Vernalization and Photoperiod Requirements for Perennial Grain Crop Intermediate Wheatgrass (Kernza®).

Kate Ivancic and Valentin Picasso University of Wisconsin-Madison Vernalization and photoperiod requirements for perennial grain crop Intermediate Wheatgrass (Kernza¨) Intermediate wheatgrass (Thinopyrum intermedium) bred for increased seed size is a perennial grain crop, known commercially as Kernza¨. International expansion of this promising crop is limited by its adaptation to temperate climates. Moreover, vernalization and photoperiod requirements for Kernza have no been quantified and specific literature on Thinopyrum intermedium induction is sparse. The primary induction requirement for most wheatgrass species is a combination of vernalization and short daylength , followed by long daylength for secondary induction. In order to assess plant flowering response we compared four treatments in temperature and light controlled growth chambers: 1) low temperature (4¡C) during 10 hour days; 2) low temperature (5¡C) during 11 hour days; 3) medium temperature (10¡C) during 10 hour days; and 4) high temperature (26¡C) during 15 hour days, in a randomized complete block design with 2 replications. We tested plants from three different seed origins of Kernza cycle 4 (Minnesota, Wisconsin large seed and Wisconsin regular seed). 18 plants were grown to the four-leaf stage and transferred to treatments for 7-week incubations. Following incubation, plants were returned to the greenhouse and exposed to long days (15 hour days) to complete induction. Plants flowered across all treatments and there was no treatment by seed origin interaction. Low temperature treatments had higher percentage of flowering (80%) than medium (45%) or high (18%) temperature treatments (p<0.05). There were more spikes per plant in the low temperature treatment. These findings suggest potential for selection of Kernza lines with reduced induction requirements. More research for induction requirements is necessary for the advancement and future expansion of this perennial crop.