Principles of Plant Breeding (2+1)

Introduction

• Male sterility is a condition in which pollen is absent and non- functional. There are three types of male sterility.
• Genetic Male sterility: Here nuclear genes condition male sterility in recessive condition.
• Cytoplasmic male sterility: Male sterility is controlled by the actionof Cytoplasm. Since the cytoplasm is transmitted through the female gamete only, cytoplasmically inherited male sterility will be transferred through the female parent. This type of sterility is made use in crop plants where vegetative parts are economically important. E.g. Onion.
• Cytoplasmic Genetic male sterility: It is due to interaction of cytoplasimic and genetic factors. It differs from cytoplasmic male sterility in a way that, a single dominant gene coming from nucleus restores the fertility and can overcome the effect of cytoplasm responsible for sterility.
• Presence of male sterility eliminates the emasculating processes. This has been made, use of in the seed production of hybrid sorghum, bajra, sunflower and onion. The female part is either hand pollinated or allowed for free pollination.
• If the seeds do not develop after crossing the breeder will be in great loss. The failure in seed set is mainly due to the lack of fertility restoration. The term sterility in plant breeding confines only to sterility of the gametophytes, i.e., it is unable to produce viable gametes.
• Even though, the sterility is disadvantageous it could be used advantageously by inducing male sterility, which facilitates easy crossing. Hand emasculation in hermophrodite flowers which are very minute size is a very tedious job and also consumes more time. If male sterility is induced in flowers, it saves time and labour which otherwise would have been used for emasculation and reduces the cost of production of hybrid seeds.

  a. There are mainly three types of male sterility

  i. Genetic male sterility
  ii. Cytoplasmic male sterility
  iii. Cytoptasmic genetic male sterility