Abstract
Correction : Due to an error in the formatting of this paper, the incorrect Introduction was included in the PDF. On 1 September 2015, the Introduction to this paper was replaced with the correct version. Our apologies to the authors of the paper for this error – Editors.Rice (Oryza sativa L.) is the most important food crop of the developing world and belongs to family Poaceae (Graminae). This experiment was conducted at Regional Rice Research and Development center, Bombuwala with the objective of evaluating grain density, yield and agronomic characters of some selected rice genotypes with five new breeding lines and five improved varieties. The new breeding lines 09-892, 09-897, 03-1198, 09-1054-1, 09-1063-3 and the improved varieties Bg 358, Bg 359, Bw 363, Bw 364 and At 362 were cultivated in randomized complete block design with three replicates. After land preparation, the field layout was prepared and then the seeds were broadcasted. Observations of yield and agronomic characters were taken at their corresponding stages of the plant. The variety Bw 364 and 09-1063-3 new breeding line had significantly long culm length and panicle length than other varieties. But 09-892 breeding line with intermediate culm showed a lodging problem in the field. New breeding line of 09-1054-1 showed early flowering than other varieties and it deviated from 3½ month aged group flowering. New breeding line of 09-892, 09-897 and 09-1054-1 took shorter time for maturity. The variety Bw 364 (2.6 g) had significantly higher hundred seed weight than other varieties. Numbers of spikelets/panicle did not vary significantly with treatments in the experiment. The variety At 362 (16.3%) and the new breeding lines 09-897 (25.6%), 03-1198 (26.3%) had the lowest spikelet sterility percentage and Bw 363 (40%) showed the highest spikelet sterility percentage in the trial. High density grain percentage significantly varied among the tested genotypes ranging from 45 to 68%. The highest high density grain percentage was shown by Bg 358, Bg 359, Bw 364, At 362,09-892,09-897 while 03-1198 and 09-1054-1 had the lowest high density grain percentage. Among the improved varieties, Bw 364 (5.3 t/ha) and At 362 (5.1 t/ha) showed the highest yield in the trial whereas the new breeding lines 03-1198 (4.1 t/ha) showed the highest yield. Hence, 03- 1198 new breeding line can be selected for adaptability tests and it promises to proceed in the varietal selection programme to become a recommended variety.Journal of the University of Ruhuna 2013 1(2): 19-22
Highlights
Rice (Oryza sativa L.) is one of the world’s main staple crops with nearly 2.5 billion people depend on it as their main food (FAO, 2004)
Some physiological studies have reported the possibility of increasing grain yield potential through increase in the number of high density (HD) grains
Studies in the plant physiology department of IRRI (International Rice Research Institute) in the past years showed the possibility of increasing grain yield potential through increase in the number of high density grains (Vergara et al, 1990)
Summary
Rice (Oryza sativa L.) is one of the world’s main staple crops with nearly 2.5 billion people depend on it as their main food (FAO, 2004). The main contributory factor for increasing rice production is the high yielding rice varieties. During the past three decades, plant breeders have greatly contributed to the development of high-yielding crop varieties to meet the food needs of the growing population. The ultimate goal of crop breeding is to develop varieties with high yield potential and desirable agronomic characteristics. Some physiological studies have reported the possibility of increasing grain yield potential through increase in the number of high density (HD) grains. Studies in the plant physiology department of IRRI (International Rice Research Institute) in the past years showed the possibility of increasing grain yield potential through increase in the number of high density grains (Vergara et al, 1990). Selection for varieties with highest HD grain percentage is useful to increase the rice yield
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