ESPINOLA SOBRINHO, J.; http://lattes.cnpq.br/9926820581274995; ESPÍNOLA SOBRINHO, José.
Résumé:
This research work was conducted at Mossoro-RN in 2001/2002 to devise
alternatives for increasing the productivity and improving the quality of Tommy Atkins
mangoes, based on the influence of crown architecture, solar radiation, and air temperature.
To study the penetration of the solar radiation in the crowns it was utilized 30 trees which
underwent crown thinning by different methods. Sensors were placed at selected sites for
measuring the global, infrared, and photosynthetic active radiations inciding on the top and
base of the crowns, as well as the reflected radiation on the crown top, besides the
temperature near the fruits. Data were obtained at each time second through automatic data
collecting systems. At harvest each tree crown was subdivided in quadrants and the fruits
collected separately. The fruits were stored in cold chamber for color analysis and
determinations of soluble solids content (SSC), titratable acidity (TA), and pH at zero, at 24
and 31 days post-harvest. The maximum albedos were provided by the 2V-thinned (19.7%)
and pyramidal (19.2) architectures. Control, V-thinned, and 4V-thinned architectures did
not differ significantly with regard to the albedo and the cup-shaped architecture was the
least reflective. The amount of radiation that reached the crown base varied significantly
depending on the crown architecture, 22.0% in the control to 65.0 in the cup-shaped. Short
wave radiation inciding on the crown base in the cup-shaped architecture was threefold that
at the base of the control. The infrared radiation inciding on the crown top averaged about
48.2% of the short wave radiation, while the reflected varied from 28.9% in the 4V-thinned
to 34.0% in the pyramidal architecture. As the control architecture screened only 43.9% of
the top-inciding infrared radiation, the V-thinned, cup-shaped, and 2V-thinned architectures
allowed pass through 79.4, 74.3, and 70.3% of that radiation, respectively. Photosynthetic
active radiation (PAR) reached amounts of 7.0 to 12.0 MJ.m"2 d"1, which represent about
47% of the inciding short wave radiation, almost entirely absorbed by the crowns. The cupshaped
architecture provided the highest PAR transmittance level (38.2%). The least PAR
transmittance levels were recorded in crowns with 4V-thinned, pyramidal, and control
architectures. The ultraviolet radiation varied between 0.8 and 1.2 MJ.m"2.d_1, which
correspond on an average basis to 4.9% of the inciding short wave radiation. The maximum
and minimum UV transmittances were recorded in the 2V- (90.1%) and 4V-thinned crowns
(4,9%), respectively. There was a good correlation between inciding short wave radiation
(Rg) and radiation balance (Q*). The temperature near the fruits was always approximately
1°C greater than that of air, but in the control architecture crowns that temperature
practically equaled air's, while in cup-shaped crowns the average At was 2°C higher. Trees
with the 4V- and V-thinned crowns were the most productive (about 16 ton/ha), reaching
23% above the region average. All architectures tested yielded better than the control, with
only 9.5 ton/ha (27% below the region average). The most productive quadrants were SW
and NE. In the control was recorded the greatest natural fruit fall index (34.5%) and the
cup-shaped crowns had the greatest loss due to internal collapse (87.0%). Trees with 4Vthinned
and pyramidal crowns produced about 48% export fruits against 38% of the
control. According to the post-harvest analyses there were increases of SSC and pH in
fruits from all architectures along time storage range. Fruits from all architectures had the
average TA drastically decreased until the 31s t day of storage. Type of architecture and
quadrant, or their interactions, did not affect significantly SSC, TA, and pH. The most
effective treatment with regard to the development of the internal and external fruit colors
was the NW quadrant in V-thinned crowns.
