Avaliação do desenvolvimento inicial de acessos de camu-camu (myrciariadubia(kunth) mcvaugh) em diferentes condições edafoclimáticas no estado de Roraima

Abstract

Camu-camu (Myrciariadubia (Kunth) McVaugh) is an indigenous fruit of the floodplain and riparian forests of the Amazon region. In Brazil, Roraima State has appropriate soils and climate conditions for its cultivation in savanna (lavrado) and rainforest areas, with wide altered/degradatedareas to be converted into productive fields. Cultivation outside floodplains can improve fruit availability, since flowering occurs almost all year round and more pronounced fruiting in periods coinciding with the end of the dry and early rain seasons. The objective of this study was to evaluate the vegetative development of 6 camu-camu subsamples selected from INPA in a savanna area, in Boa Vista, Roraima, and in a transition savanna/forest area, in Mucajaí, Roraima. The experiments were conducted in two areas of EMBRAPA, the Água Boa Experimental Station, with coordinates at 2°39'59'' N and 60°50'21'' W, with climate type Aw, according to Köppen climate classification and at the Serra da Prata Experimental Station, in Mucajaí, Roraima whose geographical location is found at 60°58'40"W; 2°23'49"N, with climate type Am. For growth analysis, parameters such as basal trunk diameter (mm), plant height (cm), number of basal shoots and number of terminal shoots were evaluated. Measurements were made at 90 day intervals in order to define the growth curve of each subsample. At 30 months after planting in the savanna area, the UAT 1896-7 subsample showed a higher number of terminal shoots comparing to the other subsamples, and had higher development in height than UAT 1596-7 and UAT 1096-5 subsamples. The UAT 1596-7, UAT 1096-5 and UAT 0796-8 subsamples showed similar terminal shoots values forming a group with intermediate characteristics. Parameters in basal diameter and number of basal shoots, were not significant between the subsamples at 30 months after planting. However, there was more abundant flowering, especially in subsample UAT 1896-7, with 3195 flowers. The UAT 1596-7 andUAT 0796-8 subsamples showed similar values, with 470 and 400 flowers, respectively. The UAT 1796-7 and UAT 1096- 5subsamples presented 338 and 81 flowers, respectively. The subsample URUBU-2 showed no flowering. In the transition savanna/forest area, the UAT 1096-5 subsample showed the best vegetative growth, presenting higher number of terminal shoots, greater height, and early flowering comparingto the other subsamples at 30 months after planting. UAT 1896-7 and UAT 0796-8 subsamples showed no statistical difference from UAT 1096-5 regarding the number of terminal shoots, but showed slightly lower height, with a statistically significant difference. In relation to precocity, peak flowering occurred in January, 30 months after planting, with the UAT 0796-8 and UAT 1096-5 subsamples excelling over others, with 500 and 435 flowers in total, respectively. The experiment Genotype x Environment analysis was considered fixed for genotype (subsamples) and random for environments (areas of study). There was no difference between the two areas for all parameters evaluated including basal diameter (mm), plant height (cm) and number of terminal branches except for the number of basal branches. The interaction among subsamples and environments at 30 months after planting showed similar effects in savanna and savanna/forest transition, showing that the subsamples have stability in both areas.