Hamed Doulati Baneh; Hekmat Jafari; Rasul Jalili Marandi; Rahim Abdolahi
Abstract
Introduction: The basic characteristic of modern table grape production is its adaptation to the requirements of the market aiming to improve grape quality, such as equal cluster size, equal size and shape of the berry, and equal coloration of all the berries in the cluster. Furthermore, an important ...
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Introduction: The basic characteristic of modern table grape production is its adaptation to the requirements of the market aiming to improve grape quality, such as equal cluster size, equal size and shape of the berry, and equal coloration of all the berries in the cluster. Furthermore, an important attribute of the grape berry quality is seedlessness. Seedless cultivars are characterized with small berries, which can be increased by using some management techniques. Plant hormones may play an important role in the growth and development of grape berries. Gibberellic acid (GA3) is known to stimulate development of parthenocarpic fruit in grapes and other fruits. The exogenous pre-bloom application of GA3 to grapevine is commonly used to induce seedlessness, accelerate early ripening, and enhance berry size in seedless cultivars. Although there are a large number of studies on seedless grape varieties, no previous research has been performed on the effect of GA3 on the seeded grape cultivars. Differences in the types of berry set affect the growth of berries and their size. It is well known that there is an important relationship between seed development and berry growth, which has been attributed to hormones such as auxins, gibberellins and cytokinins.
Materials and Methods: To study the effects of 100 mg/L pre-bloom (7 and 14 days before blooming) GA3 application on the induction of seedlessness and some berry and cluster characteristics of three seeded Iranian cultivars, Qzl ouzum, Rish babab Qermez and Khalili Qermez, this research was conducted as a factorial experiment based on Randomized Complete Block Design (RCBD) with five replications. The vines of each cultivar were selected in the vineyard of Horticultural Research Center in West Azarbaijan Agriculture and Natural Resources Research Center, Urmia, Iran. The vines were 13 years old and bi-lateral cordon system had been used as their training system. Pollen germination test was performed at the time of flowering, and several qualitative and quantitative traits including fruit set percentage, cluster length, rachis fresh weight, number of shot berries, number of seedless berries in clusters, the average weight of seedless berries, length of pedicle, berry weight, total soluble solids (TSS) and pH were measured.
Results and Discussion: The results of the study showed that GA3 at 100 mg/L showed significant difference from control regarding pollen germination rate, fruit set percentage, length of cluster and rachis, number of shot berries, weight and number of seedless berries, length of pedicle, weight of berry and TSS. Pollen germination was reduced in those cultivars treated with GA3 but the responses of cultivars were different. Gibberellin caused an increase in cluster length, but the rate of increase in Rish baba and Qzl ouzum was greater than Khalili. In terms of inducing seedlessness in berries, GA3 caused greater effect in Qzl ouzum than Rish baba and Khalili Qermez. The greatest seedless berries weight obtained with the treatment of GA3 spray 7 days before blooming in Qzl ouzum, although the number of seedless berries in this cultivar was fewer than other cultivars. The difference in berry number per cluster between clusters receiving GA3 pre- vs. post-anthesis appeared to consist largely of seedless berries. Perhaps, GA3 stimulated non-fertilized or otherwise nonviable fruits to be retained. The longest pedicle observed in Qzl ouzum treated with 100 mg/lit GA3 14 days before blooming, while Khalili Qermez had the shortest pedicle. In all the cultivars, treatment with GA3 caused an increase in the average length of pedicle. The content of total soluble solids (TSS) in fruits treated with GA3 was higher than control. Gibberellic acid promotes cell division, stimulates earlier flowering, increases the size and yield of fruits, and induces seedlessness in seedless cultivars. The effect of GA3 depends on variety, concentration and time of application.
Conclusion: In conclusion, application of GA3 at 100 mg/lit increased fruit set and seedless berries. The increased number of seedless berries was also noticed when GA3 applied at 100 mg/L. In general, GA3 application before flowering in Qzl ouzum, Rish babab Qermez and Khalili Qermez cultivars produced shot berries and seeded berries, and repeated GA3 application after fruit set can resulted in seedless berries with an acceptable size. More research is needed to establish guidelines for the proper use of GA3 for production of seedless berries from the studied seeded cultivars.
Hamed Doulati Baneh; Narjes khatoon Abedi; Tooraj Jadidi
Abstract
Introduction: Before a new vineyard construction, in addition to collecting detailed data on climate, soil and planting area, some other considerations like selection and understanding the principles of quality and quantity in terms of agronomic traits and physiological characteristics of the product ...
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Introduction: Before a new vineyard construction, in addition to collecting detailed data on climate, soil and planting area, some other considerations like selection and understanding the principles of quality and quantity in terms of agronomic traits and physiological characteristics of the product should be made. Among grape varieties grown in anorchard, some self-fertile and male sterile cultivars (female physiological) are present. Without suitable pollinating, varieties in the vineyard, is not accessible for semi-fertile or sterile ones with high quality and quantity and will notbe sufficient.Therefore the identification of sterile varieties, the best pollinizers and fruit growth and phenological stages is essential. Qzlouzum is one of commercial seeded cultivars in West Azerbaijan province whichis suitable for storage and delivering to domestic and foreign markets forout of season because of nice red color and thick skin and late ripening.These favorable properties for sale with high prices is also one of the otherbenefits that have led to the interest of the farmers every year to increase the acreage of the cultivation. Preliminary studies showed that Qzlouzum cultivar is a physiological female and needs cross pollination for fruitset. This study aimed to investigate the complete botanical characteristics, flower sexuality, pollen germination and determine the phenological stages (especially fruit growth stages).
Materials and methods: Based on grape descriptor, morphological characters of 10 vines of Qzlouzum grape cultivar at different stages from bud break to dormancy was studied in Horticultural Research Station in 1390 in Urmia(Kahriz). To calculate the growing degree days (GDD), daily temperature above 10 ° C was obtained from the meteorological station of Agriculture faculty in Kahriz-Urmia. Pollen germination rate was tested in both liquid and solid growth medium. In order to study the changes in a number of qualitative and quantitative traits, TSS (total soluble solids), TA (titrable acidity), pH, berry weight and diameter, seed length and weight from the beginning of the berry formation to harvest time of clusters in 15-day interval were measured.
Results and discussion: The results of this study showed that flowers of Qzlouzum are female with reflexed stamens. The results also determined that none of pollens germinated on both liquid and solid media culture. Based on reflexed stamens and none pollen germination, Qzlouzum grape cultivar proves to be male sterile (physiological substance). This cultivar needs 1483 degree days (above 10°C) from bud break till ripening. The changes in TA and TSS were reversed. Amount of acid reduced and sugar content increased with time and berry development. Veraision period was approximately started 55 days after full bloom. At this stage, which is also known as berry softening, acid concentration is reduced and the amount of sugar was increased. Acid content and pH of the fruit were opposite together and by reducing the amount of acid, the pH levels increased. Several studies have confirmed that after changing the color of the grape varieties,sugar can often increase. Conversely, acid reduction in berries is the first happensbefore color change in berries. The berry weight and size changes were described as Double Sigmoid Curve. In the first phase, berry diameter and weight increased rapidly and lasted 60 days. In the second phase or delay phase, berry weight and diameter changedvery slowly while seed weight reached themaximum in this stage. After this phase, the third phase which was associated began with veraision, sugar content increased and the amount of aciddecreased. At this stage berry reached its maximum size and weight.
Conclusion: Uniform planting of Qzlouzum red grapes is not recommended because of male sterility and suitable pollinizers should be used. Male sterility, without emasculation will be suitable for grape breeding programs. In areas with short growing season, if the total heat has not beensupplied, berries of this cultivar will ripe late and sugar contentand color intensity will decrease and will notproducedesired and marketable product. Phenological stages duration is highlydependent on factors such as cultivar, environment and location. Genetic factor also isparticularly important in determining the time of ripening. Qzlouzum is a late ripening grape cultivar and without sufficient thermal requirements, the ripening process will not occur completely.
