Early Plant Development in Intermediate Wheatgrass

Abstract

Early seedling developmental morphology influences plant growth and development and ultimately crop biomass and grain yields. We used six half-sibling plants of intermediate wheatgrass (IWG) (Thinopyrum intermedium, (Host), Barkworth and Dewey) to develop an obligate outcrossing species, to develop six maternal lines. Thousand seed weights (TSW) were consistently different amongst plants, averaging from 6.28 to 9.62 g over the three harvest years. Seedlings from the largest seed of each line were studied for early plant development under controlled conditions (22 °C/18 °C, 16/8 h day/night) with destructive harvests at 21, 28, 35 and 42 days after imbibition (DAI) through six grow-outs. Haun stage, and tiller umber and origin, were noted daily, and dry weight plant−1 (DWP) measured at the dates noted above. Leaf-blade length and width were measured in four grow-outs and leaf area estimated. Seedling development data showed some differences between lines and was similar in all lines studied. Data was combined to garner an understanding of early IWG development. Tillering began as the third leaf completed emergence. Coleoptile tillers and rhizomes were infrequent. DWP was best estimated using the main stem leaf area. A large-, a medium- and a small-seeded line were statistically identical for many characteristics including DWP indicating that TSW did not influence seedling vigor. The main stem leaf area may be used non-destructively to improve plant populations for early DWP selection.