their ungrafted control plants (109A and 120) were evaluated. Plants were cultivated in 12‑L vases in greenhouse. Six months after grafting, half of the plants was subjected to water deficit, by suspending irrigation until leaves reached the hydric potential of ‑3,0 MPa. When clone 120 was used as rootstock, plants presented deeper roots, although with lower root-biomass, higher ability to postpone leaf dehydration and higher instantaneous water‑use efficiency (WUE). Under severe drought, starch and sucrose contents decreased similarly, regardless of the treatment, whereas leaf concentrations of glucose, fructose, total amino acids and proline were higher in non‑grafted 109A, 109A/109A, and 120/109A plants. These plants showed the lowest WUE values. Solute accumulation was not primarily related to drought tolerance. The use of drought tolerant rootstocks improves to drought tolerance in coffee.

Resistência mediada por aleloquímicos de genótipos de tomateiro à mosca-branca e ao ácaro-rajado

The objective of this work was to assess the degree of resistance to the whitefly (Bemisia argentifolii) and to the two-spotted spider mite (Tetranychus urticae) of tomato hybrids resulting from crosses between high-zingiberene (ZGB) lines and high-acylsugar (AS) lines, as compared to their parental lines and to commercial vouchers. High-AS lines, high-ZGB lines, double heterozygous (ZGB+AS) hybrids, hybrids heterozygous for ZGB and hybrids heterozygous for AS were tested. The wild accessions PI 127826 and LA-716 were used as high-ZGB and high-AS vouchers, respectively, while the genotypes Debora Max and TOM-684 were used as vouchers for low ZGB and AS. The genotypes were submitted to resistance tests to the whitefly and repellency to the spider mite. Double heterozygous (ZGB+AS) hybrids were more resistant to whiteflies than the commercial vouchers, but less resistant than the high-ZGB or the high-AS lines. Double heterozygous (ZGB+AS) hybrids were more repellent to the spider mite than the commercial vouchers, and their repellency to mites was similar to that of high-ZGB or high-AS lines. There was no synergistic effect between ZGB and AS, for both resistance to the whitefly and repellency to the two-spotted spider mite, in the double heterozygous (ZGB+AS) genotypes.

Concentração do ciclo de produção de pinhão-manso por meio de podas de formação ou de produção

The objective of this work was to evaluate the possibility of reduction in the production cycle of physic nut (Jatropha curcas) by the use of different formation or production pruning. One experiment for each kind of pruning was carried out in the semiarid region of Minas Gerais state, Brazil, with five treatments each. Treatments were related to primary branch pruning heights, and to pruning or elimination of secondary branches. With the formation pruning, it was possible to reduce the harvest period from 120 to 48 days, but always with significant losses in plant yield in the first cycle. Production pruning can concentrate harvest in 90 days and, in some cases, improve plant yield.

Sistemas intercalares com abacaxizeiro como alternativa de renda durante a formação de cafezais irrigados

O objetivo deste trabalho foi determinar o sistema de plantio de abacaxizeiro intercalado com cafeeiro que proporciona o maior retorno economico, sem comprometer o desenvolvimento vegetativo e a produtividade de cafezal irrigado. Utilizou-se o delineamento em blocos ao acaso, com quatro repeticoes e dez plantas uteis por parcela. Os sistemas irrigados de cultivo consistiram em: duas e tres fileiras simples de abacaxizeiro, nas entrelinhas do cafeeiro, ou quatro linhas em fileiras duplas. O desenvolvimento vegetativo do cafeeiro foi avaliado aos 6, 12 e 18 meses apos o plantio, e a produtividade aos 28 meses. O cultivo de duas fileiras simples favoreceu o desenvolvimento do cafeeiro, e os demais sistemas nao tiveram efeito sobre esse parâmetro. A produtividade do cafeeiro foi maior nos sistemas de cultivo com duas e tres fileiras de abacaxi. Os tres sistemas de cultivo apresentaram retornos economicos positivos. O sistema intercalar com tres fileiras simples proporciona o melhor retorno, sem comprometer o desenvolvimento vegetativo e a produtividade do cafeeiro.