Breeding of Fruit and Plantation Crops

Induction of seedlessness in fruits

• The seedlessness can be induced by the following methods.

Use of growth regulators

• Application of GA at 8000 ppm in lanolin paste on the cut end of the style of the emasculated flowers of guava resulted in the development of seedless fruits. Similarly, seedlessness in loquat was induced by spraying GA 100 to 200 ppm on the emasculated flowers.

Changing the ploidy level

• It was first demonstrated in Japan that by developing a triploid water melon 2n= 33 by crossing tetraploids x diploid varieties, seedlessness could be achieved. Naturally available seedless guava varieties are due to auto polyploidy (triploid) and not due to parthenocarpic fruit development.

Parthenogenesis

• In some plants, fruits develop parthenocarpically, still they produce viable seeds. (e.g. Mangosteen and Strawberry). This phenomenon is referred to as parthenogenesis. The seedlings of such fruits are genetically uniform. In certain cases, seeds develop partenogentically but they are non-viable (e.g. Apple) When female flowers of jack are pollinated with the pollen grains of bread fruit, seeds do form in jack but they did not germinate as they are non-viable.