Study of the vegetation period length and the height of the plants of accessions from the national collection of millet (Panicum miliaceum L.) and their relationship with the yield for the conditions of Central South Bulgaria

The aim of the current study is to establish the duration of the vegetation period, differences in height and the connection between these two indicators with the productive potential of the accessions from the national millet collection for the conditions of southern Bulgaria. The study was done on 394 accessions from the collection. A comparative varietal trial was also set, including 8 selected accessions with different vegetation period and height to establish their yields in field conditions. The samples were studied according to the international descriptors for the species Panicum miliaceum L., and the experiment was done in the period 2022 - 2024 according to the block method, in four replications with 10 m2 of harvest area. The research was carried out in the experimental field of IRGR Sadovo. It was found that in the conditions of Central South Bulgaria, the different accessions of millet ripen in an average of 62 days. The variation of specimens in height is very significant, ranging from 51.8 to 146.0 cm. The studies showed that 31 of the accessions yielded more than 5 g per panicle, indicating that they have high and very high yield potential. The results from the correlation analysis shows that there is a strong correlation between yield and vegetation period, but there is no correlation between yield and plant height. The results confirm that yields are influenced much more by the weather conditions, and the best results are shown by accession No. A6000097. For the conditions of Central South Bulgaria, yields of 3000 to 4000 kg/ha can be expected from it as a first crop under non-irrigated conditions.