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Heterosis and Combining Ability for Callus Growth Rate in Rice
Author(s) -
Kuroda Shigeru,
Kato Hiroshi,
Ikeda Ryoichi
Publication year - 1998
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1998.0011183x003800040008x
Subject(s) - heterosis , diallel cross , biology , callus , japonica , hybrid , oryza sativa , botany , subspecies , cultivar , relative growth rate , horticulture , growth rate , genetics , gene , geometry , mathematics , paleontology
To explain heterosis in rice ( Oryza sativa L.) at the cellular level, we studied the inheritance of callus growth rate in seed‐derived calli from a 14‐by‐14 diallel cross that used four japonica , four javanica (the tropical type of japonica ), and six indica cultivars. Callus growth rates were calculated from gains in fresh callus weight that were measured after 28 d of culture at 20, 28, 35, and 40°C in the dark. All F 1 crosses between subspecies had significantly ( P < 0.05) higher callus growth rates than the parental lines. The F 1 crosses showed greater tolerance for low temperature than their parents. Analysis of variance of diallel crosses showed that additive and dominance effects on the callus growth rate were both significant ( P < 0.01). Variances for general (GCA) and specific combining ability (SCA) callus growth rate were also highly significant. Among crosses between subspecies, japonica × indica showed the most positive SCA effects for callus growth rate at 28 and 35°C, while japonica × japonica and indica × indica showed negative SCA effects at 20 to 35°C. The magnitude of the SCA effects on hybrids at 28°C correlated significantly with that of plant growth in the field from a previous study ( r = 0.867, 0.01 < P < 0.05, df = 4). Midparent heterosis for the callus growth rate was clearly positive and significant and was greatest in japonica × indica crosses in the combination groups at 28°C. Heterosis and SCA effects for this trait at 28°C were related to the genetic distance between parental subspecific groups.