Variation in Photoperiod Sensitivity for Time of Flowering and Maturity Among Soybean Strains of Maturity Group III1
- C. R. Nissly2,
- R. L. Bernard3 and
- C. N. Hittle4
In field screenings at Urbana, Illinois, in 1973 and in Puerto Rico in 1974-75, soybean [Glycine max (L.) Merr.] strains of Maturity Group III exhibited a wide range in sensitivity to photoperiod. Several hundred strains were grown under natural day length, and the same strains were grown nearby under a photoperiod extended with incandescent light to either continuous light or with a 5-hour interruption of the night. All strains grown under the extended photoperiod eventually flowered, but they showed a wide range in delay compared with those under natural day length. The frequency distribution of strains with respect to the length of delay approached a normal curve. At Urbana, extended photoperiod delayed flowering from -2 to 60 days. Of 515 strains, 25 were delayed less than 15 days and 5 were delayed more than 55 days. By first frost, 172 days after planting, 24 lines had matured under extended photoperiod. In Puerto Rico, flowering was delayed from 3 to 85 days by a continuous photoperiod. One strain was delayed less that 10 days and 3 were delayed more than 80 days. When the experiment was terminated at 235 days, 285 of the 439 strains were mature and 7 had matured within 170 days. Thirty-two strains were identified as having low photoperiod sensitivity, and one of these, PI 317.334B (‘Kitami Shiro’), exhibited almost no photoperiod sensitivity at either location.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .