Stabilization and maintenance of male sterility percent in recessive genetic male sterile line.s of safflower (Carthamus tinctorius L.)

Abstract

The development of a stable recessive genetic male sterile line MS 9(0) [1) has led to release of the first safflower (Carthamus tinctorius L.) hybrid - DSH 129 for commercial cultivation in India (2). Several genetic male sterile lines were developed later on in safflower by transferring the recessive male sterility gene in agronomically superior lines. It is well known that in a genetic male sterility system, male sterility and fertility segregate in 50 : 50 ratio. The degree of male sterility in a sterile plant is 100% in a genetic male sterile line of safflower. Therefore, the male sterility percent of a genetic male sterile line is directly proportional to number of male sterile plants. The frequent problem faced by many safflower breeders in maintenance of a recessive genetic male sterile line is reduction in proportion of male sterile plants. Considering this problem, the method of stabilization and maintenance of recessive genetic male sterile parent MS 9(0) of the hybrid DSH 129 is discussed in this paper, which could also be applicable for other recessive genetic male sterile lines in safflower to maintain high proportion of male sterile plants in their maintenance blocks.