Nothing
offers more relief than the
bite of a cold juicy cut of watermelon on a hot
summer’s day. Yet, James Kennedy, a chemist
from Australia, claims that what appears to be
both natural and fresh in a watermelon, could not
be farther from the truth. The watermelon that
we have all come to know and love, has been
changed so significantly over the years, that it has
now arguably become a different fruit entirely [1].
Such alterations are not unique to watermelons; in
fact, most modern fruits have been manipulated
and domesticated to suit our tastes.
Farmers have selectively bred desirable
fruit traits for many centuries. Fruits are
essentially the protective vehicle for
seed development and dispersal.
However, unpredictable changes
in weather can significantly var y
the amount of har vest [2]. Thus,
selectivity helps to maintain harvest,
in addition to the obvious result of
breeding the sweetest and largest
fruits. Farmers may also want to control
the production of the fruit breed without
introducing genetic variation, so as to
ensure consistent quality in their products.
Selectivity is achieved through parthenocarpy,
which refers to the production of fruit without
fertilisation of ovules, leading to seedless fruits.
Killing two birds with one stone, it is also a desirable
alternative method for producing fruits that
naturally contain hard seeds, such as grapes,
oranges and bananas, for easier consumption.
Occasionally, parthenocarpy
occurs from natural mutation.
When this serendipitous act
of nature occurs, farmers can
propagate the mutated
p l a n t b y c u t t i n g o r
grafting. After cutting
a section of the plant,
the ends are dipped
i n root hormone and
grown into a new plant.
Alternatively, grafting
involves cutting a part
of the plant and growing
i t on top of the l i v i ng
roots of another plant [3].
Parthenocarpy can also be
artificially induced using incompatible pollen for
fertilisation, such as the crossing of a diploid with
a tetraploid parent. The resulting offspring has
an imbalanced chromosome number, making it
sterile and unable to produce seeds [4].
The major disadvantage to breeding seedless
fruits is the reduction in the diversity of cultivated
fruits, leading to a higher susceptibility to pests
or diseases, which could wipe out all of these
genet ical l y ident ical clones. Such was the
case in 1965, when the fungal Panama disease
infected most of the world’s commercial banana
plantations that grew a common banana species.
The banana i ndus t r y rapidl y scramb l ed to
replace the infected species with an alternative,
Cavendish cultivar, which was immune to the
disease. However, in 1990, a new strain of disease
emerged in Asia and had spread to the African
continent, threatening local African banana
varieties, including the Cavendish banana [5]. The
Food and Agriculture Organisation of the United
Nations (FAO) is urging a global effort in raising
awareness of the disease among banana farmers
and implementing preventative measures to keep
its spread in check.
It has been argued that fruit seeds possess
the highest nutritious value, and consumers are
losing out on nutrients. For instance, sprouted
watermelon seeds are packed with protein,
vitamin B, magnesium and healthy fats [1]. In any
case, it is fair to say that while science makes
our lives more convenient, tinkering with Mother
Nature often has its consequences, whether it is in
the form of diseases or fewer nutrients. Science just
has to evolve alongside it.
