Khah Ni 117, a Highland Rice Variety

Abstract

Thailand topography consists of about 53 percent (67.2 M rai) highlands with elevation above 500 m mean sea level located in 20 provinces in northern and central regions. Most of the areas are inhabited by ethnic group populations who rely mainly on agriculture and rice cultivated for consumption. There is always problem of inadequate amount of rice for consumption because of low yield due to seed impurities of various traditional rice varieties. Therefore, a varietal improvement project was conducted to develop a pure line with high yield and suitability for terrace cultivation. Samples of Khah Ni rice cultivars were collected from farmers' fields in Phrao district, Chiang Mai province and grown for pure line selection. Research have been carried out during 2004 to 2020 through the following crop improvement steps, i.e., varietal observation, yield trials, evaluation on rice disease and insect pests, response to N fertilizer application, analyses for grain physical and chemical quality, milling quality and cooking and eating quality, analysis of nutritional value and farmers' acceptance evaluation. The promising line was subsequently approved by the Varietal Releasing Committee of the Rice Department to be a certified variety, "Khah Ni 117". It is a highland, non-glutinous and photoperiod-sensitive rice with flowering date (50% flowering) about 4^th to 24^th October and harvesting date around 10^th to 24^th November. It has erect plant type, intermediate culm strength, 143.0 cm height, green colored blade with purple leaf tip, slow leaf senescence, 53.9 cm leaf length, 1.7 cm leaf width, 32.4 cm flag leaf length, 26.7 cm panicle length, well-exserted panicle and high seed fertility with 148 fertile seeds per panicle. The average farmer field yield was 517 kg/rai. It has straw with brown stripe colored paddy and white dehulled grain, large chalkiness, low amylose content (15.10 percent), non-aromatic cooked rice, 10.2 percent protein content in brown rice, good milling quality and no response to N fertilizer application. Remarkable features of Khah Ni 117 are high yield potential (783 kg/rai) in a paddy field at 700-1,000 m above mean sea level, high nutritional value, prebiotic activity and moderate resistance to leaf blast. It is recommended for terrace cultivation. Caution should be taken as this variety is susceptible to white-backed planthopper and gall midge.