Florogenesis and Female Gametophyte Development in <i>Allium cepa</i> L. cv. Krishnapuram

Abstract

Florogenesis is one of the most complicated and interesting processes in the nature. This process involves developmental, physiological and molecular events leading to transformation from vegetative to reproductive phase for optimal seed production and the continuation of species. The basic knowledge about flowering processes, male and female sexual systems support basic and applied research and breeding programs. Most of the onion varieties from India are short day varieties, more diverse than other exotic germplasm and useful as a source of new alleles for supporting breeding programs. The present investigation was focused to study for the first time florogenesis process by scanning electron study for the first time florogenesis process by scanning electron microscopy (SEM) and development of female gametophytes by light microscopy in order to acquire basic knowledge useful for optimizing in vitro process to produce gynogenic haploid to support and speed breeding program in short-day onion Allium cepa L. cv. Krishnapuram (KP) or Bangalore Rose.This study revealed that shoot primordium differentiated into inflorescence meristem in the month of December, while seeds were planted in the field in the September. The individual florets are preceded by a variying number of floral initials. The female gametophyte developed from chalazal side megaspore. The embryo sac development is a bisporic Allium type showing shortlived antipodals. The histological study suggests that the use of big or preanthesis flower buds with embryo sac for production of gynogenic haploids to support breeding program in onion cv. Krishnapuram (KP). However further studies are needed for confirmation of this observation.

Shallot Species and Subtypes Discrimination Based on Morphology Descriptors

“…In addition, the number of flowered plants ranged from around 0% for a few accessions (IPT022, IPT215, and IPT216) to more than 70% of flowered plants in the majority of accessions. The lack of uniform flowering can be attributed to the dependence of florogenesis on both genetic and environmental factors [ 2 , 22 , 31 , 32 ]. The flowering function in shallots of the A. cepa Aggregatum group has been associated with shLFY genes based on which shallot genotypes occur as either a naturally flowering type (abundant, obligate flowering), inducible flowering type (by favorable environmental factors) or non-flowering genotypes [ 33 ].…”