TY - JOUR
T1 - Yield response of indica and tropical japonica genotypes to soil fertility conditions under rainfed uplands in northern Laos
AU - Asai, Hidetoshi
AU - Saito, Kazuki
AU - Samson, Benjamin
AU - Songyikhangsuthor, Khamdok
AU - Homma, Koki
AU - Shiraiwa, Tatsuhiko
AU - Kiyono, Yoshiyuki
AU - Inoue, Yoshio
AU - Horie, Takeshi
N1 - Funding Information:
This study was conducted with financial support from S-2 (3) b. Program by the Global Environment Research Fund, Ministry of Environment of Japan. The authors thank Mr. Banthasack Vongphouthone for his field assistance, Ms. Chiaki Muto and Mr. Kohtaro Iseki for their support of DNA analysis and Drs. Keisuke Katsura and Yoichiro Kato for their helpful suggestions. The authors also express their appreciation to Dr. Gary Jahn, former representative of IRRI-Greater Mekong Sub-Region Office for his affording every facility for our research.
PY - 2009/6/26
Y1 - 2009/6/26
N2 - Traditional tropical japonica genotypes (Oryza sativa) are typically grown without fertilizer for subsistence in slash-and-burn systems by resource-poor farmers in northern Laos. Recent short fallows have reduced soil fertility and rice productivity in these systems. Genotypes adapted to a range of soil fertility conditions are needed for their food security. Rainfed experiments were conducted to identify genotypes with high yield and to examine the nature of genotype by environment (G × E) interaction for grain yield. Two improved indica genotypes and seven traditional genotypes including indica and tropical japonica groups were grown without fertilizer in ten environments over the course of 2 years. The effects of G, E and G × E interaction were significant for grain yield, yield components, plant height and days to flowering. Two improved indica genotypes (B6144F-MR-6-0-0 and IR 55423-01) and a traditional indica genotype Chao Mat out-yielded the other genotypes across the environments (2.1 t ha-1 vs. 1.6 t ha-1). Pattern analysis showed that 40.2% of the G × E sum of squares was captured by a two genotype group by two environment group summary. One environment group had higher contents of soil organic carbon and extractable P and K, and mean grain yield than another environment group. The performance of one genotype group including consisting of improved and traditional indica genotypes was more stable across two environment groups than that of another group consisting of tropical japonica genotypes, which performed well only in the high soil fertility environment group. The low grain yield of tropical japonica genotypes in the low soil fertility environment group was the result of low sink size and grain-filling percentage. In conclusion, two improved genotypes are identified for high yield in both low and high soil fertility conditions and soil organic carbon appears to be a major factor contributing the G × E interaction for grain yield as well as overall productivity.
AB - Traditional tropical japonica genotypes (Oryza sativa) are typically grown without fertilizer for subsistence in slash-and-burn systems by resource-poor farmers in northern Laos. Recent short fallows have reduced soil fertility and rice productivity in these systems. Genotypes adapted to a range of soil fertility conditions are needed for their food security. Rainfed experiments were conducted to identify genotypes with high yield and to examine the nature of genotype by environment (G × E) interaction for grain yield. Two improved indica genotypes and seven traditional genotypes including indica and tropical japonica groups were grown without fertilizer in ten environments over the course of 2 years. The effects of G, E and G × E interaction were significant for grain yield, yield components, plant height and days to flowering. Two improved indica genotypes (B6144F-MR-6-0-0 and IR 55423-01) and a traditional indica genotype Chao Mat out-yielded the other genotypes across the environments (2.1 t ha-1 vs. 1.6 t ha-1). Pattern analysis showed that 40.2% of the G × E sum of squares was captured by a two genotype group by two environment group summary. One environment group had higher contents of soil organic carbon and extractable P and K, and mean grain yield than another environment group. The performance of one genotype group including consisting of improved and traditional indica genotypes was more stable across two environment groups than that of another group consisting of tropical japonica genotypes, which performed well only in the high soil fertility environment group. The low grain yield of tropical japonica genotypes in the low soil fertility environment group was the result of low sink size and grain-filling percentage. In conclusion, two improved genotypes are identified for high yield in both low and high soil fertility conditions and soil organic carbon appears to be a major factor contributing the G × E interaction for grain yield as well as overall productivity.
KW - Cropping intensity
KW - Genotype by environment interaction
KW - Indica
KW - Low soil fertility
KW - Northern Laos
KW - Slash-and-burn
KW - Soil organic carbon
KW - Tropical japonica
KW - Upland rice
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U2 - 10.1016/j.fcr.2009.02.010
DO - 10.1016/j.fcr.2009.02.010
M3 - Article
AN - SCOPUS:67349191032
SN - 0378-4290
VL - 112
SP - 141
EP - 148
JO - Field Crops Research
JF - Field Crops Research
IS - 2-3
ER -
