Interrelations between the main seed quality characteristics of narrowleaf lupine from the VIR collection

The widespread use of narrowleaf lupine (NLL, Lupinus angustifolius L.) as a feed and food crop requires source material for breeding cultivars with high-quality seeds. The priority criterion for attributing NLL cultivars to the feed or food category is the content of alkaloids. At the same time, equally important seed quality indicators are the protein and oil content, as well as moisture content, which determines the possibility of long-term storage of seeds. For the first time in Russian lupine science, an attempt was made to study the relationships between all the listed characteristics of narrowleaf lupine seeds under the conditions of Northwest Russia (Pushkin town). Sixty-two accessions from the VIR collection were studied in 2019, 2020 and 2022. The range of variability of the studied characteristics was 27.8-37.6 % for protein, 3.9-7.3 % for oil, 1.6-2017.4 mg/100 g of dry matter (D.M.) for alkaloids, and 6.4-7.3 % for moisture. A significant negative correlation between the oil and protein content (-0.33) was observed only in 2019. No significant correlations between the protein and alkaloid content were found in the studied sample. Significant negative relationships were identified between the content of oil and alkaloids only in 2019 and 2020 (-0.38 and -0.27, respectively). In 2022, no correlations were identified. Obviously, the identification of regularities in these correlations requires many years of research taking into account weather conditions. The influence of weather on the concentration of alkaloids in seeds has been proven. The average amount of alkaloids for the sample in 2019 was 504.2 ± 77.7 mg/100 g D.M., 263.7 ± 38.6 mg/100 g D.M. in 2020, and 319.8 ± 51.4 mg/100 g D.M. in 2022. It confirmed the data previously obtained by the authors that the content of alkaloids in seeds increases significantly along with the precipitation deficiency. The temperature regime during this research did not affect this indicator. An increased air temperature contributed to the accumulation of oil, and an increase in precipitation contributed to the accumulation of protein. The most stable indicator independent of environmental conditions was the seed moisture. Accessions with the optimal combination of the main biochemical parameters that determine seed quality have been identified for breeding narrowleaf lupine cultivars in the region in question for feed and food purposes, as well as for green manure.