Principles of Plant Breeding (2+1)

Cytoplasmic Genetic Male Sterility

• This type of sterility differs from cytoplasmic sterility only in that the off spring of male sterile plants can be male fertile when certain stocks are used as pollinators. Thus, cytoplasmic sterile plants are converted to fertile plants by crossing with the plants with restorer genes.
• Production of sorghum hybrids is possible through utilization of cytoplasmic genetic male sterility.
• MSJCK 60 A (Male sterile combining kafir 60)is a male sterile line of sorghum, which contains the kafir chromosomes.
• Inbred lines are converted to male sterile lines by a number of back crosses using MSJCK 60 or any male sterile as female parent and inbred line to be converted as recurrent pollen parent. The newly synthesized male sterile inbred line is designated as line A. The original male fertile line is designated as line B. There is no other difference between A and B lines except that A is male sterile and B male is fertile, which should be a pollen producing line.
• Line A is grown in an isolated field and it is wind pollinated by B. Thus male sterile line A will be maintained generation to generation. Line B is maintained by self pollination Male sterile inbred line A is grown in an isolated field and wind pollinated by unrelated inbred R which is male fertile line which possess pollen restoring genes.
• The seeds of the above single cross may be sold to farmer with the advice not to take advance generation from the year grown plants.