Cold-resistance of modern varieties proso millet of ukrainian breeding

The article presents the results of studying 43 modern varieties and lines of proso millet from breeding institutions of Ukraine for the cold resistance. Statistically analyzed that the proso millet genotypes recorded significant differences the seed germination percentage and root length on 12 and 20 days in low positive temperatures (t = 7 °С). The level of cold resistance of millet genotypes is also shown in comparison with Kharkivske 57 (control). Ability of continued elongation of root under situation of cold stress is shown. Identifying the superior genotypes for the further millet breeding for cold resistance (Lana, Novokyivske 01, L. 08-4264).

percentage and root length of millet were measured on days 12 and 20. Seeds were considered as germinated, if roots were not shorter than 0.5 mm. Kharkivske 57 was used as the check variety.
Results and discussion. The experiment design was completely randomized with two factors. The first factor was germplasm; the second factor -time. The data were analyzed by ANO-VA, and means were compared using LSD with P<0.05. We used GenStat 9 software (VSN International Ltd, 2009) for statistical processing.
There were significant differences on different days for all the characters under investigation (Table 1). All the millet varieties and lines could be categorized into 5 cold resistance groups: group 1 -susceptible; group 2 -weakly resistant; group 3 -moderately resistant; group 4 -with aboveaverage resistance; group 5 -highly resistant. The data on cold resistance categorization of the varieties and lines on days 12 and 20 are presented in Table 2. On day 12, most of the millet varieties were weakly resistant: 77% of the varieties and lines were assigned to groups 1-3. Only two varieties, Lana and Novokyivske 01, and line L. 08-4264 were highly resistant -group 5. Seven 7 varieties showed above-average cold resistance. Thus, there were significant differences in the seed germinability between the varieties on day 12. On day 20, the categorization of the genotypes visibly changed. Most of the varieties (as many as 77%) were highly resistant or showed above-average resistance, suggesting that modern millet varieties are adaptable to low above-zero temperatures, despite the slowdown in growth processes. Table 3 presents the seed germinability dynamics of the genotypes with high resistance to low above-zero temperature on day 12. Their level of cold resistance related to the check variety exceeded 200%. For example, it was 257% in variety Lana; 209% in variety Novokyivke 01; and 239% in line L. 08-4264. These accessions also formed roots more intensively and had longer roots. The root length in Lana exceeded that in Kharkivske 57 by 6 mm. The data showed that despite the fact that millet is a drought resistant crop, widely disseminated across the semiarid tropics of Africa and Asia, there were millet varieties with high cold resistance. In our study, under cold stress on day 20, genotypes Lana, Novokyivske 01 and L. 08-4264 had longer mean root length compared to the check variety. Lana"s roots were 22 mm (+12 mm) long; Novokyivske 01"s -20 mm (+10mm) long; and L. 08-4264"s -18 mm (+8 mm) long. Early and rapid elongation of roots is an important indicator of cold resistance. Thus, we recommend using these genotypes as starting material for breeding for adaptability.

Conclusions.
Our results show that, despite the fact that millet is a thermophilic crop, it is possible to develop new varieties that will be characterized by high resistance to such a stress factor as cold.
Results and discussion. On day 12, millet accessions were poorly adapted: 77% of the varieties and lines were classified as susceptible or weakly resistant. Only two varieties (Lana and Novokyivske 01) and line L. 08-4264 had above-average resistance. On day 20, the genotypes categorization changed, and most of the accessions (77%) were highly resistant or showed aboveaverage resistance. The article describes the seed germinability dynamics of genotypes showing high resistance on day 12. Their cold resistance exceeded 200% related to the check variety: 257% -in variety Lana; 209% in Novokyivske 01; and 239% in line L. 08-4264. These accessions also formed roots more intensively; their roots were longer than those in variety Kharkivske 57 by 1 -4 mm. The article presents varieties and lines that on day 20 were not only highly resistance to cold in comparison with the check variety (100-113%), but also were superior to Kharkivske 57 in terms of the sprout root length by 8 -13 mm.