Variability in the quality of pollen grains in oat amphiploids and their parental species

Abstract

The pollen analysis has become an important technique to evaluate the use of selectively breeding crops, including the three most important grasses to human nutrition. This study aimed to evaluate the reproductive potential of oat species and their hybrid progeny (amphiploids) during three consecutive vegetation seasons. Correlation and regression analyses were used to describe the morphotypes and viability of pollen grains, while numerical taxonomy methods were applied to analyse the relationships between taxa. The results indicated a difference in the size of pollen grains between the growing seasons, but a stable association between the taxa. The viability of pollen grains showed no correlation with pollen length. In the ordination space, amphiploids and parental species were well discriminated. Amphiploids and parental species were characterised by a positive correlation between the pollen size and the level of ploidy; however, along the respective regression line, the amphiploids were located among species with a high level of ploidy. Developmental anomalies of pollen grains were more frequent in amphiploids, with few pollen grains being chromosomally imbalanced, and the formation of micrograins was the most common event. Multiporate pollens being of multiple-spindle mother cells origin can be equivalents of four monoporate microspores. A strong correlation was observed between the frequencies of multiporate grains and micropollens. In the ordination space, monoporate types (species) were discriminated from multiporate types (amphiploids). High viability of pollen in amphiploids proved their genomic/chromosomal stabilisation across many generations of reproduction.