Abstract:
Inheritance of the volatile components in bush snap beans,
O.S.U. 58-110 X 'Romano' cross and reciprocal, was determined
using gas-liquid chromatographic technique with gas-entrainment
on-column trapping. A sample of 10 to 14 pods averaging 5 grams
from a single plant was found to be adequate for F₁, F₂, and backcross
studies.
The characteristic low concentration of l-octen-3-ol in O.S.U.
58-110 was dominant over that of the higher concentration of 'Romano'
in the F₁ generation. A chi square goodness of fit test for a 3:1 ratio
in the F₂ and 1:1 ratio in the backcross of the F₁ to 'Romano' indicated
a single dominant gene controlling the inheritance of 1-octen-
3-ol. A better fit to a 9:7 ratio was shown for the F₂, but backcrosses
to both parents did not indicate a two gene action. Backcross
results have shown the importance of studying inheritance by
more than one method.
The difference in mean concentration and the amount of overlapping
in the concentration of linalool found in the two varieties
made it impossible to distinguish any genetic ratios.
Flower color inheritance for crosses involving 'Blue Lake'
types (white flower) X 'Romano' (light purple) were shown to be
controlled by two genes. Dominant gene V subscript [lae] produced the purple
color while the recessive remained white. The second gene, Aeq.
(with other dominant influencing genes) when dominant caused the
banners to be a darker purple color than if the gene was recessive.
No linkage was found between flower color intensifier and 1-octen-
3-ol. It was not possible to determine linkage of the flower color,
V subscript [lae], and l-octen-3-ol.
An oval 'Blue Lake' mutant was found in the line O.S.U. 9025.
Compared to the original round pod type, it was characterized by
strings on both sutures, oval pod, glossy smooth light green outer
skin, and light color inner flesh.
Thawing time, maturity, and processing affected the concentration
of l-octen-3-ol. Concentration of l-octen-3-ol decreased
with maturity (days from anthesis). The concentration in frozen
beans was found to increase with longer thawing times. Processed
samples, whether frozen or canned, were lower in concentration
than fresh raw samples.
Processing influences on other volatiles were mostly quantitative,
but several of the compounds were lost in the frozen samples.
Increases in the "lower boiling" volatiles of the canned products were
attributed to the heat induction and degradation of metabolites. A
loss of volatiles in the frozen samples and "higher boiling" components
in the canned product is believed to be through vaporization and
leaching into the hot water bath during the blanching process. Reduction
in quantity and losses of compounds with influence of thawing
time made the freezing process less desirable for preserving
samples for genetic studies. Fresh raw samples would be better
for inheritance studies if the time required for analysis could be
reduced.
Maturity and the nature of quantitative variation among varieties
would limit the use of volatile flavor components for chemotaxonomy;
yet analysis for phenolics, alkaloids, and flavonoids, combined with
botanical means, should provide the most effective system for differentiating
varieties.
