Comparison of reproductive organs structure in various genotypes of Phaseolus vulgaris grown under the same conditions in Mersin, Turkey

The common bean (Phaseolus vulgaris) is a plant having hermaphroditic flowers, which are self-fertilizing. Common bean is a important commercial crop and one of Turkey’s most valuable grain legumes for human consumption. Genetic variation exists within and between bean populations. These variations can have an impact on the plants morphology, including reproductive organs. Variations in size and length of reproductive organs may cause different cell numbers and various fertilization successes. In this study, the response of four determinate common bean genotypes (Akman, Bitlis 117, Göksun, and Karacaşehir) to reproductive organ structure was studied. Plants were grown at 21/16 °C (day/night) and 12 h photoperiod in a greenhouse in Mersin, Turkey. Besides focusing mainly on pollen development, fertilization success factors such as pod and seed set were also assessed. Pod and seed set were evaluated numerically for each genotype. For pollen morphology, flower buds of the equal growth stage of all four bean genotypes were collected, and these samples were analyzed by scanning electron microscopy. The species have distinct morphological characteristics concerning pollen size, ornamentation patterns of the exine, and endoaperture type. It is also crucial to examine pollen dispersion in the pollinated flowers, as it may influence reproductive success. However, pollen wall architecture was similar in all genotypes tested. Despite general morphological similarity, differences in pollen viability and pod and seed number were observed. Although Akman genotype had the largest flowers, the Karacaşehir genotype was found to be the most productive one. The findings presented here can be helpful for researchers studying bean breeding and those investigating the morphological variation in different Phaseolus genotypes.