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Pinus sibirica and P. pumila are Asian five-needle pines with vast geographic distributions that are partially overlapping. Natural hybrids with intermediate morphology have been found previ­ously, but there is a lack of evidence of ongoing introgression. The goal of our study was to elucidate the genetic structure of P. sibirica and P. pumila populations growing in the north-east of their sympatry zone (Aldan plateau) using cytoplasmic DNA markers. All studied P. sibirica and P. pumila trees had usual spe­cies-specific growth habits. Using nad1 intron2 of mitochond­rial DNA (mtDNA) and trnV of chloroplast DNA (cpDNA) we found that trees morphologically identified as P. sibirica had pumila-specific mtDNA. Moreover, some of them also had pumila-specific cpDNA. P. pumila trees were typical and had pumila-type cytoplasmic DNA markers. These results suggest that interspecific hybridization took place long ago and lead to introgression and cryptic hybrids with P. sibirica appearance and P. pumila mtDNA

Currently, the development of highly productive sorghum hybrids with a high content of the main nutritional components in grain is of great relevance. The current paper has presented the estimation results of the effects of true and hypothetical heterosis on percentage of protein, oil and starch in grain of the first-generation hybrids. There have been analyzed 54 combinations obtained on the basis of three CMS-lines and 18 pollinators. The components of the hybrids and their progeny were grown on the FSBSI RosNIISK “Rossorgo” experimental plots of 7.7 m2, in triple sequences with plant density of 100 thousand plants per ha. The biochemical composition of the grain was determined by the SpectraStarXT infrared analyzer. The parental components and their progeny differed in the biochemical composition of grain, which was confirmed by the analysis of variance. There was identified a slight variation of the ЗерновоехозяйствоРоссии № 2(68)’ 2020 50trait ‘starch content’ in maternal and paternal forms of the hybrids F1(V= 2.5–8.3%). There was identified an average variability of protein percentage in the initial forms (V= 7.9–14.6%) and a weak variability in hybrids (V= 9.1–10.8%). There were identified larger values of variation of oil content (9.0–17.2%). The manifestation frequency of true and hypothetical heterosis of protein percentage was identified in 31.5–62.9% and 44.4–79.6% of hybrids; of fat content was identified in 20.4–57.4% and 20.4–75.9% of hybrids; of starch content was identified in 16.6–33.3% and 16.6–44.4% of hybrids. A focused approach in breeding the varieties with the improved biochemical components of grain allowed us to identify 9 combinations characterized by the annual effect of heterosis in protein content (4 combinations), in raw oil accumulation (2 combinations) and in starch accumulation (3 combinations).

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