Establishment And Evaluation Of New Materials For Nucleus-Cytoplasmic Male Sterile Lines And Restorer Lines In Gossypium Hirsutum

Breeding high-yield and high-quality hybrids is an important demand for cotton production.Creating sterile lines and restorer lines with good genetic background is of great significance for breeding strong heterosis hybrids.In this study,13 upland cotton lines with good comprehensive traits,13 lines with excellent fiber quality and 2 backbone parents were used as recipient parents.Material 851A with sterile gene and material ZB79185R with restorer gene were used as donor parents respectively to create new materials for sterile line and restorer line.The main results are as follows:1.By backcross breeding,male sterile line 851A was used as donor parent（female parent）,13 lines with good comprehensive traits,13 lines with excellent fiber quality and 2backbone parents were recipient parents（male parent）.F₁ was obtained by crossing the two lines and backcross for 5 generations.The plants with the worst fertility were selected for backcross in each generation.The pollen organs of the new sterile line materials were investigated.The results showed that the new sterile line materials had short filaments and exserted stigmas,no or fewer pollen grains,no pollen or a small amount of pollen,and thin pollen.The pollen viability was tested in combination with Fertility Survey in the late generations of backcross.Finally,15 new sterile lines with 100%sterile plant rate and complete pollen abortion were obtained.2.The donor parent ZB79185R of cytoplasmic male sterility（CMS）was used as female parent,and the above comprehensive lines,quality lines and backbone parents were used as receivers.Through hybridization,continuous backcrossing and assisted by advanced generation molecular markers,1752 individual plants of BC6F1 generation of 15restorer lines were identified by using SSR markers NAU6466 and COT10 closely linked with restorer genes,and 415 positive plants were screened.Fifteen new restorer lines were obtained from the seed inbred generation of sexual plants.The pollen organs of the New Restorer line materials were investigated.The results showed that the New Restorer line materials had long filaments,plump anthers,more pollen grains and large amount of pollen.The pollen activity of the restorer line was tested with 1%I₂-KI dye.The results showed that the restorer line had strong pollen activity and the plant was completely fertile.3.The results of investigation on Agronomic Traits of new materials of sterile lines showed that the plant height of sterile lines varied from 90.3 cm to 119.3 cm,the number of first fruit branches varied from 4.8 to 7.9 and the number of fruit branches varied from10.7 to 14.6.New materials with good agronomic traits such as QZH-2,QZH-4,QZH-7,QZH-10,QZH-12,QZH-16,QZH-18,QZH-19 and QZH-26 were screened out.4.Investigation results of Agronomic and quality traits of New Restorer materials showed that the plant height of restorer lines varied from 62.0 cm to 122.1 cm,the number of first fruit branches varied from 2.4 to 7.5,the number of fruit branches varied from 9.8to 15.0,the number of bolls varied from 4.0 to 30.0,and the number of rotten bolls varied from 0.0 to 0.8;18 materials with fiber length from 28 mm to 31 mm accounted for 45%of new materials,and those with strength above 30 cN/tex accounted for 35%of new materials and horses.Material with clone value above B level accounted for 70%of the new materials.Six New Restorer materials with good comprehensive properties,such as QZH-32,QZH-36,QZH-44,QZH-46,QZH-49 and QZH-80,were screened out.In conclusion,nine new sterile line materials with good genetic background were created in this study.The sterile plant rate of new sterile line materials was 100%,and pollen abortion was complete.Thirteen New Restorer Lines with good genetic background and 17 New Restorer Lines with good fiber quality were developed.The new materials have good fertility and strong pollen vigor.QZH-2,QZH-4,QZH-7,QZH-10,QZH-12,QZH-16,QZH-18,QZH-19 and QZH-26 were selected as new materials with excellent agronomic traits.QZH-32,QZH-36,QZH-44,QZH-46,QZH-49 and QZH-80 were selected as New Restorer Lines with good agronomic and quality traits.