EFFECT OF NITROGENOUS LEVELS AND PLANT DENSITY ON THE PRODUCTIVITY AND GRAIN QUAILTY OF HYBRID RICE (Oryza sativa L.)

Abstract

Rice (Oryza sativa L.) is definited as a main source of nourishment for man for over 10,000 years and fed a great number of people for a longer period than any other crop. Nowadays, rice is the world's most vital food crop. The grain accounts for 80% of the total calories consumed by Two­ thirds of the human population; its annual yield worldwide is approximately 550 million tons. Fifty countries produce rice. In 2009 growing season, rice was the second most cultivated food grain. The 550 million ton harvest was up 200 mi'Ilion over typical harvests of the 1990s. The total harvested area reached 156 million ha, included 577 thousand ha harvested in Egypt 2009 season (FAO, 2009). While the same year, Egypt recorded the world's highest productivity per ha which was 10.4 tonlha. In Egypt, rice cultivation occupies about 10% of the total cropped area. Rough rice production had grown in Egypt from 6.362 thousand tons in 2005 season to 6.729 thousand ton rough rice production in 2009 (IRRI Statistics, 2009). All that explains the importance of rice crop in Egypt as the most profitable summer crop preferred by a large segment of the population than any other carbohydrates.

Recently, Egyptian government aims to reduce rice fields to 1.1 million feddan (445,154 hectares) from 1.7 million feddan, as a part of a strategy to save irrigation water. As cities expand over agricultural land and the rapidly population growth, more pressure are placed on remaining land to become more productive. The development of modem early high yielding varieties with pest resistance and improved grain quality became the best solution for all formerly problems. Egypt started adopting hybrid rice planting. Hybrid rice research program in Egypt was restarted in1982 (Bastawisi et al., 1998), and by 2005, the program resulted in the development of two promising hybrid rice combinations, SK 2034 H (HRl) and SK 2046 H (HR2), which out yielded the current cultivars by 15-30 % (Bastawisi et al., 2005).

Chaturvedi (2005), in earlier studies, revealed that judicious and proper use of fertilizers can markedly increase grain yield and improve rice quality given the importance of nitrogen fertilization. To gain high grain yield from the rice plant, it is necessary to know what the best dose of fertilizer is suitable for each variety as well as its influence on components of yield and other agronomic parameters such as plant height, lodging ability and superior grain quality