Floração, frutificação e características físico-químicas de laranja ‘Pera-Rio’ em relação à disposição na copa

Abstract

The objective of this study was to evaluate the time of flowering, fruiting and variation of physico-chemical characteristics of fruits in different crown positions of the orange 'Pera-Rio'. The research was developed in the Matão Heath Farm, 15 km of the BR 174, located 35 km from Manaus. We selected 10 plants of 'Pera-Rio', the crown was divided into four quadrants (Northeast, Southeast, Southwest and Northwest) and three layers (basal, middle and apical) and were arranged in a 4 x 3 factorial, in a completely randomized design with 10 replications. We evaluated the phenological periods with the aid of a phenological scale, corresponding to each marked branch to obtain the sub-periods in days, thermal accumulation (Degree-days) and develop a phenological model that also evaluated fruit growth through the longitudinal and equatorial diameters, and collection of leaf deposition in the weekly period. The flowering period began on 6/11/2010 and ended on 11/27/2010, fruit crops occurred on 7/14/2011, 7/21/2011 and 08/06/2011. The events were associated with climatic data from the Reserva Adolpho Ducke in the period July 2010 to August 2011. The characteristics evaluated were: size, mass, and fruit quality. In sub-periods 3-9 (anthesis to harvest the fruits) found that on the basal layer in the Northeast had a longer duration (304 days) and that it issued a shorter duration (236 days) on the stratum Apical. According to the sub-evaluation periods from anthesis to fruit maturation were required to accumulate thermal 3495.7 GD. The phenological model was divided into floral induction to anthesis with an average of 80 days, flowering to fruit set, with an average of 21 days. The periods were preceded by high temperature, high global radiation, low precipitation, and relative humidity, in July to November 2010. The phase of attachment to the fruits of growth were observed on 11/27 to 07/03/2011, lasting 100 days, this period was marked by a gradual increase in rainfall of 131 mm in November, and a maximum of 531.5 mm in February. In the growth phase to harvest the fruits that had elapsed between 03/07 until fruit harvests of, 07/14, 07/21, and 08/06/2011, were marked by higher temperatures and higher global radiation, it took 8 to 9 months between the periods from anthesis to fruit maturity at harvest of 2010/2011. In the indexes of fruit sets did not have significant differences between treatments. The absolute growth rates of fruits were higher in April, a period of high rain, with the highest average growth in the southwest quadrant 3.08 cm3/month, and 2.35 cm3/month in stratum apical. The lowest growth rates were observed in July, and August 2011, a period of fruit maturation for all quadrants and levels. The leaf dry matter obtained the highest average in November (1.2 ton / ha), which occurred in flowering months, preceded by the period of drought, low relative humidity, high temperature, and global radiation. The fruits located in Northwest and Southeast quadrants promoted greater mass of juice were more succlent, with higher pH, higher soluble solids content and with better color. The fruits of the apical and middle strata had better quality than on the basal layer: longitudinal diameter, equatorial diameter, mass, juice, fewer seeds, and juice color. Based on the results, the arrangement of plants within the row can have influence over the development, and physico-chemical, characteristics of fruits according to different positions in the canopy