**1. Introduction**

Rice (*Oryza sativa* L.) is ranked as first in human food crop for more than half of the world's population [1] and economically imperative food crop with nutritional diversification that helps in poverty alleviation. With the intensifications of diverse food demands and living standards of global populations, rice grain appearance and grain quality have become a primary concern for rice breeders [2]. Rice grain quality characters has been grouped into two classes: (i) grain appearance and (ii) cooking and eating qualities. The grain appearance includes kernel length, kernel breadth, kernel length-breadth ratio, endosperm translucency and cooking and eating qualities includes cooked kernel elongation, amylose content, gelatinization temperature (measured as alkali spreading value), aroma and volume expansion. In addition processing qualities, hulling percentage,

milling percentage and head rice recovery are important for market value. Most of the quality traits are complex trait governed by quantitative inheritance.

Generally, Japanese people prefer short and sticky rice, while Indians prefer aromatic basmati rice which elongates when cooked. Indian basmati rice and Thai jasmine rice are highly priced due to their distinctive aroma when cooked and some European countries have led consumers to prefer better quality rice. Due to consumer's demand for better rice quality, rice breeders are striving to develop rice varieties with improved qualities that meet local demand. Basmati varieties has superior quality traits *viz*.

Superfine slender grains, fine cooking quality, pleasant aroma, and lengthwise elongation during cooking and fetched with premium price in the local and global market [3]. The physicochemical and cooking characteristics are the good indicators of grain quality [4, 5]. Most of the consumers prefer rice with soft to medium gel consistency, intermediate amylose content and gelatinization temperature.

Kernel elongation after cooking is an important character of fine rice and most of the rice consumers prefer length-wise elongation. Rice kernels absorb water during cooking and increase in length through swelling of kernels. Breadth-wise increase is not desirable, whereas length-wise increase without increase in girth or a crack on the kernel is a desirable characteristic of high quality rice. In northeast India, cultivated varieties having high kernel elongation might also have originated from this region. The elongation genes might have moved towards both eastern and western parts from the periphery of the centre of origin. Some varieties showed marked elongation in eastern countries such as Burma and Thailand. However varieties in western region with Punjab showed good kernel elongation.
