| Oats(Avena sativa L.),as one of the mainorage crops,which has high quality and play an important role in the production of animal husbandry in China.With the vigorous development of animal husbandry in the south of China,insufficient supply of forage seeds and backward seed production technology have become one of the main reasons for restricting forage production in the south of China.For gramineous plants,spike length,spikelet number,floret number,and lemma and lemma traits of floret have direct effects on the grain growth and yield.In order to clarify the effects of inflorescence structural characteristics and grain characteristics on grain yield,and find ways to improve grain yield.In this study,a total of 141 oats'varieties(lines)were collected,and 14 major agronomic traits were analyzed for genetic diversity.Using grain characteristics as screening targets,a total of 22 specific germplasms were screened as test materials,including 15 hulled oats and 7 naked oats.Hulled oats and naked oats on the grain characteristics is analyzed by measuring and comparing the inflorescence characteristics and grain characteristics,the effect of the inflorescence structure;Correlation and path analysis are performed to analyze the oat seed yield by determining the seed yield-related traits of oat germplasm and its seed yield.According to the constituent factors and trait characteristics.Oats are self-pollinating plants with homozygous genotypes in the species,which means cross-breeding has high advantages.In this study,grain yield was used as the screening target.Finally,the F2 population of the hulled oat "Huaiyan 9" ืthe naked oat "Huaixuan 6"was used as materials for selecting excellent lines of oats by crossed.The F1 and F2 groups were investigated in 2017 and 2018,four inflorescence structural characteristics(ear length,spikelet number,round layer number,small flower number)and three grain characteristics(grain length,grain width,grain height)were studied through the main gene+polygenes mixed genetic model method for analyzing the genetic variance and gene effects of 7 traits related to seed yield and showed the genetic mechanism of seed yield-related traits which provided a theoretical basis for formulating corresponding breeding strategies and provide guidance for the selection and breeding of oat lines with high and stable yield in Jianghuai region.The main findings are as follows:1.This study analyzed the genetic diversity of 16 agronomic traits of 141 oat germplasms and indicated that the range of tested oat traits varied from 17.1%to 41.79%,with a large variation and rich genetic diversity.In particular,the genetic diversity indexes of the three traits of fresh weight per plant,thousand-grain weight and dry weight per plant are very high,which are 2.64,2.33,and 2.48,respectively.2.There were significant differences of the characteristics of grains and grains between hulled oats and naked oats.The hull ratio of hulled oats varies from 51.1%to 20.8%,and the average hull ratio was about 35.1%.The peeled oat and naked oat were relatively found that the oat was generally oval in shape and full in grain.Naked oat grains were mostly long barrels.Thousand grains of naked oats were heavier.There was a significant positive correlation between grain length and grain width(P<0.01).The ratio of grain length and grain width was fixed between the same kind of grains,and the ratio of grain length to grain width varies greatly between different germplasms.Own genotype was one of the main factors that affected the granulocyte type3.There were significant differences in the inflorescence structure of hulled oats and naked oats,and the difference in the number of florets was significant(P<0.01);both the florets are negatively correlated with the seed 1000-grain weight,and there is a mutual restriction between the number of florets and the 1000-grain weight.The comparison of the lemma characteristics of hulled and naked oats revealed that there were significant differences in the width between hulled oats and naked oats,width of lemma and width of lemma(P<0.05).The more spacious floret structure helps the growth and development of larger grains.4.Correlation analysis of the inflorescence structure and grain characteristics of naked oats revealed that the number of florets and spikelet's had a negative correlation.The greater the number of florets,the fewer the number of spikelet,the number of florets and spikelet's existed.Mutually constrained relationship.The spike length was very significantly positively correlated with the grain length of naked oats(P<0.01)5.There was a significant difference in seed yield and yield component factors between hulled oats and naked oats.,is the results found that plant height was negatively correlated with seed yield,effective tiller number and seed yield through correlation analysis on seed yield traits of hulled oats germplasm which was a positive correlation is the results found that plant height and stem thickness had a limiting effect on the effective number of tillers of hulled oats.Appropriately reducing plant height and stem thickness could significantly increase the number of tillers6.According to the correlation analysis of the relative yield of seed yield of naked oat germplasm,the number of florets is negatively correlated with the yield of naked oat seeds(P<0.05),and the correlation coefficient was the highest;In the growth of naked oat seed production,select small flowers for the selection and breeding of moderate number of germplasm,which should be sown early in a timely manner,extended the growth period and gave sufficient fertilizer to ensure the quality of the seeds and maximize their seed yield.7.Through the hybridization of hulled and naked oats,the inflorescence structure and grain characteristics are dominant traits in the form of naked oat grains.The results found that the F1 generation grains are almost all except the grains with husks formed by underdeveloped complete florets through comparison of grain characteristics.It is a bare grain type,and compared with the parent "Huaixuan 6" grain,the grain was fluffier and the grain color was darker.The inflorescence structural characteristics and grain characteristics of F2 generation were separated,and the ratio of plant type with male parent panicle type to female parent with panicle type was about 1:3.The grains showed that the ratio of hulled oats to naked oats was also about 1:3.8.According to the minimum rule of AIC value,select the candidate model,used the uniformity test for suitability test,and selected the best model.The results showed that the four inflorescence structural characteristics and the three grain structural characteristics of the F2 generation of hulled and naked oat hybrids were controlled by two pairs of main genes and multiple micro-effect genes.The second-order parameter analysis of spike length and spikelet number showed that the environmental shadow variance was significantly larger than the performance variance,the results indicated that it was greatly affected by environmental factors.The main gene heritability of grain length(94.2)is the highest.That the additive effect can be used for breeding for the selection of grain length. |
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