Method to Evaluate Pollen Viability of Upland Cotton: Tests with Chromosome Translocations

Abstract

Cytogenetically induced semisterility can provide a useful phenotype to facilitate many sorts of genetic and cytogenetic manipulations that otherwise require meiotic analyses. Most chromatin deficiencies are not pollen‐transmissible in Upland cotton (Gossypium hirsutum L.) due to reduced viability. A quick and reliable technique for the assessment of cotton pollen fertility has not been established. A modified fluorochrome reaction (FCR) method, using fluorescein diacetate, was evaluated for application as a pollen viability/fertility indicator by scoring fluorescence of pollen from normal and reciprocal chromosome translocation cytotypes grown in greenhouse and field environments. Analyzed materials included 44 different true‐breeding translocation homozygotes, respective F1 heterozygotes, and three different cytogenetically analyzed BC1F1 families. Translocation heterozygotes consistently produced higher frequencies (12.3–38.8%) of less intensely fluorescing pollen grains than homozygotes (0.4–6.4%) or normals (0.4–4.0%). Results were concordant with cytogenetic expectations and meiotic analyses, indicating that these and perhaps other cytogenetically aberrant types of cotton can be discerned phenotypically on the basis of percent pollen viability, thereby facilitating their detection and use as cytogenetic tools.