New Zealand Journal of Crop and Horticultural Science
abstracts
Genetic analysis of sweetness and textural attributes in winter squash (Cucurbita
maxima)
Paul L. Hurst
Virginia K. Corrigan*
New Zealand Institute for Crop & Food Research Limited
Private Bag 11 600
Palmerston North, New Zealand
email: corriganv@crop.cri.nz
John Koolaard
AgResearch Grasslands
Private Bag 11 008
Palmerston North, New Zealand
Abstract Quantitative genetics of chemical and textural attributes
of quality of winter squash (Cucurbita maxima) were studied using the
F1, F2, and backcrosses of the two crosses ‘Scarlet Warren’ ´ ‘CF2’ and ‘Scarlet
Warren’ ´ ‘CF4’. The 3-parameter additive-dominance
model adequately explained the variation among generation means of ‘Scarlet
Warren’ ´ ‘CF2’ for dry matter (DM), alcohol-insoluble
solids, sucrose, glucose, fructose, soluble pectin, springiness, and adhesiveness
but failed with total pectin, fracture hardness, and cohesiveness. Among generation
means of ‘Scarlet Warren’ ´ ‘CF4’, the model explained
the variation in all attributes except DM and springiness. Additive gene effects
were negative for DM, alcohol-insoluble solids, sucrose, soluble pectin, and
adhesiveness but positive for glucose, fructose, total pectin, and springiness.
Dominance gene effects were negative for alcohol-insoluble solids and total pectin
but positive for all three sugars, soluble pectin, springiness, and adhesiveness.
Low heritability for most attributes other than sucrose indicated that environmental
impacts (attributed to different growing climates for the two sites used for
this study) were larger than genetic effects. Thus, breeding to produce sweeter
squash is feasible, but breeding for textural improvement would seem to be problematic
because the environment has an overriding effect on textural attributes.
Keywords buttercup squash; Cucurbita maxima; generation
means analysis; heritability; sweetness; texture; winter squash
New Zealand Journal of Crop and Horticultural Science, 2006, Vol. 34:
359–367
0014–0671/06/3404–0359 © The Royal
Society of New Zealand 2006
*Author for correspondence. H06033; Online publication date 20 November 2006.
Received 4 April 2006; accepted 4 October 2006
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