The present investigation was undertaken during both 2012/2013 and 2013/2014 growing seasons on
"Etmani" cv. guava trees to study the effect spraying some chemicals substances (urea, GA3 and PP333) as
well as hand defoliation on fruiting parameters (fruit set and productivity of tree per kg) and fruit
characteristics either physical properties such as fruit weight, volume, length, width, fruit shape index and
fruit firmness) or fruit chemical characters (TSS %, total acidity %, TSS/acidity ratio, total sugars content and
vitamin C content). The objective of this study was turned the summer yield of guava fruits to late crop
"winter crop" to obtain fruits of good quality and to help farmers to obtain good income by high prices of
guava yield. Data obtained indicated that, all investigated treatments under study significantly decreased yield
(kg/tree) as compared to the control except with sprayed trees with PP333 at 500 ppm treatment in the two
seasons of study. Whereas both treatments induced the highest significant increase of tree yield, however
hand defoliation treatment exhibited significantly the lowest value of tree yield (kg/tree). Moreover, results
indicated also that, all studied fruit physical properties (fruit weight, volume, length and width) were induced
a positive relationship with GA3 sprayed trees. Meanwhile, both fruit firmness and fruit shape index were
statistically increased by trees sprayed with PP333 treatments, since the least significant values of all fruit
physical properties induced by trees treated with hand defoliation treatment. In addition, data obtained
revealed that, chemical investigated treatments under study were significantly and a positive effect in most
fruit chemical properties as compared to the control treatment. However, trees sprayed with (GA3, PP333 and
urea) resulted in significantly increase in total sugars content, vitamin C content, TSS/acid ratio and TSS % as
well as total acidity %, respectively. Whereas, both control and hand defoliation treatments exhibited the
lowest significant values of these fruit chemical properties under study. Generally, it could be concluded that,
the different investigated spray treatments of chemical substances in this study were improved the fruit
quality either physical or chemical properties of guava fruits. Also, the higher concentrations of studied
treatments were the most effective for improving the fruiting parameters and fruit quality of "Etamani" guava
trees. |
