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Abstract
INTRODUCTION
Egypt has successfully main tend its sugar production over a period of nearly 1400 years , following sugarcane introduction during the seventh century of this era. The average annual production nowadays approximates 1.2 million tons of sugar from almost 327 thousand feddan*. It contributes about 74% of total sugar production per year in Egypt.
Sugarcane is the most sugar crop in the world as well as in Egypt. The productivity of some sugarcane verities deteriorates in cultivation over a period of time due to unfavorable conditions like soil pathogens and deleterious virus infections. New sugarcane varieties are needed allover most sugarcane growing areas in Egypt due to wide spread cultivation of GT54-9. Therefore, induction sugarcane plants to flowering is required for breeding Program which is an important step in the variety development program to build up new highly producing varieties as well as for keeping the productivity of the standard varieties high as long as possible.
Flowering of sugarcane is primarily a photoperiod response , but other internal and external factors are known to play a role in floral initiation and inflorescence development, These factors include soil moisture, growth regulators, relative humidity, light quality, soil type, maturity for flowering, latitude and temperature.
The present investigation was carried out to study the effect of two factors on flowering of some sugarcane varieties. These factors are documented as vital for sugarcane tassel development; the first is the soil moisture level as previously known from literatures that adequate moisture is critical for induction, tassel development, time of tassel emergence and seed set Moore and Nuss (1995). While, the second is growth regulator such as gibberellic acid (GA3), the most widely available compound, which commercially, produced by fungal cultures and it is the purified natural products that are applied to plants. Generally, gibberellic acid (GA3) is used, because this is the only gibberellin obtainable in commercial quantities, and it used to increase sugarcane yield: GA promotes the elongation of sugarcane stalks with no change in the sugar concentration, so that the net yield of sugar is increased. Also, significant ripening activity was attained with some sugarcane varieties within NO3 and GA regimes highly favorable to growth and may be enhance flowering apices of sugarcane plants Moore et al. (1986).
Thus, the final aim of this work is to optimizing flowering by maximizing, accelerating and/or delaying the responded plants percentage of possible flowering varieties to synchronizing florescence periods of desired ones.
* Sugar Crops Council 2006