Microsporogenesis and pollen viability in Physalis ixocarpa

Abstract

The present study aims to describe the behavior of the chromosomes in the microsporogenesis and to estimate the pollen viability in Physalis ixocarpa, for purposes of genetic improvement of the species. Floral buds previously collected and fixed in Carnoy (3 : 1) were analyzed under a microscope after being stained with acetic carmine (1%). The number of cells present in each phase of meiosis I and II were determined: prophase, metaphase, anaphase, telophase and the formation of tetrads. The irregularities observed in each of the analyzed phases were recorded. The Meiotic Index (MI) was calculated. The viability of the pollen was determined according to the level of staining: pollen stained red as viable and yellowish-green or colorless as non-viable. The percentage of viable pollen grains was determined by the number of pollen grains stained by the total number of evaluated pollen ×100. A total of 2256 meiocytes were observed. Of these, 788 meiocytes were measured in meiosis I, 762 cells were observed in meiosis II and 706 tetrads. The calculated MI for P. ixocarpa was 100%, indicating that the species are meiotically stable. The estimated pollen viability for the evaluation of 3600 pollen grains was 93.11% and considered highly viable. In the present study, the presence of pollenkitt adhered to the pollen grains was observed. Thus, the microsporogenesis process is normal, resulting in the formation of highly viable pollen grains.