Features of the formation of sowing qualities of white lupine seeds depending on the harvest time

Abstract

Purpose. To determine the optimal time for harvesting in nurseries of primary seed production of white lupine.

Methods. Field, laboratory and statistical methods of material evaluation were used. Sowing qualities were studied in the laboratory separately for seeds from the central and lateral racemes in accordance with DSTU 2240-93 (State Standard of Ukraine).

Results. The results of studies on determination of optimal terms for harvesting in nurseries of primary seed production are given. The studies were conducted separately for seeds from the central and lateral racemes collected in different ripe stages. It was established that the seed vigor during the first harves­ting time was minimal and ranging for varieties from 70.0 to 73.0% for the central raceme and from 58.0 to 65.0% for the lateral racemes. The best indices of seed vigor and germination capacity were established in the seeds of the central racemes harvested during the “yellow cotyledon” stage. They averaged 90.8 and 94.3% respectively for all varieties, while in the seeds of the lateral racemes these indices amounted to 84.5 and 89.3%. Agrometeorological conditions had influence on the thousand-kernel weight formation. In dry years, plants produced feeble and lightweight seeds, so their sowing qualities has been deteriorated. The highest thousand-kernel weight was obtained in the “full ripeness” stage, when it ranging from 284 to 338 g in the central racemes and from 266 to 316 in the lateral ones. The development of embryonic roots including external appearance, length was assessed. Visual assessment of germination on the third day and measurement of the length of embryonic roots on the seventh day showed that healthy, well-developed seedlings were observed in seeds of the fifth and sixth harvesting periods.

Conclusions. The highest sowing qualities in most varieties with regard to lateral racemes were established in the seeds harvested in the «full ripeness» phase. For the germinating capacity, seeds of the central raceme met the requirements of DSTU for the additional category (87.0%), starting from the stage “beginning of the embryonic root yellowing”, but seeds of the lateral racemes not earlier than the phase of “yellow cotyledons”. Harvesting should be started at the “yellow cotyledons” phase of lupine seeds maturity when they were fully formed and have high sowing qualities.