AAC Richelieu

Lettuce

Variety Description

Varieties used for comparison: 'Ithaca', 'AAC Champlain' and 'Hochelaga'

Summary: The outer leaf of 'AAC Richelieu' has a transverse broad elliptic shape whereas that of 'AAC Champlain' has a transverse narrow elliptic shape and that of 'Hochelaga' is circular. At harvest maturity, 'AAC Richelieu' has a shorter stem than that of 'Ithaca'. In cross-section, the head of 'AAC Richelieu' has a wider diameter than that of 'Ithaca'. At flowering, the plant of 'AAC Richelieu' is shorter than the plant of 'Ithaca' and taller than the plant of 'AAC Champlain'. Under long day conditions, bolting begins late in the season for 'AAC Richelieu' whereas 'Ithaca' begins bolting mid-season. When cultivated during hot summer growing conditions, the incidence of tipburn on the leaves of 'AAC Richelieu' is low whereas it is high on the leaves of 'Hochelaga'.

Description:

PLANT: closed head type, absent or very weak axillary sprouting, bolting begins late under long day conditions, early to mid-season harvest maturity

SEEDLING: no anthocyanin colouration, no division of leaf blade at 10 to 12 leaf stage

HEAD: closed head formation with strong degree of overlapping of upper part of leaves, dense, circular shape in longitudinal section

LEAF: medium thickness, semi-erect attitude at harvest maturity, transverse broad elliptic shape, obtuse tip, medium green outer leaves, no anthocyanin colouration, moderate to strong glossiness on upper side, weak degree of blistering, small blisters, medium degree of undulation of margin, flabellate (fan shaped) venation
INCISIONS OF MARGIN ON APICAL PART OF LEAF: medium to dense, very shallow to shallow, dentate

SEED: black seed coat

Origin & Breeding History: 'AAC Richelieu' (experimental designations 'X2617' and 'QSJ-10') originated from a cross conducted in November of 2004 between the F4 line [('Summertime x Eldorado') F4 X ('Summertime' x 'Onondaga') F5], as the female parent, and the F6 line ('Valley Green' x 'Ithaca'), as the male parent, in the greenhouses of the Agriculture & Agri-Food Canada Horticultural Research and Development Centre in Saint-Jean-sur-Richelieu, Québec. The resulting F1 seeds were planted in the greenhouses in December of 2004 and the F2 seeds were collected and bulk massed in June of 2005. From 2006 to 2008, successive generations were grown and harvested at the Sainte-Clotilde experimental station and at a muck soil farm in Napierville, Québec. The selections from each were based on good 'Great Lakes' type characteristics combined with size, weight, firmness, low ribbiness, short stem and lack of symptoms of rib discolouration and tipburn. In 2009, F5 seedlings were transplanted and evaluated. From 2010 to 2012, single plant selections continued on the F6 to F8 plants. During 2012, F8 seeds were planted in single plant progeny rows in the San Joaquin Valley in California for seed evaluation and multiplication. Single plants were selected and F9 seeds were collected from individual plants, the remainder of which were bulk massed after harvest in September of 2012. Additional trials were conducted from 2013 to 2015. In December of 2015, the new variety became known as 'QSJ-10'.

Tests & Trials: The comparative trials for 'AAC Richelieu' were conducted at the JPL Guérin Farm, in Sherrington, Quebec, during the summers of 2015 and 2016. Both the candidate and reference varieties were sown in the greenhouse and later transplanted into fields of organic soil. Each variety was planted in four randomly planted plots. The plots were composed of two rows spaced 35.5 cm and planted in mounds that were 14.6 metres long and 0.91 metres wide. Each plot contained 80 plants resulting in a total of 320 plants per variety. The plants were grown under normal conditions for cultivation with long days (photoperiod between 15 and 16 hours per day). The lettuce was harvested and evaluated at the time of optimal maturity during the last 2 weeks of July. For each trial year, measured characteristics were based on measurements of at least 12 plants per replicate for a total of 48 plants per variety per year except for the plant height at flowering which is based only on a total of 20 plant measurements per variety per year. Mean differences were significant at the 5% probability level based on LSD values.

Comparison tables for 'AAC Richelieu' with reference varieties 'Ithaca', 'AAC Champlain' and 'Hochelaga'

Head diameter in cross-section (cm)

Length of stem (from base of first external leaf forming head to apical bud) (mm)

Plant height at flowering (cm)

Click on image for larger view

Lettuce: 'AAC Richelieu' (right) with reference varieties 'Hochelaga' (left), 'AAC Champlain' (centre left) and 'Ithaca' (centre right)