and the Specifications of Dates in the Early and late Ripening Stages

Prepared By:

Agricultural research station
Al hemrania_Northern Agricultural Region

Preface

Date palm is a blessed tree which has linked and deep-rooted in the history of the Arab world since ages.In Response to the sublime directives of the late H.H.Sheikh Zayed Bin Sultan AL Nahyan and his brothers members of the supreme counsel, rulers of the Emirates the Date palm trees attained great care and their number exceeded 20 million trees.

The sublime directives were translated into works of creativity by the senior officials of the agricultural sector headed by the Minister of Environment and Water who instructed to establish the Date palm tree research unit in the northern agricultural region to carry out studies, research and experiments and to get acquired with the obstacles and problems that may face the workers in this field which involves the services and post harvest care.

The publishing of the research results contributed much the preparation and the rehabilitation of farmers to cope with the tremendous development in the techniques of date palm propagation and the related industries or scientific basis which will ensure the sustainable development of agriculture in the UAE.

Abdullah Khalfan Alshariqi

Introduction

Early ripping varieties of dates always get the advantage of obtaining high economical revenues as they reach to the early ripening date stage such as the varieties of vgaal, khatri Gish khasra. Some of late ripping varieties may not reach the stage of ripe date due to the climate conditions, therefore they won't be favorable for consumption or attaining easy marketing hard enough for consumption like Hlali and khsaab varieties.

Chemical and physical methods are used to hasten the ripening stage of fruits through spraying the dates with Ethril during the late stage of ripening. The results of studies which were carried out to treat fruits with viniger, salt solution (11, 10, 1) or by exposing the fruits to the heat or dry hot air proved positive.

The experiment made to find out the metazenic effect on fertilization of some varieties in order to control the earliness of ripening stage. Some of male have positive effect on the earliness of the ripening period as well. Studies made to find out the effect of reducing the number of fruits in the bunches to hasten the earliness of ripening were found positive as well (9, 7, 4).

Therefore it was found necessary to study the effect of covering the bunches directly after being fertilized with punched paper bags to recognize the early ripening of some varieties as well as the late ripening varieties which may not reach to the maturity stage and also the effect of covering the bunches with bags directly after the fertilization of fruits and their physical and chemical specification.

Materials and Methods

The present study was carried out during the agriculture seasons of 1998, 1999 on the early ripping varieties as ngaal, khatri and Gish khasra as well as the late ripping varieties of hlali, khsaab. Five date palm trees were identified and the chosen trees aged 8 years. The palm trees were fertilized with one variety and the bunches were covered by punched paper bags. Bags were tied up together with the holder of the bunch in order to ensure being untied by winds. Fixing of bags continued for 45 days (picture 1).

Picture (1) covering the bunches with punched paper bags directly after fertilizing

The following studies have been carried out as follows:

• percentage of fertilization = number of the fertilized fruits x 100 number of total fruits .
• Five date palm trees were identified each of them of 8 years old. The palm trees were fertilized with one variety and the bunches were covered by punched paper bags. The bags were tide with the holder of the bunch in order to ensure being untied by winds. The bags were kept for 45 days.

2-The natural specification of fruits:

• average weight of fruit and stone (seed)
• Average of size of fruit and stone (seed)
• Average of weight of flesh parts.

3- The chemical specifications of fruits:

• Dissolved solids
• Relative moisture

4- Percentage of maturity which was calculated according to the following equation:

• Percentage of maturity =number of matured fruits –the total (number of fruits x100.

Results and discussions:

Studies made during the agricultural season of 1998, 1999 proved the positive effect of bags on the percentage of fruits as the covered bunched surpassed the uncovered ones (the comparison). The above was referring to the raise of the temperature which surrounded the inflorescences of the covered bunched which was agreed with the attained results of the researchers (5, 6). The results of this research show that the physical and chemical specification of fruits the covered fruits surpassed the uncovered ones.More over, the ripening date of the covered bunches was faster than the uncovered bunches (picture 3).

Picture (2) covered and uncovered bunches the increase of percentage of fertilization show clearly in the covered bunch	Picture (3) right and left bunches were covered ripening was shown clearly in the bunched bags

Recommendations:

It is recommended to cover the bunches directly after fertilizing with punched paper bags and to be kept for 45 days in order to obtain earlier ripening as well to improving their physical and chemical specifications.

References

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