Oat Varietal Differences in Length of Lower Internodes 1

Six oat, Avena sativa L., varieties grown in sand in a growth chamber were supplied with a complete nutrient solution. Consistent and highly significant varietal differences developed in length of internodes. Although length of internodes was affected by photoperiod, temperature, age, spacing, and planting depth, this is not considered a serious obstacle to use of internode length in varietal purity testing provided environmental conditions can be controlled. Plants of the ‘Russell’, variety grown with continuous light and a temperature of 27 ± 2 C had first leaf internodes (above the first foliar leaf node) three to five times as long as those of other varieties. Second leaf internodes of ‘Orbit’ were nearly twice as long as those of ‘Garry’ or ‘Niagara.’ Both Orbit and ‘Rodney’ had long third leaf internodes whereas ‘Clintland’ had the longest fourth leaf internodes.