Formation of Seed Quality of Switch-Grass (Panicum virgatum L.) Depending on Cultivation Conditions and Varietal Peculiarities

Abstract

The results of the research concerning the formation of seed quality depending on the cultivation conditions and varietal peculiarities were presented in the paper. Analyzing seed quality in the years under study, it was found out that germination energy and seed emergence depended both on ripeness groups of switch-grass and the sum of effective temperatures in the vegetation period. The highest quality indicators were typical for an early cultivar (Dacotah), an early-ripening cultivar (Forestburg) and average-ripening cultivars (Nebraska, Sunburst); a reliable difference depending on varietal peculiarities was not recorded. Varietal samples of average-late ripening cultivars (Alamo, Cave-in-rock) had reliably lower quality indicators, and a very-late ripening cultivar Kanlow had the lowest ones. In the conditions of the Forest-steppe of Ukraine average-late, late and very late varietal samples do not ripen biologically which affects seed quality – its emergence is very low and amounts to 6-26%. By the years under study, the highest reliable germination energy and emergence of all varietal samples, particularly in a late ripeness group, were recorded in the vegetation year of 2018, and they amounted to 33-66% and 17-25%, respectively, which was predetermined by the sum of effective temperatures – over 3539 0С. Much lower indicators of seed quality were received in 2021, this year was the least favorable for the formation of high-quality seed, and the sum of effective temperatures was only 3080 0С. The conclusion can be made that in the period of vegetation the formation of quality seeds of switch-grass depended on the sum of effective temperatures which was lower than 3300 0С. It has been established that the later a ripeness group is, the larger sum of effective temperatures a varietal sample requires, and accordingly, a longer term for the occurrence of phonological phases of crop growth and development; this has an effect on the peculiarities of the seed formation and ripening and in turn on its quality. It was found out that the factor “the conditions of the year” had the highest effect on seed quality – 48%, and the factor “varietal sample – ripeness group” had the lowest one, namely 29% and 30%, respectively.

Keywords

• varietal sample
• germination energy
• emergence
• phonological development phases
• ripeness group