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United States Department of Agriculture

Agricultural Research Service

Title: Production and heterosis analysis of rice (Oryza sativa L.) autotetraploid hybrids

Authors
item Tu, Shengbin, - CHINESE ACADEMY OF SCI
item Luan, Li - CHINESE ACADEMY OF SCI
item Liu, Yuhua - CHINESE ACADEMY OF SCI
item Long, Wenbo - CHINESE ACADEMY OF SCI
item Kong, Fanlun - CHINESE ACADEMY OF SCI
item He, Tao - CHINESE ACADEMY OF SCI
item Xu, Qiongfang - CHINESE ACADEMY OF SCI
item Yan, Wengui
item Yu, Maoqun - CHINESE ACADEMY OF SCI

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 20, 2007
Publication Date: October 30, 2007
Citation: Tu, Shengbin, Luan, L., Liu, Y., Long, W., Kong, F., He, T., Xu, Q., Yan, W., Yu, M. 2007. Production and heterosis analysis of rice (Oryza sativa L.) autotetraploid hybrids. Crop Science. 47:2356-2363.

Interpretive Summary: Poor fertility is the main barrier for utilizing heterosis between the two rice (Oryza stiva L.) sub-species, indica and japonica, in hybrid rice production by the cytoplasmic male sterile (CMS) system. Recently, the development of autotetraploid hybrids (2n=4x=48) from autotetraploid parents has been suggested as a new method for increasing heterosis in hybrid rice. Using standard experimental protocols, the elite diploid rice male sterile, maintainer, and restorer lines were colchicine-treated and autotetraploid counterparts of the diploid lines were obtained. The autotetraploid lines were used to produce seven autotetraploid hybrids which were analyzed for heterobeltiosis (HB), where the F1 plants were compared to their male parent or restorer plants, and the degree of heterosis, where the F1 plants were compared to the diploid commercial hybrid cultivar, Shanyou 63. The HB among the autotetraploid hybrids ranged from 1.4 to 105.9% for the productive panicles per plant, 0.5 to 74.3% for total kernels per panicle, 17.6 to 255.7% for filled kernels per panicle, and 9.6 to 130.4% for seed set. Improvements in these yield components resulted in the HB for kernel yield ranging from 64.8 to 672.7% among the seven hybrids. Hybrids T461A/T4002 and T461A/T4193 yielded 46.3 and 38.3% more, respectively than Shanyou 63, and all other hybrids but one yielded the same or more than Shanyou 63. The high heterosis for yield resulting from improved kernel fertility suggests that hybrid sterility between indica and japonica rice may be overcome by using tetraploid lines followed by intensive selection. Also, the gigantic features of the autotetraploid hybrids may establish a plant structure better able to support the higher yield.

Technical Abstract: It is hard to achieve good seed set in hybrid rice between cultivarsof the same Oyrza sataiva L sub-species, and even harder in hybrids between the two rice sub-species, indica and japonica. The wider cross has greater hybrid vigor or heterosis. Cytoplasmic male sterile (CMS) system used widely and successfully in China and Asia consists of three parents, male sterile lines, maintainer and restorer. Rice is diploid with two sets of chromosomes (2n=2x=24, AA) and becomes autotetraploid (2n=4x=48, AAAA) when its chromosomes are doubled by the chemical, colchicine. Recently, the development of autotetraploid hybrids from autotetraploid parents has been suggested as a new method for increasing heterosis in hybrid rice. Using standard experimental protocols, seven autotetraploid hybrids were produced and analyzed for heterobeltiosis (HB), where the F1 plants were compared to their male parent or restorer plants, and practical heterosis, where the F1 plants were compared to the diploid commercial hybrid cultivar, Shanyou 63. The HB among the autotetraploid hybrids ranged from 1.4 to 105.9% for the productive panicles per plant, 0.5 to 74.3% for total kernels per panicle, 17.6 to 255.7% for filled kernels per panicle, and 9.6 to 130.4% for seed set. Improvements in these yield components resulted in the HB for kernel yield ranging from 64.8 to 672.7% among the seven hybrids. Hybrids T461A/T4002 and T461A/T4193 yielded 46.3 and 38.3% more, respectively than Shanyou 63, and all other hybrids but one yielded the same or more than Shanyou 63. The high heterosis for yield resulting from improved kernel fertility suggests that hybrid sterility or poor seed set between indica and japonica rice may be overcome by using autotetraploid lines followed by intensive selection. Also, the gigantic features of the autotetraploid hybrids may establish a plant structure able to support the high yielding hybrid rice plants.

Last Modified: 9/10/2014
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