Genetic Variation in Among Seed Vigor of Single Crosses and Top Cross Hybrids of Sugar Beet

Germination and seedling emergence potential of monogerm sugar beet seed in the field, depends on seed quality. Also, crop yield and resource use efficiency of agricultural inputs depend on successful plant establishment in the field, and it is the vigor of seeds that defines their ability to germinate and establish seedlings rapidly, uniformly, and robustly across diverse environmental conditions. Our knowledge of variation in vigor and function of seed in crop yield, is limited. Accordingly, the quality characteristics of seeds, including seed vigor, are essential in the process of sugar beet breeding to provide cultivars with vigor and seed function good in the field. The present study was conducted to evaluate and rank single crosses and hybrids being improved in terms of different traits of seed vigor and determining the relationship between them to achieve maximum seed quality.

In this study, the seed vigor traits of 22 single crosses and 22 top cross hybrids, from crossing along with the sugar beet pollinating line, under greenhouse conditions in Sugar Beet Seed Institute in 2020-2021 were studied. The quality traits of single crosses and hybrids in two separate experiments in greenhouse conditions, each with 22 treatments were evaluated in a randomized completely block design with four replications.

The results showed that seedling emergence traits in single crosses and top cross hybrids resulting from their crossings in sugar beet were influenced by genotype. Genetic variation was observed between single crosses and hybrids in terms of seed vigor. Hybrids with low abnormal germination percentage, low non-germinated seeds and high germination uniformity in the laboratory have a significant increase in seedling emergence compared to other hybrids. Finally, hybrids that high germination uniformity in the laboratory, had the higher coefficient velocity of germination and were green in less time.

It seems that the uniformity trait of sugar beet seed germination has a decisive and significant role compared to the rest of the quality traits in the laboratory and can be used in breeding programs as an index of seed quality selection; Also, the multivariate cluster analysis method and the ideal genotype selection index (SIIG) of genotypes based on the qualitative traits of sugar beet seeds (seedling emergence percentage, seedling emergence rate, mean emergence time of seedling, emergence uniformity of seedling, mean dry weight of seedling) obtained a statistically significant difference in the cluster and their ranking in SIIG. It seems that the germination traits of sugar beet seeds can be used in breeding programs as one of the indexes of seed quality selection; Therefore, it is expected that selecting and screening superior genotypes to increase the quality of sugar beet seeds, it will lead to the improvement and increase of seedling emergence in the field and finally, will be accompanied by an increase in crop yield.