Studes On The New Ecological Male Sterile Line In Common Wheat Cultivars

At present, the ecological male sterile lines of crops, such as rice, sorghum, rape, barley, corn and wheat, were demonstrated around the world. The fertility of microspore is effecter by photoperiod and temperature. This new type male sterile lines have more merits than the cytoplasmic male sterility in crop heterosis utilizing. For example, the male sterility is easy to restore, the hybrid seed is convenient to produce, the cost of hybrid seed is low, the parents of crosses are easy to select. This male sterility system has been used to produce the two-lines hybrids on rice, and then the hybrid rice has preceded a new stage. On the wheat, a large number of photo-thermo sensitive male sterility have been cultivated in China, it opens up the two-lines producing hybrids on wheat. In this experiments, the materials named PTS were provided by the team of teaching and researching in wheat breeding of Agronomy Department in NWSTUAF. The materials were planted in different times at Yang Ling. Studies on Cytological observations on male sterile anther and pollen development, the selfed seed fertility (%) of F1 hybrids and segregation of the fertile and sterile plants in the F2 generation of 5 crosses, are carried out in 1999-2001. 30 crosses are used to study the fertility restoring of this male sterility and restored relation with two parents. The results show:1. The PTS lines are low temperature and short photoperiod sensitive. The lower temperature is a main factor of causing male sterility of it, and shorter photoperiod enforces the sterility degree. The fertility degeneration is more complex. It shows the reduction division is abnormal: in the middle stage â… of reduction division , there are the logging chromosomes; The chromosome bridge appears in the later stageâ… of reduction division; the halfer with little nucleus in the last stage â… and the quarter with little nucleus in the last stage â…¡. The development of pollen particle deforms: from the two-nucleus pollen particle to the three- nucleus one, the vegetative cells are dissolved, the generative cells devise normally to produce two male gametes of crescent moon. The mature pollen with two sperms is multi. The coloring of pollen with I2-KI dye liquor is light. The sterility of these lines is pollen-withered.2. The fertility of F1 generation is normal. There are not sterile plants in F1 plants. The different between the fertility of crosses and backcrosses is not marked. The fertile genetic is effected by the nucleus allogene but without cytoplasm. The segregation of the fertility in F2 generation appears sterile, part-sterile and fertile plants. The change of fertility is successive. Conventional studies indicated that the male sterility might be controlled by a numbers of modifiers gene.3. The fertility is restored when these lines are crossed with a number of varieties. The restoring degree has difference among the male parents, and is associated with the ecological type of male parents. The powerful heterosis crosses will be selected and breeded through wide crossing. Planted in different districts can maintain the sterility of these lines.4. The F1 hybrids of these lines are light or non-sensitive to photo-thermo. The fertility of F1 generation is basically normal. The hybrids of these lines used in form producing could be feasible.5. These lines are excellent cross-parents. They are the short straw, the high angle of grain husk, the long duration of flower. The dwarfing genes can reduce markedly the high of male parents straw. They can be used for lodging-resistance in conventional breeding, and dominant dwarfing genes have special advantages for hybrid wheat production.