The Fragrance Improvement Of Restorer Line Xinhui 1998

Rice is the largest grain ration crop in China.With the improvement of people’s living standards,people are paying more and more attention to the quality of rice.Fragrant rice is favored by Chinese consumers and has a huge market demand potential.Currently,there are not many high-yield and quality aromatic rice varieties in China,so cultivating high-yield and quality aromatic rice varieties is of great significance for improving the economic benefits of grain cultivation and promoting the development of the rice industry.This experiment used Changxiang 15,which carries homozygous aroma alleles and has excellent rice quality,as the donor parent,and the high-yield restoring line Xinhui 1998（hereinafter referred to as R1998）as the recipient parent.Through hybridization,backcrossing,and molecular marker-assisted selection methods,excellent individuals with homozygous aroma alleles,high yield per plant,and good rice quality were selected.The main results are as follows:1.Using the hybridization between donor parent Changxiang 15 and recipient parent R1998,16 single plants with homozygous aroma alleles,numbered XD1-16,were screened in the BC₂F₂population through two backcrosses and self crosses combined with molecular marker assisted selection.2.The main agronomic traits of 16 improved individual plants were investigated,and the results showed that all improved individual plants had the same aroma as the donor parents;The heading date of the improved individual plant was earlier than that of the recurrent parent R1998.The earliest heading date was XD16,15 days earlier than R1998,and the latest was XD1,1 day earlier than R1998;The plant height of the improved single plant is higher than or equal to the plant height of the recurrent parent,and the plant height of XD13 is consistent with R1998;The length and width of the flag leaves of most improved individual plants are between the two parents,among which 4individual plants were similar to the recurrent parent and 4 individual plants were similar to the donor parent;The tillering number of improved individual plants varied greatly,with 5 individual plants being similar to their recurrent parents;The panicle length of 8 individual plants was longer than that of their recurrent parents;The yield per plant of XD1 and XD13 was higher than that of their recurrent parents.3.Analyze the processing and appearance quality traits of 16 individual plants,and the results indicate that the head rice rate of XD14 was higher than that of the recurrent parent,and XD1 was comparable to that of the recurrent parent,while the other improved individual plants were lower than R1998;The chalkiness grain rate and chalkiness degree of XD13 were lower than those of its recurrent parent but higher than those of Changxiang 15;The chalkiness seed setting rate and chalkiness degree of XD1was closest to the recurrent parent;The grain type length-width ratio of the improved individual plant was greater than or equal to R1998.4.The coefficient of variation and significant difference analysis was conducted on homozygous and heterozygous individuals with aroma alleles,and the results showed that homozygous and heterozygous individuals were superior to their recurrent parent R1998 in terms of 1000-grain weight and grain type length-to-width ratio,but higher than R1998 in terms of plant height,chalky grain rate,and chalkiness,with a relatively large coefficient of variation.In homozygous single plants,there are significant level differences between plant height and some traits,so subsequent breeding needs to be conducted in the direction of low chalkiness and dwarf.On the other hand,the mean values of tillering,panicle length,filled grains,and seed setting rate of homozygous individuals were significantly lower than those of recurrent parent R1998,while the mean values of heterozygous individuals were higher than those of R1998.Moreover,there is a significant level of difference between the number of filled and empty seeds and other traits,so more attention should be paid to the screening of yield-related traits in the breeding process of homozygous single plants.5.By constructing a cluster diagram of agronomic traits between improved individual plants and their parents,it was found that the similarity between six individual plants such as XD1 and XD13,and their recurrent parent R1998 was over90%.Using 244 SSR primers evenly distributed on rice chromosomes,genetic background analysis of recurrent parents and improved individual plants showed that the average background recovery rate of the improved lines was 90.06%,with the highest background recovery rate of XD1 being 94.88%and the lowest XD10 being86.48%.6.Hybridize the recipient parent R1998 with the sterile line Chang1S,and hybridize the improved single plant with homozygous aroma genes with the sterile line Chang1S.The analysis of the agronomic traits of hybrid combination F1 showed that the improved single plant combination was earlier in the heading stage than the recipient parent combination,but there was no significant difference in tillering,plant height,grain number,and yield per plant compared to the recipient parent combination.After conducting aroma analysis on hybrid combinations,it was found that the combination matched by the recipient parent did not have any aroma,while the combination matched by the improved individual plant had weak aroma,indicating that the selected improved individual plant has potential application value and laid a good material foundation for cultivating excellent varieties with aroma in the future.