| Ratoon rice is a high efficient rice producting practice,which is an important way to solve the problem of labor scarity and to meet the food demand.In recent years,the rapid increase of ratoon rice acreage in central China.However,the specific varieties for ratoon rice have not been breeded,and the head rice yield in ratoon crop needs to be improved due to machine harvest in main crop.Therefore,the purposes of this research were to screening of high,stable yield and high quality varieties for ratoon rice,and to explore whether potassium fertilizer could improve the head rice yield in ratoon rice.Based on the purposes,field experiments were set in Jiupu village Chidong town of Qichun County,Huanggang city of Hubei province in 2015 and 2016.The suitability of grain yield among 15 different varieties for ratoon rice was tested.Experimental design was a randomized complete block with 3 replications.At the same time,the experiment studying effects of potassium fertilizer on the head rice yield in ratoon crop was conducted in 2015.The main results were as follows:(1)Yearly differences in main and ratoon crop was detected.Both yields of main and ratoon crop in 2015 higher than those in 2016 respectively.There were significant difference among different varieties in single year.High yielding varieties were SLY5814,LLYHZ and CLY4418 in 2015 main and ratoon crop,and those were YY4949 and LLYHZ in 2016.(2)The stability of grian yield was significantly different among varieties.Some of them were high yield both in main and ratoon crop of 2015 and 2016(such as LLYHZ and GLY476).Some were low yield both in main and ratoon crop of 2015 and 2016(such as HHZ and XLY223).Some were high yield in main crop but low in ratoon crop(such as TYHZ and WY308).Other varieties showed no consistent rules.(3)There were some characteristics and reasons of achieving high,stable grain yield or low grain yield among different varieties.LLYHZ and GLY476 showed high and stable yield is due to the total biomass and panicles per unit area were larger;HHZ showed low grain yield mainly due to its short growth period and the low total biomass both in main crop and ratoon crop,while XLY223 showed low grain yield mainly because of the number of spikelets per unit area and the grain setting rate were lower;TYHZ and WY308 performanced excellent in grain yield mainly due to their compensation effect of yield components were better in main crop,while showed low gain yield mainly due to their ratooning ability,growth period and biomass were lower in ratoon crop.(4)Significant differences were found in rice quality between the main crop and the ratoon crop.In most varieties,the head rice percent,amylose content and alkali spreading value of ratoon crop were higher than those in the main crop,and the chalky rice rate,chalkiness and gel consistency of the rice in the ratoon crop were lower than those in the main crop.In reference to the national standard of quality rice(GB/ T178912-1999),the head rice percent,chalky rice rate and chalkiness of most varieties in ratoon crop increased by 1-2 grades over than those in main crop.(5)There were significant differences in rice quality among different varieties.YY4949,SLY5814,LLYHZ,FLYX1,GLY476 and CLY4418 were higher total head rice yield and lower chalkiness.The gel consistency and amylose content of YY4949 and GLY476 is better among them.The head rice yield,chalkiness,gel consistency and amylose content of YY4949,LLYHZ,CLY4418 and FLYX1 were better in rice of ratoon crop.(6)The results showed that there were no significant effects of different potassium fertilizer applications on grain yield and head rice yield in ratoon crop.In a summary,LLYHZ and GLY476 show excellent grain yield,which can be popularized and applied in Hubei province and other areas.The grain yield and rice quality of the indica-japonica hybrid combination YY4949 were perfect,which was suitable for the application of japonica ratoon rice area. |
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