Identification Of Distant Hybrids Between Maize And Teosinte And Selection Of High Quality Forage Germplasm

In order to breed new forage varieties with strong stress resistance,high yield and high quality,and solve the contradiction between the increasing demand for forage in China and the grassland ecological environment.In this study,the F₅generation mt-5（Maize Teosinte）plants obtained from the distant hybridization between the tassel free plant in F₂of the hybrid offspring of maize light and temperature sensitive tassel free line I478 and inbred line Mo17 and after multiple generations of selfing selection were used as the basic research materials.The basic characteristics and feeding quality were analyzed.The results are as follows:1.MT was identified and analyzed by DNA bar code technology.It was found that the sequence similarity between MT and Teosinte was 99.92%.Through blast analysis of NCBI database,it is found that it is consistent with MF143781.1 and HQ600085.1The sorghum sequence of grade 1 has 99.67%similarity.Finally,through phylogenetic tree analysis,it was found that MT and Teosinte clustered into one branch.2.The F₂analysis of the offspring of MT-5 and maize inbred line 116-2 showed that the agronomic and yield characters of the two lines had large coefficients of variation.In line 1,there was light and temperature sensitivity without tassel,while in line 2,there was small branch.3.Strain selection and feed quality test in 2020 showed that the three strains had strong tillering ability and regeneration ability.Through the performance of agronomic,yield and feed quality traits of the three lines,combined with feed quality evaluation methods such as emergy,RFV and chemical nutrient type classification,MT-6-1 with better comprehensive traits was selected for line selection.4.The strain selection test in 2021 found that in terms of agronomic characters,the plant height and stem diameter in 2021 were significantly greater than those in 2020;In terms of biomass,the fresh weight and dry weight of the whole plant in 2021 are significantly higher than those in 2020;In terms of basic feed nutrition,the contents of nitrogen-free extract,neutral detergent fiber,crude fiber and phosphorus in 2021 were significantly higher than those in 2020,the content of crude protein in 2021 was lower than that in 2020,and the RFV of all five strains was greater than 100 in 2021.However,in the division of nutritional types,it was found that the five strains were CN type in 2021,and the quality was lower than that of the three strains in 2020;It is found that the digestible value and the total value of nutrients in 2021 are significantly higher than those in 2021.The results showed that the selection of strains in 2020 was relatively successful.Five strains were screened and found that MT-6-1-1、2 had good performance（MT-6-1-3、4 were sensitive to low temperature）.It should continue to add generations and select strains.5.The experiment of suitable harvest time showed that the number of leaves,plant height,stem diameter and tiller number of main stem were consistent with logistic regression.On the 80th day after planting,the plant is at the turning point from booting stage to heading stage,which is the time when the plant changes from vegetative growth to reproductive growth.At this time node,larger yield and better quality can be obtained.6.The density screening test showed that when the planting density was 75000 plants/hm²,it had the maximum fresh and dry grass yield and the highest yield of basic nutrients.At the same time,RFV was greater than 100,and all emergy and TDN had good performance except net energy of weight gain.Therefore,under the condition of plant density,it has the characteristics of high biological yield,high yield of forage nutrients,excellent forage value and high emergy value.In this paper,the new material mt-5 was tested in two aspects.On the one hand,the material was identified by DNA Barcode technology,and it was preliminarily used to hybridize with maize inbred lines and observe the character separation.On the other hand,the feed utilization value and potential of the new material were deeply explored from the aspects of agronomic characters,biological yield,feed nutritional value and so on.It was concluded that the material has feed potential and strain selection was carried out.At the same time,the suitable harvest time and density of the material were further screened,so as to lay a theoretical foundation for the later cultivation experiment of high yield and high quality.It provides an important reference basis for making full use of abundant wild germplasm resources of maize and cultivating high-yield and high-quality forage maize.