Lj. Armstrong et Sw. Adkins, VARIATION IN PHOTOPERIOD RESPONSE OF DIFFERENT ISOGENIC LINES OF WILDOATS (AVENA-FATUA), Weed science, 46(1), 1998, pp. 39-47
For wild oats, persistence characters such as seed production and seed
dormancy may be affected by generic variation and several environment
al factors during the development of the parental plant. However, the
effect of varying photoperiods on such characters is unclear. Previous
studies have concentrated on natural populations and have nor studied
the genetic variability within the population. Consequently a study w
as conducted to examine how photoperiod (10, 12, 14, 16, and 18 h at 2
0 C) influenced the persistence of different members of a synthetic po
pulation of wild oats. This synthetic population consisted of several
isogenic lines with differing degrees of seed dormancy that originated
from one region in North America. All lines were photoperiod sensitiv
e, quantitative long day planes, with an increase in time to maturity
for all lines (about 78 to 213 d) when photoperiod was reduced from 18
to 10 h. The lines within this synthetic population (with the excepti
on of one, M73) showed a similar degree of photoperiod sensitivity. Th
is may be expected, as the lines are from one region with the same pho
toperiod environment. It could be concluded that such a photoperiod se
nsitivity is a beneficial character that has allowed persistence of th
ese lines in this region. When photoperiod was reduced from 18 to 10 h
, plants produced fewer seeds (about 141 to 61 primary seeds per plant
) with a higher degree of seed dormancy (about 88 to 54% germination i
n 10(-4) M gibberellic acid; GA(3)). The reduced seed production under
the shortest photoperiod (10 h) was due to poor panicle exsertion, wh
ich resulted in poor development of basal florets. There was no consis
tent relationship between photoperiod and other plant characters such
as tiller production, caryopsis weight, and water content. However, si
gnificant relationships were found between seed dormancy characters an
d other plant characters such as maturity time, caryopsis weight, and
water content under certain photoperiod treatments.