Study of the Floral Differentiation in Two Grape Cultivars “Halwani-Baldi” and self/exo -factors Affecting it

Nofal Al-Radowan 
General Commission for Scientific Agricultural Research-
Homs Research Center
Ba’ath University, Faculty of Agriculture


This study was  carried out at Homs Research Center  on two  grape local varieties, Halwani and Baladi which rearing on arbor -training.
The aims of this  study are:
-Study the time of flower differentiation and influence of self and climate factors on it and effect of self  factors on differented buds .
-Study flower differentiation dynamism, formation and growth winter bud and the stages of differentiation flower beginning from bud bursting to fruitset and formation flower parts.
Flower differentiation of both cultivars (Halwani – Baldi) began early June, 2002 (after fruitset by 4) while in 2003, this was 3 weeks earlier than 2002 (second half of June).
Flower differentiation had finished early August (maturity starting) in 2002, while in 2003 it is one month more early than last year (after fruitset by one month ).
The time of winter bud differentiation related to:
When an optimized accumulation of carbohydrates (especially starch and simple carbohydrates).
There is about 549 thermal units  from buds bursting  in this season.
– There is no effect of the number of light and atmospheric humidity on winter bud differentiation.
– The treatment 6 cans which every one contains 14 buds achieved the higher percentage of differentiated buds, and higher yield and quality.
– The basis eyes to be late for two experimental varieties by the flower differentiation.
– The eyes of two varieties were followed as some dynamism of  flower differentiation.
– The height of flower initiates in Halwani cultivar were longes than Baldi, This height increases from the bottom buds (1 – 4th). This took place according to the apical dominance. This result is consistent with the time of ripening of fruit cluster.
– The fruit cluster would obtained it the height of flower initiate rise 650 micron in the two cultivars, While it this value equals >650 micron the result is small cluster in size, uncompleted type, or it turned to tendril because the two cultivars classified as eastern group which characterized by big cluster and the flower initiates must be too large to from clusters.
– After the flower differentiation in productive buds, the beginning starts differentiation. So, we can distinguish four stages from its formation to swelling.
1- Main axes formation, then it will elongated.
2- Secondary axes formation.
3- Flowerseence sets formation.
4- Scale leaf formation in secondary axes base which enclose flowersence sets.
– The stages of differenietion flower beginning from bud bursting to fruitset divided as following:
1- Temporary stage between swelling and bursting bud.
2- Starting of flower beginning which still correlated to the growth
3- Peak.
4- Secondary and tertiary axes separation.
5- Flower hanger separation and calyx appears.
6- All axis of inflorescence complete it’s formation.
7- Post-opening flower.
8- Fruit set.
Stages (2 -3-4 – 5 – 6) took place before flower opening  while the stage (7) after it.
– Results show that the method of cap dropping in the Halwani cultivar differs from Baldi one, This difference could attributed to the sequence of the formation of the separtial layer in the every petal base. The type of cap at separation and the way of cap hunging by flower pro- separation results also show existence differnces in the type and color of nectarin glands. The way of separation, type of the cap, the way of hanging and the type and color of nectarin glands  play an essential role in the recognizing of  the cultivars.