Application Evaluation And Analysis Of New Conventional Rice Varieties In Guangdong

In recent years,Guangdong Province has made remarkable achievements in the selection and breeding of high quality conventional rice.It has successively bred and approved a large number of new varieties with high quality and high yield.Due to the diversity of rice varieties and the complexity of their performance,it is a real challenge to evaluate the rice varieties scientifically,reasonably and accurately.It is of great significance to select elite varieties and apply them in time.In this study,a comprehensive analysis of the yield,quality and resistance of the tested conventional varieties was conducted using regional experimental data collected from 2011 to 2015 in Guangdong.The conclusions of this paper are as follows:1.In the early crop seasons of 2011-2015,29.42% of the tested varieties surpassed the control variety in yield at significant level,and 24.17% of the tested varieties decreased significantly in yield than the control variety.However,in the late crop seasons,39% of the tested varieties increased significantly in yield than the control variety,with 19 % of the tested varieties decreased significantly.The results showed that the number of grains per panicle,seed setting rate,and 1000-grain weight of some of the tested varieties were higher than that of the control group.Therefore,the increase rate in yield reached a significant or extremely significant level.While,the seed setting rate and 1000-grain weight of some of the tested varieties were lower than the control group,which resulted in that the yield reduced than the control variety significantly or extremely significantly.The percentage of varieties with significant increase in production in the late crop seasons was higher than that in the early crop seasons,and the percentage of varieties with significant reduction in production in the late crop seasons was significantly lower than that in the early crop seasons.Both in the early and late crop seasons,some control varieties were unreasonably to be used.Selecting the appropriate regional test control varieties was conducive to promoting the healthy development of conventional rice breeding in our province.2.In the early crop seasons,the test varieties that reached the national or provincial standards accounted for 9.60% of the total varieties.Among the non-standard varieties,there were 72.57% varieties showing low percentage of polished rice and 74.34% varieties with substandard amylose content.The reason resulting in the substandard rice quality during the early crop seasons was mainly due to the low percentage of polished rice and non-standard amylose.Though,78.69% of the total varieties met the national or provincial standards in the late crop seasons,while 91.43% of the non-standard varieties were beyond the amylose content.The reason leading to the substandard rice quality in the varieties of late crop seasons was mainly due to the substandard amylose content.It is concluded that for the varieties in the early crop seasons,the percentage of polished rice and amylose content that did not meet the standard was higher than that in the late crop seasons.While the varieties that with lower amylose content than the national and provincial standards in the early crop seasons were more than that in the late crop seasons.This difference is due to the difference in tested varieties and the different climatic conditions in the early and late crop seasons.The results of quality analysis showed that the main indicators of unstandard rice in our province were amylose content and head rice rate.Therfore,amylose content and head rice rate were the focus for rice improvement in the future.3.By analyzing the blast resistance of the 149 varieties that had passed the certification in Guangdong Province during 2011-2015,the proportion of varieties above the resistance level reached 57%.It is indicated that in recent years the various breeding units in the province pays more and more attention to rice blast resistance and the use of blast resistance germplasm resources.By analysis of the resistance sources of rice blast,28-zhan and Qing-liu-ai 1 were identified as the main two rice blast resistant parents.The number of new conventional rice varieties which derived from the two parents was as high as 42 and accounted for 77.78% of the varieties resistant to rice blast.Through analysis of the resistance resources,it showed that it is very important to select appropriate resistance resources as parents for the development of new varieties resistant to rice blast.4.The results of high yield and stable yield in the early crop seasons from 2011 to 2015 showed that the varieties of Huangguangyouzhan,Nanfengzhan and Huangsifengzhan had high and stable yield.However,many varieties had high yield but unstable yield.According to the results of the late crop seasons,Huangguanghuazhan No.1,Huangruanxiuzhan,Xinyuanzhan and other varieties had high and stable production in yield.There also existed many varieties which showed high yield but unstable production.Whether the varieties form the early crop seasons or late crop seasons,only a few showed both high and stable yield,and most high-yield varieties do not show stable yield.It shows that these varieties showed different yield level at different test points,and the adaptability of these varieties needs to be improved.5.There were four new varieties approved during 2011-2015 in our province which have been planted in large scale.They were Huangguangyouzhan,Wushanfengzhan,Hefengsimiao and Yuehesimiao,respectively.The main reasons may be attributed to the high and stable yield of these varieties,the strong lodging resistance and cold resistance,and the better resistance to rice blast and bacterial blight.Besides,the daily production of each variety is relatively high,which are 3.63 Kg,3.35-3.45 Kg,3.31-3.66 Kg and 3.97-4.17 Kg,respectively.Among them,Yuehesimiao not only showed the good plant type but also high grain quality,which made it to be more suitable for market demand.Therefore,the planting area of Yuehesimiao is increasing faster than that of other varieties in Guangdong,and the planting area in 2017 has reached 22.4 million mu.