Cucurbit Genetics Cooperative Report 10:90 (article 48) 1987
Inheritance of Internal Fruit Color in an Interspecific
R. W. Robinson and J. W. Shail
Horticultural Sciences Department, New York State Agricultural Experiment
Station, Geneva, New York
Cucurbita ecuadorensis, which has white flesh color, was
crossed with C. maxima cv. Buttercup, which has deep orange
flesh due primarily to [beta]- carotene. Fruit of the interspecific hybrid had
Acetone extracts of samples from fruit of the parents, F1,
and F2 generations of this cross were scanned with a Beckman
DB spectrophotometer at 440µ, the wave length absorbing [beta] -carotene.
'Buttercup' was high in carotenoids, with readings of 0.98 and above, whereas
C. ecuadorensis showed absorbance readings of 0.03 or less.
The F1 was intermediate, ranging from 0.22 to 0.30. Low concentration
of [beta] -carotene appears to be incompletely dominant.
Transgressive segregation occurred in the F2 . Two of 69 F2
plants had readings of 1.50, higher than any parental plant. Continuous
variation for flesh color occurred in the F2 not only within
the ranges of the parents and F1, but also in the intervening
ranges and beyond. Approximately three-fourths of the F2 population
(49 of 69 plants) had color intensity similar to the F1 or less,
and very few plants had as much [beta] -carotene as 'Buttercup'. Thus, large
populations in segregating generations will be required to combine the high
level of [beta] -carotene of C. maxima with the multiple virus
resistance of C. ecuadorensis.