Studies on Grain Yield, Physico-Chemical and Cooking Characters of Elite Rice Varieties (Oryza sativa L.) in Eastern India

Forty one rice varieties of different ecologies are evaluated at Central Rice Research Institute, Cuttack to find out varieties having better quality characters and yield. It is revealed that hulling percentage is very good in all the genotypes and ranged from 71.0 (Vanaprava) to 81.0 (Ajay). The milling recovery varied from 62.0 (Vanaprava) to 76.0 (Radhi). The HRR% varied from 43.5 (Kalyani-2) to 68.0 (Pooja). The kernel length is highest in Geetanjali (7.54) and lowest in Nuadhusara (3.88). Kernel length after cooking is very important character and varied from 7.9 (Nuakalajeera) to 12.5 (Geetanjali). Elongation ratio is highest in Nuadhusara (2.07) and Nuakalajeera (2.0) and lowest in Chandan (1.44). Volume expansion ratio is highest in Nua kalajeera (5.25), Nuadhusara (5.15) and lowest in Udaya (3.25). Amylose content is intermediate in all the tested genotypes except Heera and Vanaprava and it ranged from 22.1 (Utkalprava) to 26.1 (Vanaprava). The yield is highest in Rajlaxmi (7100 kg ha) followed by Ajay (6400 kg ha), Satyakrishna (6300 kg ha), Vashadhan (6200 kg ha) and lowest in Tara (2800 kg ha ).


Introduction
Rice is the staple food for over half of the world population and it is ranked as the number one human food crop in world (Itani et al., 2002).More than 90% world rice is grown and consumed in Asia (Tyagi et al., 2004), where as 60% calories are consumed by 3 billion Asians.India is the second most populous nation, stands first in areas, second in production followed and preceded by China.Rice occupies a pivotal place in Indian food and livelihood security system.It provides about 75% of the average calories and 55% of the protein in the average daily diet of the people (Anonymous, 2002).In India, rice occupies 44.6 mha.Grain quality in rice is determined by the factors such as grain appearance, nutritional value, cooking and eating quality (Juliano et al., 1990).The nutritional values and processing properties are very important for overall health of the people and commercial purposes including economy of the rice growers.Quality is very important determinant of market price, consumers acceptance and end users.Consumers preference is based on appearance, milling and cooking processes, grain shape and size.
Good grain quality fetches higher price for the farmers.Demand for better grain quality is increasing in the economically developed and developing countries.Earlier emphasis was given for high yield and insect/disease resistance during varietal development.But now, quality is the important breeding objective in rice breeding programme in all rice growing countries.As unattractive grain character and unsatisfactory cooking quality hampers the acceptance and spread of modern variety, quality improvement receives special emphasis since last one decade.Till today, India has released 705 released rice variety with out testing for quality characters (Thongbam et al., 2010).Now quality characters are considered during variety development and release.So the breeders have given due emphasis for quality characters.Sobha et al. (2008) studied the quality characters of 78 released varieties for India.There after, the quality characters of 28 rice land races of Assam were studied (Das & Borah, 2008).Realizing the importance, Bhonsle and Sellapan (2010) evaluated 22 traditional rice varieties of Goa for their physico-chemical characters.Fifty six high yielding varieties were also studied for quality characters in Kerala (Vanaja & Babu, 2006).Eleven rice genotypes of Faizabad were evaluated for quality characters (Srivastava et al., 2012).Keeping this in view, 41 promising rice varieties of eastern India were evaluated for quality characters to find out better genotypes to be used as donors in breeding programme and popularized among the farmers.

Methods
After three months of harvest, samples were cleaned thoroughly using winnower to remove the chaff and other foreign matters and dried in hot air oven up to 12-14% moisture content.Analysis of all traits were done in two replications.

Physical Properties
Kernel length, kernel breadth and length breadth ratio were measured by dial micrometer (Ramiah, 1969).Hulling and milling were done by using standard rice huller (Satake Thuzja) and rice polisher (Satake TMO5A) respectively.After cleaning and weighing the dehusked kernel (brown rice) hulling % was calculated.Dehusked kernels were polished to remove bran and milling percent was calculated.

Cooking Characters
Water uptake and volume expansion ratio were calculated (Anonymous, 2004;Beachell & Stansel, 1963).Similarly kernel length after cooking and elongation ratio were measured following Azeez and Shafi (1966).The grain yield was recorded on plot basis and converted to per hectare.All the pooled data were analyzed (K. A. Gomez & A. A. Gomez, 1984).
Milling out turn is the measure of rough rice recovery during milling.It is one of the important properties to the millers.The rice millers prefer varieties with high milling and head rice recovery, where as consumers preference depend on cooking and eating qualities (Merca & Juliano, 1981).The milling recovery is lowest in Vanaprava (62.0) and highest in Radhi (76.0).Out of 41 varieties, 29 varieties showed high milling out turn i.e.>70%.Most of the upland varieties showed low milling out turn.
Head rice recovery is the proportion of whole grains in milled rice.It varies depending on the variety, grain type, cultural practices and drying condition (Asish et al., 2006).More emphasis should be given to head rice recovery than to total rice yield since it is more important commercially and it is easier to improve (Jenning et al., 1979).HRR% is a heritable trait although environmental factors and post harvest handling are known to break the grain during milling (Fan et al., 2000).HRR% varied from 43.5 (Kalyani-2) to 68.0 (Pooja).Out of 41 varieties, 22 varieties are having better HRR% i.e >60.0.The upland varieties are having low head rice recovery i.e <60.0%.The scented and hybrid varieties are also having very good head rice recovery percent.

Chemical Characters
The alkali spreading value (ASV) gives the estimate of gelatinization temperature and it varied from 3.0 (Uday) to 7.0 (Indira) indicating very wide variability.The quality and quantity of starch and Gelatinization temperature strongly influence the cooking quality.The gelatinization temperature affects the water uptake, volume expansion ratio and linear kernel elongation (Vanaja & Babu, 2003).Alkali spreading value gives an idea for gelatinization temperature.
Water uptake is very important character because it is directly related to energy consumption.It is lowest in Tapaswini (97.5) followed by Ratna (110), , Heera (115) and Tulsi (125) and highest in Tara (330) following Indira (302.5),Chandrama (297) and Shaktiman (197.3).More water uptake require more energy for cooking so less water uptake is good for low income consumers.The amount of water uptake during cooking process is associated with the appearance of cooked rice (Fan et al., 2000).
It is influenced by genetic factors and environment specially temperature during ripening (Dela Cruz et al., 1989).