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Abstract
V. SUMMARY AND CONCLUSION
In this regard two experiments included in the present dissertation were dealing to investigate flowering behavior; fruiting and vegetative growth, as well as fruit characteristics and some chemical compositions of Balady lime (Citrus aurantifolia) trees in response to soil type and various GA3 foliar spraying dates and PP333 treatments comparing with water spray (control) during two experimental seasons (2004 – 2005 and 2005 – 2006).
V.I. Experiment 1:
This experiment was devoted to study the effect of different combinations between soil type and GA3 foliar spraying dates on flowering, fruiting and fruit quality of Balady lime.
V.I.1. Flowering and fruit set:
A- Specific effect:
With regard to specific effect of GA3 spraying date, both flowering and fruit set % followed the same trend. Herein, control (water spray) resulted statistically in the highest values of two flowering measurements (No. of flowers & percentage of control flowering) and fruit set %, while the reverse was true with GA3 sprayed branch on Nov. 7th during two experimental seasons where spring flowering was completely absent. Moreover, other GA3 spray treatments came in between the aforesaid two extremes, however both flowering measurements (No. & percentage of spring flowering) were gradually increased as date of GA3 spray delayed.
As for the specific effect of soil type, both flowering and fruit set % were higher in sandy soil than those of clay soil. However differences were more pronounced in flowering than fruit set%.
B- Interaction effect:
Data obtained during both seasons revealed that specific effect of each investigated factor (GA3 spraying date & soil type) was directly reflected on their combinations. Herein, water sprayed branches (control) of Balady lime trees grown in sandy and clay soils ranked statistically 1st & 2nd respectively as both flowering and fruit set % measurements were concerned. On the contrary, GA3 sprayed branches on Nov. 7th of Balady lime trees at either sandy or clay soil failed completely to flower. In addition, other combinations were in between with a general tendency showed that those of the latest GA3 spraying date (Dec. 5th) had relatively higher flowering value as compared to other members of such intermediate category.
V.I.2. Fruit retention and yield:
A. Specific effect:
Specific effect of GA3 spraying date revealed obviously that water spray (control) showed statistically the greatest values of three evaluated measurements. However, the reverse was found with Nov.7th GA3 sprayed branches, where neither retained fruits nor mature ones were observed for branches of such depressive spray treatment during both experimental seasons. In addition, other investigated GA3 spray treatments (from Nov. 14th till Dec.5th) were in between the abovementioned two extremes with a relative tendency showed that values of 3 measurements slightly increased as GA3 spraying date delayed. However, the differences between four members of such intermediate category were still insignificant during two experimental seasons.
As for the specific effect of soil type, difference between two soil types were too slight to be taken into consideration from the statistical point of view during both experimental seasons.
B- Interaction effect:
Data obtained during both experimental seasons revealed that specific effect of each investigated factor reflected directly on their combinations. Herein, the control (water sprayed branches five times weekly from Nov. 7th till Dec. 5th) of Balady lime trees, in either clay or sandy soil) exhibited statistically the greatest values of both retained fruits (number & percentage) and yield (mature / harvested fruits). However, the combination of clay soil farm tended to exceed statistically that of sandy soil farm as two fruit retained measurements (No. & %) were concerned, while difference in yield didn’t reach level of significance during two seasons.
On the contrary, both combinations of Nov. 7th GA3 sprayed branches were significantly the inferior (regardless of soil type), whereas their fruits failed completely to retain and consequently no mature fruits were presented at harvest during two experimental seasons. In addition, other combinations were in between the aforesaid two extremes.
V.I.3. Fruit quality :
V.I.3.1. Fruit physical properties:
A- Specific effect:
With regard to the specific effect of GA3 spraying date, eight investigated fruit physical characteristics followed 3 different trends as follows :
1- Average fruit weight (g), size (cm3), polar diameter (height), equatorial diameter (width) and fruit juice volume (cm3) followed typically the same trend. Herein, four spraying dates on either Nov. 14th, 21st, 28th or Dec. 5th resulted significantly in increasing values of these five fruit physical characteristics as compared to control (water spray) during both experimental seasons.
2- Both fruit peel thickness and fruit shape index (polar diameter : equatorial diameter ratio) showed slightly response to GA3 spray treatments which did not reach level of significance during two experimental seasons.
3- Number of seeds per fruit followed a firm trend showed that all GA3 spray treatments decreased significantly seeds number as compared to control. However, the number of seeds was relatively increased as GA3 spraying date delayed, but differences were too slight to reach level of significance as four later spraying dates were compared each other during two experimental seasons.
As for the specific effect of soil type, the response of all (eight) investigated fruit physical characteristics was too few to be taken into consideration from statistical stand point during two seasons of study, where differences could be safely neglected.
B- Interaction effect:
Data obtained during both seasons displayed that the specific effect of two investigated factors (GA3 spray treatments & soil type) reflected directly on their combinations. Herein, the average fruit weight, size, dimensions and fruit juice volume exhibited their greatest values by the different GA3 treatments applied on Nov. 14th until Dec. 5th which significantly exceeded the analogous ones of the control (Water spray), regardless of soil type. Meanwhile, both fruit physical characteristics of fruit peel thickness and shape index didn’t respond to various combinations between two studied factors (soil type & GA3 spray treatments). In addition, number of seeds per fruit showed that the highest number always was in concomitant to the water spray treatment (control), regardless of soil type from statistical point of view.
V.I.3.2. Fruit chemical properties:
A- Specific effect:
With regard to specific effect of GA3 spraying date, fruit juice TSS%, acidity % and TSS / acid ratio did not significantly respond to all investigated spray treatments. whereas, all GA3 spray treatments (except Nov. 7th) did not significantly differ than control (for such 3 fruit juice content) during both experimental seasons. Meanwhile the specific effect of GA3 spray treatments on fruit juice V.C. content revealed that all GA3 spray treatments (except on Nov. 7th) increased it significantly over control during two seasons.
As for the specific effect of soil type, no noticeable influence on all included fruit juice chemical properties (TSS, acidity %, TSS/acid ratio and / V.C. content).
B- Interaction effect:
The specific effect of two investigated factors reflected on interaction effect of their combinations. Anyhow, no evident difference was detected in TSS%, acidity % and TSS/ acid ratio. However, with vitamin C. content, it was clear that water sprayed branch (control) induced fruits with the lowest value of V.C. content, especially in fruits of clay soil farm.
V.II. Second experiment:
V.II.I. Flowering :
A. Specific effect :
Data obtained revealed that, sandy soil exceeded clay soil, besides pp333 resulted in increasing number of autumn flowers especially in sprayed branches on two earlier spraying dates (Oct.30th & Nov.7th ) and ( Nov.7th & 14th ). Moreover, it could be generally concluded that two conflicted trends were detected regarding the response of spring and autumn flowering to GA3 spray . Herein, spring flowering was decreased by GA3 spray, especially on ( Oct. 30th & Nov. 7th ) and ( Nov.7th & 14th ) where the spray flowers were completely absent, but the reverse was true with autumn flowering. Taking into consideration that the total number of flowers for both spray and autumn flushes together was the highest with water sprayed lime trees ( control ).
Meanwhile, with regard to specific effect of two other investigated factors, it is quite clear that total number of flowers was significantly higher in sandy soil and PP333 application were concerned, respectively.
B. Interaction effect:
Obtained data revealed that specific effect of each investigated factor was directly reflected on their interaction effect. Herein, the highest total number of flowers was significantly in closed relationship to spring flowering for the unsprayed scaffolds with GA3, especially of Balady lime trees in sandy farm when PP333 was applied the reverse was true with the spring flowering of GA3 sprayed scaffolds on 2 earlier dates (Oct.30th & Nov.7th) and (Nov.7th & 14th) where flowering was completely absent at such flush, regardless of soil type and PP333 application. In addition, other combinations were in between with relatively variance depended on flowering flush GA3, PP333 application and soil type.
V.II.2. Fruit set and retained fruits percentages:
A. Specific effect:
Data obtained during both seasons revealed that both fruiting measurements didn’t respond to three investigated factors except for spring flowering flush whereas flowering didn’t take place.
B. Interaction effect:
Data obtained during two seasons showed that variations was a real reflection of absence of specific effect for 3 investigated factors. whereas, all combinations showed significantly the some value for each fruiting measurements (set % and retained fruits %) except these of spring flush for GA3 sprayed scaffolds on two earlier dates (Oct.30th & Nov.7th) and (Nov.7th & 14th). (regardless of two other investigated factors).
V.II.3. Yield:
A. Specific effect :
Data obtained revealed that harvested fruits of spring flowering were the greatest for control ( water spray ), while the reverse was true for GA3 spray or either (Oct.30th & Nov.7th ) or (Nov.7th & 14th ) where the sprayed branches had spring flowering. On the other hand, GA3 spray treatments increased significant by the autumn fruiting, while the earlier two spraying dates were the most effective than three other GA3 spraying dates.
As for the specific effect of either pp333 application or soil type were significant absent .
B. Interaction effect:
Water spray induced significantly the highest yield resulted by spring flowering associated with the least fruits of heist autumn flowering. On the other hand, GA3 sprayed branches showed the highest yield of autumn flowering associated with either no spring fruiting for (2 GA3 spray at Oct.30th & Nov.7th and Nov.7th & 14th) or a relative comparable yield of spring fruiting for 3 GA3 spraying dates (Nov.14th & 21st), ( Nov.21st & 28th ) and ( Nov.28th & Dec.5th ).
V.II.4. Fruit quality:
V.II.4.1. Fruit physical characteristics:
In this regard fruit average weight, size, dimensions (height & diameter), juice volume, fruit peel thickness and number of seeds per fruit were the investigated fruit. Physical properties to specific and interaction effects of 3 factors under study (GA3, PP333 application and soil type).
A. Specific effect:
The response showed three conflicted trends were detected with these investigated measurements. Herein, GA3 spray increased average fruit weight, size, both dimensions (height & diameter), juice volume and fruit peel thickness. While, the reverse was true with number of seeds per fruit, where GA3 spray decreased it significantly below control. On the other hand specific effect of two other investigated factors (soil type and PP333 applications) was significantly absent for and investigated fruit physical properties.
B. Interaction effect:
Data obtained during both seasons exhibited that variances were a real reflection of specific effect for 3 investigated factors. Herein, the greatest values of (fruit weight, size, dimensions, juice volume and rind thickness) were significantly coupled with those combinations representative of GA3 spraying dates (exception two earlier dates for spring flowering flush), regardless of soil type and PP333 was applied or not for two flowering flushes, while the opposite was farmed with water sprayed branches (control). On the other hand with the number of seeds per fruit the trend took the other way around. whereas, the combinations of control showed significantly higher number of seeds per fruit as compared to GA3 combinations regardless of soil type and PP333 application.
V.II.4.2. Fruit chemical properties:
Fruit juice acidity, T.S.S.%, T.S.S./acid ratio and ascorbic acid contents were the investigated trends.
A. Specific effect:
GA3 spray significantly decreased fruit juice total acidity but significantly increased T.S.S.%, T.S.S./acid ratio and fruit juice ascorbic acid content as compared to control (water spray). On the other hand, specific effect of two other factors (soil type & PP333 application) was significantly absent to all investigated fruit chemical properties.
B. Interaction effect:
The highest acidity % associated with the least T.S.S.%, T.S.S./acid ratio and V.C. content was significantly coupled with water sprayed scaffolds, while the reverse was true with GA3 combinations (regardless of soil type & PP333 application.
V.II.5. Vegetative growth:
In this regard number of shoots per branch, average shoot length, total number of leaves per shout and average leaf area of Balady lime trees were the investigated four vegetative growth measurements regarding the response to specific and interaction effects of soil type, GA3 spray treatments PP333 application and their combinations.
A. Specific effect:
Data obtained during both seasons revealed that four growth measurements increased significantly by all GA3 spray treatments. However, three trends were detected as the specific effect of PP333 application was concerned. Hence, number of shoots was significantly increased by PP333 application, while the reverse was true with both average shoot length and total number of leaves per shoot where PP333 application statistically showed an obvious decrease in this regard. Meanwhile the specific effect of PP333 application was completely absent with average leaf area.
As for the specific effect of soil type, it was clear that clay soil exceed sandy soil in this respect.
B. Interaction effect:
Data obtained during both seasons revealed generally that all combinations of GA3 spray particularly of Balady lime trees grown in clay soil without PP333 application exhibited the greatest values of most vegetative growth measurements. However the reverse was found with those of water sprayed trees (control) regardless of soil type and to great extent PP333 application.
V.II.6. Nutritional status (leaf mineral composition):
In this regard leaf N, P, K, Ca, Mg, Fe, Mn, and Zn content of Balady lime trees were the eight investigated nutritional status in response to specific and interaction effects of GA3 treatments soil type, PP333 application and their combinations.
With regard to specific effect of GA3 spraying dates, data obtained during both seasons displayed that variances were too slight to be taken into consideration with leaf N, P, K, and Fe content, while with Ca, Mg, Mn, and Zn GA3 spray resulted in significant increase than control.
As for the specific effect of soil type, it was quite clear that variations to some extent were relatively slight except with leaf Ca, Mg, and Zn content, where two conflicted trends were found. Herein, sandy soil increased significantly leaf Ca and Mg content than sandy soil, while the reverse was true with, leaf Zn content.
Referring the specific effect of PP333 application, it could be safely concluded that three conflicted trends were detected. Herein, with N, P, K, Fe, Mn, and Zn no considerable response was observed. While with both Ca and Mg two conflicted trends were found, where Ca was significantly higher in leaves of trees grown in sandy soil and the opposite was true with leaf Mg content.