Meeting the demand for high-quality japonica rice is a major challenge facing China's grain security. In the present study, a two-year field experiment was conducted to investigate the yield, quality, and profitab...Meeting the demand for high-quality japonica rice is a major challenge facing China's grain security. In the present study, a two-year field experiment was conducted to investigate the yield, quality, and profitability of japonica rice varieties(including hybrids and inbreds) grown in the late season as compared with local elite indica hybrids in a double rice cropping system of China where indicas are traditionally planted. Indica hybrids had significantly longer vegetative(from sowing to heading) and total(from sowing to maturity) growth durations than japonicas in both2011 and 2012, while reproductive growth duration(from heading to maturity) was longer for indica hybrids than for japonicas in 2011 but not in 2012. Indica hybrids produced higher grain yield than japonicas in 2011, but with no significant differences in 2012. Japonicas had higher brown rice, milled rice, and head rice percentages than indicas, but had lower gelatinization temperature and amylose content,while with no significant differences in gel consistency and protein content. Indica hybrids tended to have lower chalky grain percentage and chalkiness degree than japonicas, though the differences were not statistically significant due to large genotypic variations. The net returns were 16.1% and 9.9% greater for indica hybrids than for japonica hybrids and japonica inbreds in 2011, with only 3.8% and 1.3% in2012, respectively. Thus, our results suggest that replacing indicas with japonica varieties as late rice may not be feasible at the present site unless locally adapted japonica varieties are developed.展开更多
Conventional rice breeding has long focused on exploiting the DNA sequence diversity.However,epigenetic diversity,reflected particularly in DNA methylation,can also contribute to phenotypic variation and should not be...Conventional rice breeding has long focused on exploiting the DNA sequence diversity.However,epigenetic diversity,reflected particularly in DNA methylation,can also contribute to phenotypic variation and should not be overlooked in rice breeding.In this study,20 parental lines of indica rice,which are widely used in hybrid rice breeding in China,were analyzed to investigate variations of DNA methylation and its inheritance.The results revealed a wide diversity in DNA methylation among these breeding lines.A positive correlation was seen between DNA methylation and genetic diversity.Furthermore,some of the methylated DNA was inherited in the subsequent generation,regardless of whether they were produced by selfing or hybrid-crossing.This study provides insight into the methylation patterns in rice,and suggests the importance of epigenetic diversity in rice breeding.展开更多
基金Supported by grants from the China National Rice Research Institute and Jiangxi Province(GJJ12215 and 555 Talents Program)
文摘Meeting the demand for high-quality japonica rice is a major challenge facing China's grain security. In the present study, a two-year field experiment was conducted to investigate the yield, quality, and profitability of japonica rice varieties(including hybrids and inbreds) grown in the late season as compared with local elite indica hybrids in a double rice cropping system of China where indicas are traditionally planted. Indica hybrids had significantly longer vegetative(from sowing to heading) and total(from sowing to maturity) growth durations than japonicas in both2011 and 2012, while reproductive growth duration(from heading to maturity) was longer for indica hybrids than for japonicas in 2011 but not in 2012. Indica hybrids produced higher grain yield than japonicas in 2011, but with no significant differences in 2012. Japonicas had higher brown rice, milled rice, and head rice percentages than indicas, but had lower gelatinization temperature and amylose content,while with no significant differences in gel consistency and protein content. Indica hybrids tended to have lower chalky grain percentage and chalkiness degree than japonicas, though the differences were not statistically significant due to large genotypic variations. The net returns were 16.1% and 9.9% greater for indica hybrids than for japonica hybrids and japonica inbreds in 2011, with only 3.8% and 1.3% in2012, respectively. Thus, our results suggest that replacing indicas with japonica varieties as late rice may not be feasible at the present site unless locally adapted japonica varieties are developed.
基金supported by the National Natural Science Foundation of China(31071379)the Post-Doctoral Foundation of China(20090450616)a grant from"Yellow Crane"Special Talent Program of Wuhan
文摘Conventional rice breeding has long focused on exploiting the DNA sequence diversity.However,epigenetic diversity,reflected particularly in DNA methylation,can also contribute to phenotypic variation and should not be overlooked in rice breeding.In this study,20 parental lines of indica rice,which are widely used in hybrid rice breeding in China,were analyzed to investigate variations of DNA methylation and its inheritance.The results revealed a wide diversity in DNA methylation among these breeding lines.A positive correlation was seen between DNA methylation and genetic diversity.Furthermore,some of the methylated DNA was inherited in the subsequent generation,regardless of whether they were produced by selfing or hybrid-crossing.This study provides insight into the methylation patterns in rice,and suggests the importance of epigenetic diversity in rice breeding.
