Flowering time in soybeans is controlled by day length. Soybean plants will flower early during short days and will flower late during the long days of summer. Previous research has indicated that early flowering was the default condition when a plant either has no late flowering genes or is grown in short days. Late flowering occurs when late flowering genes are present in a plant and when they are activated by long days.
For this study, conducted from 2000-2002, scientists grafted soybean plants using a combination of early and late flowering plants and grew them under long days. Early flowering shoots flowered early regardless of the rootstock. This early flowering was seen even if the shoots were defoliated. Early flowering rootstocks speeded the flowering of grafted late flowering shoots. The full results of the study are published in the May/June issue of Crop Science.
"It was surprising to find that early flowering was a much more active process than we initially predicted. Early flowering grafts remained early flowering when grafted to late flowering rootstocks even when we removed the leaves. It appears whatever promotes flowering might be sensed in small, developing leaves or even buds. The control of flowering time in soybeans is complex and still is not well understood," said Elroy Cober, project leader.
For soybean producers on the northern fringe of Canada, early flowering and maturity are of primary importance. Further research into what controls early flowering will assist in the development of cultivars reliably adapted to these short growing seasons.
Crop Science Journal, http://crop.scijournals.org is a peer-reviewed, international journal publishing original research in crop breeding, genetics, and cytology; crop physiology and metabolism; crop ecology, production, and management; seed physiology, production, and technology; turfgrass science; crop ecology, management, and quality; genomics, molecular genetics, and biotechnology; plant genetics resources; and pest management.
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