Floral quality in third-generation descendants of outstanding gladiolus cultivars obtained by gamma irradiation

Abstract

The gladiolus is one of the most commercially important cut flowers in Mexico. It was traditionally considered a funeral flower, but its uses have now diversified to many other decorative floral arrangements due to its variety of colors and forms. All the    new varieties on the market in Mexico are of foreign origin, such that the generation of new genotypes is needed. In a previous study, flowers originating from irradiated Blanca Borrega variety corms expressed different floral characteristics, shape and size; however, it is unknown whether these characters are fixed in subsequent generations. The objective of the current work was therefore to evaluate the fixed characteristics in the ornamental quality of outstanding cultivars of Blanca Borrega variety gladiolus descended from irradiation with 60Co. During the fall-winter (2020-2021) period, corms of outstanding cultivars generated by distinct irradiation doses were planted in sterilized substrate to evaluate corm germination (%), plant height, number of leaves per stem, spike length (cm), combined stem and spike length (cm), number of flowers per spike, flower size (cm), number of leaves, and survival, and to categorize cut flower quality under the United Nations Economic Commission for Europe (UN/ECE) criteria. Our results indicated that the outstanding cultivar derived from the 80 Gy dose presented a Class I classification (Second quality) of the UN/ECE parameters due to its stem height and number of buds, followed by the cultivars descended from irradiation at 10, 30 and 50 Gy and the control, which were placed in Class II (Third quality). Thus, in the third generation the favorable esthetic characteristics of the outstanding cultivars remain fixed.