TITLE:
Bolting and Flowering Response of Lactuca georgica, a Wild Lettuce Relative, to Low Temperatures
AUTHORS:
Alex Beharav, Barbara Hellier
KEYWORDS:
Gene Pools, Lactuca sativa, Phenological Adaptation, Plant Age, Vernalization Duration, Wild Lettuce
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.11 No.12,
December
31,
2020
ABSTRACT: To learn about the phenological adaptation of Lactuca georgica Grossh., a wild
relative of domesticated lettuce, we studied seed sampled accessions obtained
from individual plants at 19 locations throughout six regions in Armenia, and
from two natural populations in Dagestan (Russian Federation) collected as bulk
samples. The effects of various vernalization treatments on time to bolting,
flowering and seed production time were investigated during four successive
years at different growth stages of L. georgica plants. We demonstrate that low temperatures
play a major role in stimulating the reproduction process of L. georgica plants. Our results
would suggest that for L. georgica:
1) There is an obligatory (or nearly so) vernalization requirement; 2) Plant
age, vernalization duration, and genotype of original sample have a role in
bolting and flowering regulation; 3) Some plants behaved as typical annuals,
responding to vernalization treatment at the seedling stage, but, most did not;
4) Four months of vernalization could be adequate to reach bolting in plants
with a developed vegetative rosette, for most—but not all—samples; 5) In order
to find the best solution for stimulating the reproductive process of multiple
genotypes, it seems that further study should focus on about 4 - 6 months of
vernalization at 4°C applied to plants of about 10 - 22 months old vegetative
rosettes, with controlled post-vernalization condition; 6) L. georgica germplasm could be
used as a source for delayed bolting in breeding of domesticated lettuce
varieties.