Sindongjinbyeo is a new japonica rice cultivar developed from a cross between Hwayeongbyeo and YR13604Acp22 line by the rice breeding team of National Honam Agricultural Experiment Station (NHAES), RDA, in 1999. This cultivar has a large grain and about 1

Mihyangbyeo, a new japonica aromatic rice (Oryza sativa L.) was developed by National Honam Agricultural Experiment Station (NHAES), RDA in 1998. It was derived from the three-way cross among Seomjinbyeo of the disease resistance and high yielding lines,

Inweolbyeo is a japonica rice (Oryza sativa L.) variety developed by Unbong Substation, National Honam Agricultural Experiment Station, RDA in 1998. It was selected from progenies from a cross between Fukei 127 and Unbongbyeo by pedigree breeding method.

“Hoanbyeo” is a new japonica rice cultivar developed from a cross between Kanto149 and Milyang95 by the rice breeding team of National Honam Agricultural Experiment Station (NHAES), RDA, during 1990 to 1998. This cultivar requires about 121days of growth

“Sobibyeo” is a new japonica rice cultivar developed from a cross betw een Hwayeongbyeo and YR13604Acp22 line by the rice breeding team of National Honam Agricultural Experiment Station (NHAES), RDA, in 1999. This cultivar has a large grain and about 119

Four different rice varieties, Sindongjinbyeo, Dongjin #1, Saegyehwabyeo, and Iksan 467, were transplanted under three different nitrogen levels and two different seedling numbers per hill to obtain basic information on panicle traits under different cultural conditions and to propose the ideal panicle structure in Japonica rice. Sindongjinbyeo and Iksan 467 were characterized by more primary rachis branches (PRBs) per panicle and more grains on PRB than other cultivars. The two varieties also had fewer secondary rachis branches (SRBs) per PRB and fewer grains on SRB per PRB. These characteristics, consequently, resulted in higher ripened grain rate, contrary to that of Dongjin #1 and Saegyehwabyeo. In the correlation coefficient analysis, PRB number per panicle and grain number on PRB per panicle were positively correlated with ripened grain rate, while SRB number per panicle, number of grains on SRB per panicle, SRB number per PRB, number of grains on SRB per PRB and grain number per panicle were negatively correlated with ripened grain rate. Therefore, the number of grains on PRB per panicle, SRB number per PRB and the number of grains on SRB per PRB were the appropriate criteria for determining and achieving higher ripened grain rate in rice. High ripened grain rate over 90% was obtainable with over 12.5 PRBs per panicle and 63 grains on PRB per panicle, and with under 1.7 SRBs per PRB, 5 grains on SRB per PRB, 130 grains per panicle, and 14 panicles per hill. The study recommended that for over 90% high ripened grain rate, the critical limiting factors should be under 2 SRBs per PRB, 6 grains per PRB, and 130 grains per panicle, irrespective of the PRB number per panicle and the number of grains on PRB.

In order to obtain the genetic information on rachis traits of rice panicle, half diallel analysis for primary and secondary rachis branches was conducted using six crosses of F₁s from four parents. Both additive and dominant gene effects were

To investigate the effects of planting density and nitrogen level on growth and yield potential of newly bred heavy panicle japonica rice with large grain (Iksan 435 and Iksan 438) or many spikelets per panicle(HR14022-21-8-4 and HR14022-21-8-6), four heavy panicle type rices and two many panicle type rices(Dongjinbyeo and Donganbyeo) as the checks were planted under standard planting density (30~times 15 cm) and dense planting density (15~times 15 cm) with two nitrogen levels of standard nitrogen level(110 kg h a-1 ) and heavy nitrogen level(165 kg h a-1 ). Effective tiller rate decreased in dense planting or heavy nitrogen, when compared to standard nitrogen and planting, while leaf area index and to dry weight increased in dense planting or heavy nitrogen. Tiller numbers and panicle numbers were more increased by dense planting than heavy nitrogen, whereas spikelet numbers were more increased by heavy nitrogen than dense planting. Ripened grain ratio was slightly lower only in dense planting. 1,000 grain weight in brown rice was not significantly different in dense planting or heavy nitrogen. Milled rice yield was highest in heavy nitrogen with standard planting for heavy panicle type rice, while yield for many panicle type rice was highest in heavy nitrogen with dense planting, suggesting that many panicle type rice possesses higher adapt-ability for dense planting than heavy panicle type rice. Path coefficient analysis revealed that top dry weight, spikelet number and grain weight were the greatest positive contributors to yield, whereas tiller number was negative to yield.d.